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4.2              AQUEOUS SAMPLING PROCEDURES

4.2.1            General

      There are several requirements that are common to all types of surface water sampling events and are independent of technique.  Several of these requirements are concerned with sample parameters that are inherently difficult to sample.  In addition to the below procedures, overall care must be taken in regards to equipment handling, container handling/storage, decontamination, and record keeping.

      4.2.1.1      Sample collection equipment and non-preserved sample containers must be rinsed with sample water before the actual sample is taken.  Exceptions to this are: oil & grease, TRPH, microbiological, VOCs, or any pre-preserved container.

      4.2.1.2      If protective gloves are used (see Section 4.0.2), they shall be clean, new and disposable.  These should be changed prior to moving to the next sampling point.

      4.2.1.3      Sample containers for source (i.e. concentrated wastes) samples or samples suspected of containing high concentrations of contaminants shall be placed in separate plastic bags immediately after collecting, preserving, tagging, etc.

      4.2.1.4      If possible, ambient, or background samples should be collected by different field teams.  If separate collection is not possible, the ambient or background samples shall be collected first and placed in separate ice chests or shipping containers.  Highly contaminated samples shall never be placed in the same ice chest as environmental samples.  It is a good practice to enclose highly contaminated samples in a plastic bag before placing them in ice chests.  Ice chests or shipping containers with samples suspected of being highly contaminated shall be lined with new, clean, plastic bags.

      4.2.1.5      If possible, one member of the field team should take all the notes, fill out tags, etc., while the other member does all of the sampling.

      4.2.1.6      Teflon or glass is preferred for collecting samples where trace contaminants are of concern.  Equipment constructed of rubber or plastic (e.g., PVC, Tygon, most Van Dorn Samplers) shall not be used to collect samples for trace organic compound analyses.

4.2.2     Special Parameter - Specific Handling Procedures

      1.   Since the concentration standards and/or guidance criteria for many analytes are in the (sub)parts per billion range, extreme care must be taken to prevent cross-contamination.

      2.   Most of the parameter groups listed in sections 4.2.2.1 through 4.2.2.8 below, shall be taken as grab samples unless Department requirements dictate otherwise.  The exceptions are extractable organics and total metals which may be taken as composites, if required.

      3.   There is a greater chance of cross contamination when collecting composites because of increased sample handling and more equipment.

      4.   The following eight categories of parameters have specific sampling techniques and considerations which must be followed to collect unbiased, uncontaminated samples.

      THE PROCEDURES OUTLINED BELOW SHALL BE USED FOR ALL AQUEOUS

SAMPLING (I.E. SURFACE WATER, WASTEWATER, GROUNDWATER, STORMWATER ETC.).

      4.2.2.1      Metals Sampling

a.            Sample containers

      1.      New or properly cleaned plastic containers may be used for metals sampling.  Glass bottles may also be used, but they are prone to breakage and occasionally react with the sample to either leach or adsorb metals from the glass itself.

      2.      All containers for metals sampling, new or previously used, shall be cleaned by following protocols outlined in Section 4.4.1.

      3.      Visually inspect polyethylene or glass containers for defects or contamination.  Discard if defects are present or containers do not appear clean.

b.            Preservation

      1.      Samples shall be preserved with nitric acid (HNO3) of a grade that is suitable for use in trace metals analysis.

      2.      Preservation shall occur within 15 minutes of sample collection or filtration (if applicable) unless collected as a 24-hour composite (see 4.2.4.6.b.5).

      3.      Adequate HNO3 shall be added per liter of sample to reduce the pH to below 2.0 to keep metals in solution and prevent them from adsorbing or absorbing to the container wall.

      4.      If only dissolved metals are to be measured, the sample shall be filtered immediately after sample collection through a 0.45 um membrane filter.  The sample shall not be preserved before filtration.  See Table 4.1 for approved filtration equipment.

      5.      Samples submitted for Chromium VI should not be acidified.

c.            Sample collection protocol:

      1.      Remove the cap from the sample container and rinse container with sample water (if not pre-preserved).  Carefully pour sample into the container without allowing the sampling device to touch the rim of the sample container.

      2.      If adding preservatives in the field, the sample container should not be filled to capacity.

      3.      Acidify the sample to pH of 2 or less by adding a measured quantity of concentrated HNO3 or 1+1 HNO3 into the container.

      4.      NOTE: If containers are pre-preserved by a subcontract laboratory, the sample must be poured into the container slowly to prevent the acid from splattering.  As a precautionary note, the addition of water to acid can generate enough heat to burn unprotected hands.

      5.      Tightly cap the sample container and shake to distribute the acid.  Pour an aliquot of the acidified sample into a disposable container (e.g. sampling cup) or onto a piece of NARROW range pH paper to determine if the pH is less than 2.0.  DO NOT PUT THE pH PAPER DIRECTLY INTO THE SAMPLE CONTAINER!

a.            Field experience has shown that UNDER NORMAL CIRCUMSTANCES, 2 ml of concentrated HNO3 added to 250 ml of sample water will reduce the pH to less than 2.

b.            If the pH is greater than 2, add additional  MEASURED amounts of acid until the pH has been reduced.

c.            Record the total amount of acid that was added to the sample.  This documentation is necessary for the next site visit, since additional acid may need to be added to the sample on subsequent visits.

d.            Acidify at least one of the equipment blank(s) with the GREATEST amount of acid that was required in the sample set and note the amount in field documentation.

      6.      Following proper sample preservation, tightly cap, affix a sample label, apply a seal (if required), and complete the COC or laboratory transmittal form. 

      7.      Aqueous samples for metals need not be cooled to 4 C.

      8.      Make a note on the transmittal form identifying samples that have entrained sediment.

d.            Filtration

      1.      For certain studies or projects, it may be necessary to obtain dissolved (i.e. filtered) samples.  All samples that are filtered shall be identified in field notes and on final reports as "dissolved" or "filtered" metals.

      2.      Specific protocols for collecting dissolved metals from groundwater samples are discussed in Section 4.2.5.6.g.  Filtered samples SHALL NOT be collected from groundwater sources unless:

a.            The Department has required or approved the protocol; or

b.            The organization feels that the contamination is directly related to the suspended material rather than the groundwater.  In this case, BOTH unfiltered and filtered samples shall be collected and analyzed.  The results shall be submitted to the Department for review.  Based on the data, the Department may require continued collection of unfiltered samples, BOTH unfiltered and filtered samples or only filtered samples.

      3.      Surface water samples may use the sample protocols that are specified for groundwater (Section 4.2.5.6.g.)  These protocols are recommended when sampling static surface water sources (i.e. subsurface samples from lakes, ponds, lagoons or ocean) since exposure to air can change the concentration of metals in solution.  When sampling from moving sources (i.e. rivers or streams) or just below the surface, filtered samples may be collected into an intermediate container and filtered with syringe-type or tripod type filtration units.

      4.      Allowing a sample to settle and decanting the supernate (upper water layer) has been proposed as a means of removing suspended material.  This technique MAY NOT be used for groundwater samples, and is not recommended for other sources because:

a.            Settling times techniques are highly dependent on particle size and concentration and may not be reproducible;

b.            Preservation for metals must occur within 15 minutes of sample collection which may not be sufficiently long for highly turbid samples to settle; and

c.            The analytical results cannot be reported as "total" or "dissolved".

            If this technique is used, the following protocols must be followed:

a.            Samples shall not be acidified before settling occurs;

b.            Total time for settling shall not exceed 15 minutes;

c.            The resultant supernate shall be carefully decanted into an appropriate container and preserved using protocols described above;

d.            Field notes shall specify the length of time the sample was allowed to settle, as well as observations on the initial and final (supernate); and

e.            The final report shall identify the technique that was used to collect the sample (i.e. decanted).

f.            NOTE:  samples SHALL NOT be transported back to the laboratory for settling, UNLESS entire procedure (transport, settling, decanting and preservation) can occur within 15 minutes of sample collection.

      4.2.2.2      Extractable Organics and Pesticides

            Conventional sampling practices shall incorporate the following special considerations.  Oil & Grease (O&G) and Total Recoverable Petroleum Hydrocarbons (TRPH) shall follow protocols outlined in Section 4.2.2.5 below. 

a.            Sample containers

      1.      Collect all samples in glass containers (1 liter to 1 gal.) with Teflon-lined caps.  Note:  Teflon containers are also acceptable.

      2.      Amber glass should be used for PAHs, nitrosamines, nitroaromatics, and isophorone.

      3.      Visually inspect glass bottles to assure that there are no glass or liner defects.  If defects are present and/or the sample containers do not appear clean, the bottles must be discarded.

      4.      Sample containers must be cleaned according to the protocols specified in Section 4.4.1.

      5.      Composite samples from automatic WW samplers must be collected in refrigerated glass containers through Teflon tubing.

b.            Preservation

      1.      Tables 4.2 and 4.3 must be followed to determine the specific preservation method for each group of organic compounds and pesticides.

      2.      All samples must be placed on wet ice immediately after collection.  Samples must be maintained at a temperature of 4 C.

      3.      If the samples for pesticides cannot be extracted within 72 hours of collection, the sample pH must be in the range of pH 5 to 9.  If needed, sample must be adjusted to the specified pH range with sodium hydroxide or sulfuric acid.

      4.      Other extractable samples need not be pH-adjusted with acid or base.

      5.      Samples must be extracted within 7 days of sample collection and the extracts analyzed within 40 days of extraction.

      6.      If residual chlorine is present, sodium thiosulfate must be added.

c.            Sample collection protocol:

      1.      Sample bottles should be prerinsed with sample before collection, except Total Recoverable Petroleum Hydrocarbons (TRPH), Oil & Grease, etc. (see 4.0.3) or any prepreserved sample container.

      2.      Remove the cap from the bottle without touching the Teflon liner.

      3.      Do not allow the sampling equipment or hands to touch the rim of the sample container.

a.            For bailer sampling, it may be necessary to utilize a stainless steel or Teflon delivery tube (fits into the bottom of the bailer).

      4.      Fill bottle with sample to almost full capacity.

      5.      Quickly place the Teflon lined cap over the bottle and tighten securely.

      6.      Affix a sample label, seal (if required), and complete the chain-of-custody form. 

      7.      Put the sample bottle in a plastic sample bag and place on wet ice immediately.

      8.      Make a note on the lab transmittal form identifying samples that appear highly contaminated or exhibit other abnormal characteristics (i.e. foaming, odor, etc.).

      4.2.2.3      Volatiles Sampling

a.            Sample containers

      1.      Analysis of volatile organic substances requires a glass sample vial, sealed with a teflon-coated septum.

      2.      AT A MINIMUM, duplicate samples must be collected, although some laboratories require three or more vials.  If the containers are not supplied by the laboratory, verify the laboratory's policy on how many vials are necessary and collect the specified number of vials.

      3.      Visually inspect the glass vials to assure that there are no glass or septum defects (e.g. rim must have not nicks or visible depressions); septum must not be deformed, etc.).  If defects are present and/or sample containers or septums do not appear to be clean, the vials must be discarded.

      4.      Sample vials may be purchased precleaned from commercial vendors, or must be cleaned according to protocols outlined in Section 4.4.1.

      5.      NOTE:  VIALS FOR VOCS ARE NOT RINSED WITH SAMPLE.

b.            Preservation

      1.      Table 4.2 must be followed to determine the specific preservation method for each group of volatile organic compounds.

      2.      If residual chlorine is not present, the vials shall be filled with the sample, acidified (prepreserved containers are acceptable) with HCl and labeled "preserved".

      3.      If the volatile aromatics are to be analyzed within 7 days, HCl is not necessary.

      4.      Sodium thiosulfate must be added to samples with residual chlorine (see sampling protocols below).

      5.      Samples must be placed on wet ice immediately after sample collection.  A temperature of 4 C must be maintained until the sample has arrived at the laboratory.

c.            Sample collection protocols:

      1.      All fuel or exhaust sources which could cause VOC contamination must be situated well away and downwind of the sampling site (see Section 4.0.5).

a.            If possible, fuels should be transported and stored in a separate vehicle from empty vials and collected samples.

b.            All petroleum fueled engines (including the vehicle) must be situated downwind of the sampling operations.

            2.            Samples shall not be aerated during sample collection.

a.            Extreme caution must be exercised when filling a vial to avoid any turbulence which could promote volatilization. 

b.            Carefully pour the sample down the SIDE of the vial to minimize turbulence.  As a rule, it is best to gently pour the last few drops into the vial so that surface tension holds the water in a "convex meniscus."

      3.      Do not allow the sampling equipment to touch the rim of the sample container.

a.            For bailer sampling, it may be necessary utilize a stainless steel or Teflon delivery tube or “pigtail"  to obtain a gentle trickle of sample into the vial.

b.            It is sometimes difficult to completely fill the vial directly from some waste streams.  The sample may be collected in a precleaned intermediate sample collection device made of the appropriate materials (see Table 4.1) and carefully poured into the VOC vials.

      4.      The investigator must determine if the water to be sampled contains residual chlorine.

a.            If residual chlorine is present; add 10 mg of sodium thiosulfate to the vial (laboratory may supply vials with premeasured quantities).

b.            Fill the vial 90% with sample.

c.            Add four drops of concentrated HCl (more acid may be needed if the sample is known to contain high levels of bicarbonate or is otherwise buffered).  Add additional sample (if needed) to create a convex meniscus and cap with zero headspace (see 5 below).

d.            Label vial appropriately (preserved/sodium thiosulfate/acid).

      5.      The sample must be collected so that there are no air bubbles in the container after the screw cap and septum seal are applied.

a.            Vial must be filled so that the sample surface is above the container rim (convex meniscus).

b.            The cap with the septum is then quickly applied (make sure teflon side of septum is down).  Some sample may overflow, but air space in the bottle must be eliminated. 

c.            If acid has been added to the sample, tip the vial gently two or three times to distribute the preservative.

d.            Turn the bottle over and tap it to check for bubbles.

            1.            If any are present, remove the cap, add a few more drops of sample, recap and test for bubbles.  REPEAT NO MORE THAN 3 TIMES.

      6.      Sampling and preservation containers may be prelabeled prior to any field activities. This may reduce confusion during a sampling event.

      7.      All the vials must be labeled.  Make note in the field records of any samples that appear highly contaminated or appear to effervesce when acid is added.  NOTE:  If the sample reacts with the acid by generating gas, DER recommends collecting unpreserved samples for analysis (seven-day holding time must be met).

      8.      Wrap each vial in bubble-wrap, or equivalent, and place each vial in a small ziplock-type bag and immediately place on wet ice.

      9.      Complete field records.

      10.      Protect samples from environmental contamination during storage and transport to the laboratory (4.2.2.3.c.1 above).

a.            As an added measure, replicate samples may be sealed in a container with vermiculite.  This will add further protection from potential contamination.

      4.2.2.4      Bacteriological Sampling

a.            Sample containers

      1.      Samples must be collected in containers that have been sterilized according to Standard Methods (17th Edition) or the EPA's Microbiological Methods for Monitoring the Environment, 14th edition.

a.            Presterilized Whirlpak bags (or equivalent) are typically used for sampling.

b.            If Whirlpaks are not used, a 125 ml or larger sample container must be used to provide a minimum sample volume of 100 ml and adequate mixing space.

      2.      Unlined caps or ground glass tops shall be used to ensure complete sterilization of the container's closure. 

      3.      Bottles and caps shall be sterilized according to protocols outlined in Section 4.4.1 or purchased presterilized from a commercial vendor.

b.            Preservation

      1.      Samples shall be preserved according to Tables 4.2 and 4.5.

      2.      All samples shall be place on wet ice immediately after sample collection.

      3.      When sampling water containing residual chlorine, a dechlorinating agent such as sodium thiosulfate must be added to the sample container. 

a.            The final concentration of sodium thiosulfate in the sample shall be approximately 100 milligram per liter (mg/L) in the sample.

b.            As a general rule, this concentration may be achieved by adding 0.1 ml of a 10 percent solution of sodium thiosulfate to a 125 ml sample bottle.

c.            The dechlorinating agent neutralizes any residual chlorine and will prevent further reaction between bacteria and chlorine.

      4.      ANALYSIS MUST COMMENCE WITHIN 6 HOURS FOR NON-POTABLE SOURCES AND 30 HOURS FOR POTABLE SOURCES.  Special laboratory arrangements may need to be made so that the holding times are not compromised (may require local lab analysis).

c.            Sample Collection Protocols:

      1.      Bacteriological sampling must always be collected as a grab sample and must never be composited. 

      2.      The container must be kept unopened until the moment that the sample is collected.

      3.      DO NOT RINSE CONTAINER BEFORE COLLECTING SAMPLE.

      4.      When the Whirlpak bag or sample bottle must be lowered into the waste stream, either because of safety or impracticality (manhole, slippery effluent area, etc.), care must be taken to avoid contamination.

      5.      Samples shall never be collected in an unsterilized sample container and transferred to a sterile container.

      6.      Be careful not to put fingers into the mouth of the container or on the interior of the cap.

      7.      If sampling intermediate sampling devices (i.e. bailers) or from in-place plumbing, the sampling device or the tap do not need to be disinfected (i.e. swabbing with alcohol or flaming with heat source).

a.            Intermediate sampling devices shall be thoroughly rinsed with sample water prior to collecting the sample.  For this reason, microbiological samples should be among the final samples that are collected from the sampling location.

b.            Spigots shall be flushed at maximum velocity (see Sections 4.2.6 and 4.2.7) to purge the system and remove particulates.  Sample flow shall be reduced to approximately 500 ml/min and allowed to run a few minutes before collecting samples (or microbiological samples may be collected last).  DO NOT STOP FLOW BEFORE OR DURING THE FILLING PROCESS.

            8.            Surface water sample collection:

a.            To sample with a rigid container, hold the bottle near the base and plunge neck downward, below the surface.  Turn container until the neck points slightly upward with the mouth directed toward the current.  Fill to within about 1/2 inch of the top and recap immediately.

b.            To sample with a Whirlpak bag, open the bag by zipping off the top and pulling the white tabs to open the bag.  Hold the bag in the hand or attach to a long handle and plunge neck downward and up in one sweeping arc.

            9.            Intermediate containers (i.e. bailers)

a.            Obtain sufficient sample in the sample collection device to completely fill the sample container.

b.            Begin pouring sample out of the device BEFORE collecting into the container.

c.            Continue to pour sample out of the device, place container under flowing stream, and fill.  DO NOT STOP FLOW BEFORE OR DURING THE FILLING PROCESS.

            10.            Wells with in-place plumbing, spigots and/or faucets

a.            Samples shall be collected after flow has been reduced to 500/ml per minute.

b.            Allow the water to flow at the reduced rate for a few minutes before collecting the sample, or collect all other samples prior to taking the microbiological sample.

c.            DO NOT STOP FLOW BEFORE OR DURING THE FILLING PROCESS.

      4.2.2.5      Oil and Grease (O&G) and Total Recoverable Petroleum

Hydrocarbon (TRPH) Sampling

a.            Sample Containers

      1.      Samples for O&G and TRPH shall be collected in 1 liter wide-mouth glass bottles.

a.            The lid shall be teflon-lined.

b.            If the cap is not teflon-lined, a sheet of teflon extending out from the lid may be used.

      2.      Visually inspect glass bottles to assure there are no glass or cap defects.  If defects are present and/or sample containers do not appear to be clean, the bottles should be discarded.

b.            Sample Preservation

      1.      Since losses of the product will occur on sampling equipment, composite samples shall not be collected.

      2.      The sample must be immediately preserved by adding H2SO4 or HCl to reduce the pH to 2.0 or less.

      3.      Samples must be placed on wet ice immediately after preservation.  The temperature of the sample must be maintained at 4 C until received and processed by the laboratory.

c.            Selection of Sampling points

      1.      Oil and grease may be present in wastewater as a surface film, an emulsion, a solution, or as a combination of these forms.  Since it is very difficult to collect a representative ambient sample for oil and grease analysis, the sampler must carefully evaluate the location of the sampling point.

      2.      The most desirable sampling location for both O&G and TRPH is the point where greatest mixing is occurring.  Quiescent areas should be avoided, if possible.

      3.      Skimming the surface for the sample is unacceptable.

      4.      For compliance samples at a facility you may want to take samples at the worst place.

      5.      Neither the container, nor the sampling device, shall be rinsed before the actual sample is taken.

      6.      COMPOSITE SAMPLES SHALL NOT BE COLLECTED.  If composite data is required, individual grab samples that are collected at prescribed time intervals must be analyzed separately to obtain the average concentrations over an extended period.

d.            Sampling Protocols

      1.      Sampling for these products is unique because they are immiscible and tend to adhere to the sampling device; therefore, these sample shall always be a grab sample.

      2.      The sample, when collected, should not be transferred to another container.  The analytical methods require the use of the entire sample.  In addition, the sample container must be rinsed with solvent as a part of the laboratory analytical process.  Therefore these samples must be separate and discrete samples that will be used only for the O&G or TRPH analysis.

      3.      Remove the cap from the glass bottle without contacting the interior of the container or lid. 

      4.      DO NOT RINSE THE BOTTLE WITH SAMPLE WATER.

      5.      Whenever possible samples should be collected directly into an unpreserved sample container.  If intermediate sampling equipment is used, do not allow the sampling equipment to touch the rim of the sample container.  AUTOMATIC SAMPLERS SHALL NOT BE USED TO COLLECT THESE TYPES OF SAMPLES.

      6.      Fill the bottle with the sample water to almost full capacity.

      7.      Add preservatives and check the pH using the protocols outlined in 4.4.2.2.b.

      8.      Quickly cap the container and tighten securely.

      9.      Affix a sample label, seal (if required), and complete the chain-of-custody form.

      10.  Protect glass container from breakage ("bubble wrap" is recommended), place the sample bottle in a plastic sample bag and keep it cool to 4 C on wet ice.

      11.  Make a note on the lab transmittal form identifying samples that may be highly contaminated or any other unusual observations.

      4.2.2.6      Radiological Sampling (Excludes Radon)

a.            Sample containers

      1.      Polyethylene, polyvinyl chloride (PVC), or Teflon containers are recommended for collecting radioactive samples because these containers are less adsorbent than glass or metal containers.  Since radioactive elements are often present in extremely low quantities, a large fraction of the elements may be lost by adsorption on containers or glassware surfaces used in analyses.  This loss may, in turn, cause a loss of radioactivity and possibly contaminate subsequent samples due to reuse of inadequately cleaned containers.  Glass bottles are also more susceptible to breakage during handling than plastic containers.

      2.      Containers shall be cleaned according to the protocols specified in Section 4.4.1.

b.            Preservation

      1.      The preservation technique for radiological sampling is acidification to a pH of less than 2.0 with concentrated or 1+1 nitric acid (HNO3). 

      2.      The pH shall be checked in the field following the protocols described 4.4.2.2.b.

c.            Sampling Protocols

            Prior to sampling, the area may be surveyed with a beta-gamma survey instrument, such as a Geiger-Maller meter.  If radiation levels are above instrument background, the investigator should consult a radiation safety specialist to determine appropriate safety procedures.

      4.2.2.7      Radon Sampling

      Radon is a gas and is easily removed from water sources.  Therefore, the same precautions and care used to collect volatile organic samples shall be followed.  It is extremely important to minimize contact with air during sample collection.

a.            Sample Containers

      1.      Glass sample vials shall be obtained from the analyzing laboratory and shall contain a premeasured portion of the scintillation "cocktail".

      2.      A minimum of two samples is required.  Laboratories are expected to provide the sampler with the requisite number of containers for each sample.

b.            Preservation - the scintillation cocktail is the only required preservative.

c.            Sampling Protocol

            The laboratory should provide specific sample collection instructions that must be followed.  These protocols should included proper handling as well a sample size and packing instructions.  The following are general instructions that should be used:

      1.      Carefully fill a syringe (usually 10 ml) with sample water so that air bubbles are not pulled in with the sample before, during or after filling.

      2.      Place the tip of the syringe BELOW the scintillation cocktail and slowly dispense the sample BENEATH the cocktail surface.

      3.      Replace lid and cap tightly.

      4.      Generally the vial is used in the laboratory analytical instrument and labels or ID numbers on the sides of the containers may interfere with the analysis.  Check with the laboratory for proper placement of labels or field ID numbers.

      5.      Ship in an upright position in the shipping containers that have been provided by the laboratory.  If none are provided, protect vials from breakage (bubble wrap is recommended), segregate replicate samples in separate plastic bags, and ship to laboratory in an upright position.

      4.2.2.8      Cyanide Sampling

      Cyanide is a very reactive and unstable compound.  Cyanide should be analyzed as soon as possible after collection.  Note that the currently approved method (Standard Methods and EPA MCAWW) is being rewritten due to some inaccuracies in the method language.

a.            Sample Containers

      1.      The sample container shall be polyethylene or glass. 

      2.      Containers shall be cleaned in accordance with protocols outlined in Section 4.4.1 of this manual.

b.            Preservation

      Sulfides tend to be a regional problem in Florida and can cause interference with cyanide analyses.

      1.      Proper preservation of aqueous cyanide samples must follow the standard procedures listed below.

      2.      All samples shall be tested for sulfides with test papers (EM, Chemometrics) or kits (HACH). However, these tests may not detect sulfides in low enough concentrations to be useful.

      3.      Ultimately, all samples shall be preserved to a pH of greater than 12 with sodium hydroxide and placed on wet ice immediately after preservation.  A temperature of 4 C shall be maintained until analysis begins at the laboratory.  The pH of the samples shall be checked to assure proper pH (see 4.4.2.2.b).

      4.      Samples that may or may not contain sulfides must be preserved in one of two ways: (1) samples are tested for sulfides, preserved with NaOH to a pH>12 and sent to the lab for analysis within 24 hours; or (2) tested for sulfides and pretreated as follows:

a.            Test for sulfides

      1)      Samples with visible particulates must be filtered. Keep this filter (#1);

      2)      Sulfides may be tested with test papers (EM, Chemometrics) or kits (HACH). Tests may not detect sulfides in low enough concentrations to be useful;

      3)      Remove sulfide by adding cadmium (or lead) nitrate (or carbonate) powder to the sample (filtrate) to precipitate the sulfides;

      4)      Test for presence of sulfides. Repeat steps 2 and 3 until the test shows no sulfides are present;

      5)      Remove the precipitate (sulfides) from the sample by filtration and discard this filter.

b.            Preservation

      1)      Reconstitute the sample by adding the solids collected on filter #1 back into the filtrate;

      2)      Add NaOH until the sample pH > 12 and cool to 4 C;

      3)      Maximum holding time is now 14 days;

      4)      Equipment blanks must be handled the same as real samples.

      5.      All samples known to contain oxidizing agents (chlorine) must first be tested as follows:

a.            Test sample with KI-starch paper;

b.            Add a few crystals of ascorbic acid, mix sample and retest.

c.            Continue to add ascorbic acid until the test is negative;

d.            Add an additional 0.6 grams of ascorbic acid per liter of sample to remove chlorine.

4.2.3            Surface Water Sampling

      4.2.3.1      Introduction and Scope

      [[Surface water samples may be taken for several reasons.  Ambient conditions can be documented for a single point in time to determine if threshold Water Quality parameter limits are being met.  Long-term sampling of a site or watershed may be used to document trend analysis.  All of these items can be used to determine if a particular surface water body (or segment) is meeting its designated use.  Sediment sampling may provide confirmatory information as to contaminants that are presently

contained in the water column as well as an historical account of those contaminants that settled or precipitated out of the water column.  Physical conditions of the water body and physico-chemical properties of the contaminants will determine their movement in and out of the water column.  Additional information on data use, study objectives, etc. can be found in the EPA Region IV SOP & QAM, February 1991, Section 4.8.1.   This document will henceforth be referred to as the EPA SOP.

      Sample site selection is dependent upon the three major groupings; lakes, estuaries, and streams.  Sites may have already been predetermined by a EPA, DER, WMD, etc. permit or by designation as a permanent monitoring station (PMS).  If these sites have not already been designated as above or by the DER water or waste program for which this sampling event has been required, then refer to the general descriptions in the EPA SOP, Sections 4.8.2.  The EPA document provides generalized descriptions for proper site choices.  Only sampling procedures will be described in the following sections.]]

      This section presents the standard operating procedures that shall be employed during field investigations to ensure that representative surface water samples are collected.  The particular surface water types that will be addressed include; static lakes, ponds, and impoundments; tidally-influenced estuarine areas; as well as streams and rivers.  The importance of proper sampling of this varied matrix cannot be overemphasized.  Proper sampling for the submerged (or emergent) sediments that underlie these surface water bodies is equally important.  Care should be taken so that samples are neither altered nor contaminated by sample handling procedures.

      This section discusses grab, depth-specific, and depth composited surface water samples.  Information regarding flow- or time-weighted aqueous sampling is found in the Wastewater Sampling section.

      4.2.3.2      General

      Access will be left up to the sampling group.  Ease of access should not be the main criteria for sampling site choice.  If sampling from a bridge, by boat, or by wading, there are certain precautions that must be considered: 

a.            If sampling with a boat, samples should be taken from the bow, away and upwind from any gasoline outboard engine (see 4.0.5.1).

b.            Collect samples upstream from the body when wading in to collect water samples.

c.            Care should be taken not to disturb sediments when taking samples in lakes, ponds, impoundments.

d.            If water samples and sediment samples are to be taken from the same area, the water samples must be taken first.

e.            Sampling at or near structures (dams, weirs, bridges) may not provide representative data because of unnatural flow patterns.

f.            Surface water and/or sediments should always be collected from downstream to upstream.

      4.2.3.3      Sample Acquisition

      Three (3) types of general sample acquisition methods will be discussed:  grab samplers; mid-depth samplers; and composite samplers.

a.            Grab Sampling

      1.      If the sample media is homogenous, grab samples are an effective and simple technique.  If homogeneity is not known (and should never be assumed) then other techniques must be used.

      2.      Surface grabs using unpreserved sample containers are encouraged since the sample container is used for collecting the sample and, after appropriate preservation, the same container can be submitted for laboratory analysis.  This reduces sample handling and eliminates potential contamination from other sources (i.e. additional sampling equipment, environment, etc.).  If the laboratory provides prepreserved sample containers, the sample shall be collected in an UNPRESERVED sample container or with sampling equipment.  The container or equipment shall be of appropriate construction (see Table 4.1) and the sample shall be transferred immediately into the prepreserved sample container

      3.      Simple Grab Samples - Typical sample collection equipment includes not only sample containers, but also precleaned beakers, buckets, and dippers.  These samplers must be constructed appropriately (including handles):

a.            Sample Container (unpreserved)

      1.      submerge the container, neck first into the water,

      2.      invert the bottle so the neck is upright and pointing into the water flow (if applicable),

      3.      return the filled container quickly to the surface,

      4.      shake to rinse the interior surface of the container and pour contents out downstream of sample location (see restrictions outlined in 4.0.3)

      5.      Collect sample as described in steps 1,2 and 3 above.

      6.      pour out a few mls of sample downstream of sample collection.  This allows for addition of preservatives and sample expansion

      7.      Securely cap container, and label.

b.            Intermediate vessel

      1.      Collect sample as outlined in 3.a above.

      2.      Pour into prepreserved sample container (or field preserve per Section 4.4.2.2.a), check pH per Section 4.4.2.2.b (if applicable), cap, and label.

            4.            Pond Sampler - Another effective technique is using a pole-mounted flask, beaker, or container.  A long, telescoping pole (swimming pool supply) is outfitted with a (non-contaminating) clamp.  An appropriately constructed and shaped container is fitted into the clamp.  In this way the sample can be taken away from the shore, boat, bridge, etc. and at a specific spot.  The sampling vessel can be constructed of all-inert material so that all parameters can be sampled. 

a.            Submerge the clamped container neck first, invert and withdraw from water.

b.            Be careful not to entrain sediments or skim the water surface.

c.            Rinse container (restrictions specified in Section 4.0.3 must be observed), resubmerge and collect sample.  Retrieve the pole, clamp, and container and fill the sample containers.

      5.      Pump and Tubing - Although the use of a peristaltic pump and tubing can provide an adequate mid-depth or depth composite, it can also be used for taking a grab sample.  This would be especially helpful if a large amount of sample is needed.

a.            Lower appropriately precleaned tubing to a depth just below the water surface (6 - 12 inches).

b.            Turn the pump on.

c.            Allow several tube volumes to pump through the system to acclimate the tubing.

d.            Make sure the tubing does not come out of the water and inadvertently pull some surface skim water through the tubing (this may bias sample results).

e.            Fill the individual sample bottles via the discharge tubing.

            NOTE:  THIS TECHNIQUE IS NOT ACCEPTABLE FOR OIL & GREASE, TRPH OR VOCs.  It is not recommended for extractable organics (requires the organic trap setup, see Fig. 4.1) or microbiologicals (new, unused tubing, including tubing in the sampling head are required at each sampling location).

b.            Mid-Depth Sampling

      1.      Mid-depth samples or samples taken at a specific depth can approximate the conditions throughout the entire water column.

a.            One sample may be taken when the water body is assumed to be homogenous.

b.            Additional samples can be taken from different depths at one spot to get a much more exact approximation of the conditions.

c.            Many times a single site will be sampled from: just below the surface; mid-depth; and just above the bottom (sediment). 

d.            Accurate sampler location is imperative for this sampling technique.

      2.      The equipment that may be used for this type of sampling are:  a device designed specifically for depth-specific sampling (kemmerer, niskin, beta, etc.); pumps with tubing; or double check valve bailers.

a.            Samplers are available from many manufacturers and in a variety of configurations and construction materials.

b.            When purchasing and choosing a device for a particular sampling event, please be aware that certain construction material details may preclude its use for certain parameters (see Table 4.1):

      1.      Many kemmerer samplers are constructed of plastic and rubber which precludes their use for all organic sampling parameters (volatile and semivolatile).

      2.      Some of the newer devices are constructed of stainless steel or are all-Teflon or Teflon coated.  These would be acceptable for all parameter groups without restriction.

      3.      NOTE THAT ALL RELATED COMPONENTS (STOPPERS, ETC.) MUST BE CONSTRUCTED OF INERT MATERIAL AS WELL IF ORGANICS ARE TO BE SAMPLED.

            3.            Kemmerer, niskin, and beta type devices

a.            Separate and specific deployment discussions are not provided in this document.  Manufacturers suggestions shall be followed for specific procedures.

      1.      Before lowering the sampler, measure the water column to determine maximum depth and sampling depth. 

      2.      The line attached to the sampler should be marked with depth increments so that the sampling depth can be accurately recorded.

      3.      When dropping the sampler to the appropriate depth, it should be done slowly so that sediments are not stirred up.

      4.      Once the desired depth is reached, send the messenger weight down to trip the mechanism.

      5.      The sampler should be lowered and retrieved slowly.

      6.      The first sample shall be discarded into a bucket (to be dumped at conclusion of sampling).

            4.            Double check-valve bailers

a.            Sampling with these type of bailers shall follow the same protocols outlined in 3 above.

b.            Although not designed specifically for this kind of sampling, it will be acceptable when a mid-depth sample is required.

c.            Note:  this sampler does not perform as well as the devices described above or the pump and tubing described in the next section.

d.            As the bailer is dropped through the water column, water will be displaced through the body of the bailer.  The degree of displacement is dependent upon the check valve ball getting out of the way and allowing water to flow freely through the bailer body.

e.            An open-top bailer may also be used, but is not recommended.  The open-top arrangement will not prevent water from being exchanged in the top portion of the bailer.

f.            A closed-top bailer does not allow free water displacement on descent at all and is not acceptable.

g.            The bailer should be dropped slowly to the appropriate depth.  Upon retrieval, the (two) check valves seat, preventing water from escaping out of or entering the bailer.

            5.            Pump and Tubing

a.            The most portable pump for this technique is a (12 volt) peristaltic pump.

b.            Appropriately precleaned silastic is required in the pump head and HDPE, Tygon, etc. tubing is attached to the pump.

c.            Measure the water column to determine the maximum depth and the sampling depth.

d.            Tubing will need to be tied to a stiff pole or be weighted down so the tubing placement will be secure. 

      1.      A lead weight should not be used.

      2.      Any dense, non-contaminating, non-interfering material will work (brick, SS weight, etc.).

      3.      Tie the weight with a lanyard (braided or monofilament nylon, etc.) so that it is located below the inlet of the tubing.

e.            Turn the pump on and allow several tubing volumes of water to be discharged before taking the first sample.

f.            Sample containers are then filled in the proper order, preserved, labeled, and placed on ice (if required).

c.            Composite Sampling

            Composite sampling will be used when a single sample that approximates a given depth interval is desired.  Any of the devices described in mid-depth sampling can be used for composite sampling.  The devices must be activated or manipulated in a way that the actual volumes sampled within the interval are ALL EQUAL PROPORTIONS.   For instance, because of head pressure, the pump and tubing will pull a greater volume of sample at 5 feet in comparison to 20 feet.  For this reason, great care must be used so that sample results are not biased.  The use of the niskin, kemmerer, beta, bailers, etc. containers may take more time, but sample control will be greater.

4.2.4            Wastewater Sampling

      4.2.4.1      Introduction and Scope

      Prior to mobilizing, the sampler must decide what kind of samples to collect, for what parameters, and where to collect them.  This section will provide the guidelines as to what kind of sample should be collected, where it should be collected, and how to collect it.  It will also discuss choosing parameters for analysis.  Care must be taken to ensure that the sampling location is correct and that the samples are representative of the discharge.  The site must be consistent with its permit. 

      This section is also applicable to stormwater runoff sampling.

      [[4.2.4.2      Site Selection

      The following discussion deals with site selection, sampling points and sample collection strategies and are for educational and informational use.

a.            Samples shall be collected at the appropriate permitted locations and at locations necessary to determine environmental impact (e.g., effluent outfall, ground water monitoring well, land application site, receiving water stations).

      1.      If the permitted sampling point is not adequate for collecting a representative sample, the sampler should determine the most representative sampling point available and collect samples at both locations.  This should be done with the concurrence of DER and the facility.

      2.      The reason should be documented in the field log for later resolution if challenged and for consideration of correcting the sampling point during permit renewal.

      3.      Recommendations for a change in sampling location should be given to the DER permit writer.  Sample locations should be specified in such detail that anyone could follow the directions to the site and collect a sample at the same place.

b.            The following are the most common locations for collecting a sample at a facility.  They may or may not be described in the permit.

            1.            Effluent - Effluent samples should be collected at the site specified in the permit, or if no site is specified in the permit, at the most representative site downstream from all entering wastewater streams prior to discharge to the appropriate disposal method (e.g., surface water discharge, ground water discharge, wetlands discharge, deep-well injection).

      2.      Influent - Influent wastewaters are preferably sampled at points of highly turbulent flow in order to ensure good mixing;  however, in many instances the most desirable location may not be accessible.  Preferable influent wastewater sampling points include:

a.            the upflow siphon following a comminutor (in absence of grit chamber);

b.            the upflow distribution box following pumping from main plant wet well;

c.            aerated grit chamber;

d.            flume throat;

e.            pump wet well when the pump is operating.

            In all cases, influent samples shall be collected upstream from recirculated plant supernatant and residuals, and the sample collected should be completely untreated.

      3.      Internal Outfalls - Internal outfalls are to be sampled as specified in the permit or consent order.

a.            This type of sampling occurs on special projects, on industries or domestic facilities undergoing a diagnostic inspection, on treatment trains in a facility which are essential to the final effluent quality, and on facilities which occupy watersheds (e.g., phosphate mines).

b.            Sampling of internal outfalls is uncommon, but can be useful in identifying potential equipment problems and unidentified contaminant sources.

      4.      Groundwater Monitoring Wells - Ground water monitoring wells should be sampled as described in the Groundwater Section.

      5.      Groundwater Discharge Sites - Sample collection of discharges to land application sites and underground injection wells are best taken at the effluent sampling points.

      6.      Residuals - Residual samples should be taken in accordance with EPA's POTW Sludge Sampling and Analysis Guidance Document, 1989.

      7.      Residual Sites - Samples taken at a residuals disposal site are taken to determine build-up of pollutants in the soils.

      8.      Pond and Lagoon Sampling - Generally, composite wastewater samples should be collected from ponds and lagoons.  Even if the ponds or lagoons have long retention times, composite sampling is necessary because of the tendency of ponds and lagoons to stratify.  However, if dye studies or facility data indicate a homogeneous discharge, a grab sample may be taken as representative of the waste stream.

      9.      Surface Water Sites - The location of surface water sampling sites for wastewater facilities depend on whether the facility discharges to a unidirectional flowing body of water (e.g., stream, river) or a non-unidirectionally flowing body of water (e.g., tidally influenced coastal rivers, bays, estuaries, lakes). 

a.            Unidirectional Flow Streams - The upstream control site, if one exists, should be just far enough upstream to be out of the influence of any effluent.  This may entail going farther upstream to avoid any potential groundwater contamination from adjacent spray irrigation sites or percolation ponds. 

      1.      The downstream or test site should be at the edge of any mixing zone (if there is one) and far enough downstream to be in the peak zone of impact.  These sites should be determined on a case-by-case basis.

      2.      The control and test sites should be matched as closely as possible on habitat structure (e.g., flora, pool/riffle type, shading) based on a habitat analysis.

      3.      If there is no upstream site (e.g., when the discharger currently forms the upstream flow), then a reference site should be chosen in a nearby stream based on a habitat analysis.

b.            Nonunidirectional Flow Water Bodies - For tidally influenced rivers, bays, estuaries, swamps, lakes, ponds, and other water bodies which don't have unidirectional flow, an unimpacted reference site must be selected.

      1.      The site should be matched carefully on habitat structure (e.g., type, sediments, stream order/size, type of drainage) to ensure you are comparing the same type of sites.

      2.      The outfall should have two test sites either at the edge of the mixing zone or in the predicted zone of impact.  The two sites should be located in different directions depending on where the effluent plume would be expected during tidal changes, in the direction of prevailing wind, or along anticipated flow gradients even though undetectable.

      10.      Effluent limits in a permit are often specified as a mass loading.  To determine a mass loading and thereby evaluate compliance with permit limits, it is necessary for the sampler to obtain accurate flow data.  Flow measurement is the commonly used term for this process.  In addition to verifying compliance with permit limits, flow measurement serves to:

a.            Provide operating and performance data on the wastewater treatment plant

b.            Compute treatment costs, based on wastewater volume

c.            Obtain data for long-term planning of plant capacity.

            Specific operating instructions for automatic samplers, capabilities, capacities, and other pertinent information are included in the respective operating manuals and are not presented here.]]

      4.2.4.3      Sample Types

            There are two primary types of samples:  1) grab samples; and 2) composite samples.  Each type has distinct advantages and disadvantages.  In order to obtain a more complete characterization of a specific facility's effluent, the two sample types can be used independently or in combination.

a.            Grab Samples

      1.      This is an individual sample collected over a period of time, usually all in one motion, generally not exceeding 15 minutes.  The 15 minute time limit applies to aqueous samples only.  No particular time limit applies to the  collection of solid samples (e.g. residuals).  Grab samples may be used to determine consistency between an industry's self-monitoring data and to corroborate the results of composite samples.

      2.      Grab samples represent the conditions that exist at the moment the sample is collected and do not necessarily represent conditions at any other time.  Grab sampling is the preferred method of sampling under the following conditions:

a.            A snapshot of the wastewater quality at a particular instant in time is desired; and

b.            The water or wastewater stream is not continuous (e.g., batch discharges or intermittent flow);

c.            The characteristics of the water or waste stream are known to be constant or nearly so;

d.            When the waste conditions are relatively constant over the period of discharge.  In lieu of complex sampling activities, a grab sample provides a simple and accurate method of establishing waste characteristics;

e.            The sample is to be analyzed for parameters whose characteristics are likely to change significantly with time (i.e., dissolved gases, bacteria, pH, etc.);

f.            The sample is to be collected for analysis of a parameter such as oil and grease or bacteriologicals where the compositing process could significantly  affect the actual concentration;

g.            Data on maximum/minimum concentrations are desired for a continuous water or wastewater stream; and

h.            Identifying and tracking slug loads and spills.

            3.            If required to be measured, the following parameters shall be measured on grab samples or in-situ.  NOTE:  If the permit specifies a composite sample for any of the above-mentioned parameters, THE PERMIT CONDITIONS SHALL BE FOLLOWED.

      4.      Sampling protocols shall follow those outlined under Surface Water (4.2.3.3.a).

b.            Composite Samples

      1.      A composite sample is a sample collected over time, formed either by continuous sampling or by mixing discrete samples.  Composite samples reflect the average characteristics during the compositing period.

      2.      Composite samples are used when stipulated in a permit and when:

a.            The water or wastewater stream is continuous;

b.            Analytical capabilities are limited;

c.            Determining average pollutant concentration during the compositing period;

d.            Calculating mass/unit time loadings; and

e.            Associating average flow data to parameter concentrations.

      3.      Composite samples may be collected individually at equal time intervals if the flow rate of the sample stream does not vary more than plus or minus ten percent of the average flow rate, or they may be collected proportional to the flow rate.  The permit may specify which composite sample to use, either time composites or flow proportional composites.  The compositing methods, all of which depend on either continuous or periodic sampling, are described in the following discussions.

      4.      Time Composite Sample

a.            Time composite samples are based on a constant time interval between samples.

b.            A time composite sample can be collected manually or with an automatic sampler.

c.            This type of composite is composed of discrete sample aliquots collected in one container at constant time intervals.

d.            This method provides representative samples when the flow of the sampled wastewater stream is constant.  This type of sample is similar to a sequential composite sample (described below).

      5.      Flow Proportional Composite Sample

a.            Flow proportional samples can be collected automatically with an automatic sampler and a compatible pacing flow measuring device, semi-automatically with a flow chart and an automatic sampler capable of collecting discrete samples, or manually.

b.            There are two methods used to collect this type of sample:

      1.      One method collects a constant sample volume per stream flow (e.g., 200 milliliters (ml) sample collected for every 5,000 gallons of stream flow) at time intervals proportional to stream flow.  This method provides representative samples of all waste streams when the flow is measured accurately.  For this reason, it is used frequently.

      2.      In the other method, the sample is collected by increasing the volume of each aliquot as the flow increases, while maintaining a constant time interval between the aliquots (e.g., hourly samples are taken with the sample volume being proportional to the flow at the time the sample is taken).

      6.      Sequential Composite Sample - Composed of discrete samples taken into individual containers at constant time intervals or constant discharge increments.

a.            For example, samples collected every 15 minutes are composited for each hour.

b.            The 24-hour composite is made up from the individual one-hour composites.

      1.      Each of the 24 individual samples is manually flow proportioned according to the flow recorded for the hour that the sample represents.

      2.      Each flow proportioned sample is then added to the composite samples.

      3.      The actual compositing of the samples is done by hand and may be done in the field or the laboratory.

      4.      In most cases, compositing in the field is preferable since only one sample container must be cooled, and then transported to and then handled in the laboratory.

      5.      A 24-hour composite is frequently used since an automatic sampler can easily collect the individual samples.

c.            A variation of the 24-hour composite is to collect a constant volume of sample taken at constant discharge increments, which are measured with a totalizer.  For example, one aliquot is collected for every 10,000 gallons of flow.

d.            Sequential sampling is useful to characterize the waste stream because you can determine the variability of the wastewater constituents over a daily period.  For example, for pretreatment studies you can visually determine when high strength wastes are being discharged to a facility or when heavy solid  loads are being discharged during a 24-hour cycle.  You can measure different pHs throughout the day.  The value of this type of sampling must be weighed against the manpower constraints and sampling goals.

      7.      Continuous Composite Sample - Collected continuously from the waste stream.  The sample may be a constant volume which is similar to the time composite, or the volume may vary in proportion to the flow rate of the waste stream, in which case the sample is similar to the flow proportional composite.

      8.      Areal Composite - A sample composited from individual grab samples collected on an areal or cross-sectional basis.  Areal composites shall be made up of equal volumes of grab samples; each grab sample shall be collected in an identical manner.  Examples include soil or residual samples from grid system points on a land application site, water samples collected at various depths at the same point or from quarter points in a stream, etc.

      4.2.4.4      General Concerns

a.            The sampler must weigh advantages and disadvantages when choosing between the use of grab or composite sampling methods.

      1.      While grab sampling allows observation of unusual conditions that may exist during discharge, such as sudden bursts of color or turbidity, this method is labor intensive and impractical when sampling is performed at many locations over extended periods of time.

      2.      When sampling a large number of locations, the use of automatic samplers is more practical.

a.            Automatic samplers also help reduce human error, specifically in complex sampling activities, such as flow proportional sampling, and reduce exposure to potentially hazardous environments.

b.            The primary disadvantage to automatic sampling is the cost of the equipment and maintenance requirements.  Many automatic samplers in use today are electronically controlled and must be sent back to the manufacturer when a malfunction occurs.

b.            In order to obtain a representative sample, sampling must be conducted where wastewater flow is adequately mixed.  In general these criteria shall be used to evaluate the location:

      1.      A sample should be taken in the center of the flow where velocity is highest and there is little possibility of solids settling.

a.            The sample should be collected at a depth between 40% - 60% of the total depth where the turbulence is maximized.  This means that sample collection should be avoided at the water surface or the channel bottom.

b.            Flow mixing is particularly important for ensuring uniformity. 

      2.      Sampling personnel should be cautious when collecting samples near a weir because solids tend to collect upstream and floating oil and grease accumulate downstream.

      3.      If the sample is not to be tested for volatile organics or will not be affected by stripping of dissolved gases, mechanical stirring may be used or a stream of air may be introduced into the waste stream.

      4.      In sampling from wide conduits, cross-sectional sampling should be considered.  Dye may be used as an aid in determining the most representative sampling point(s).  Note: appropriate Department personnel should be consulted for the type of dye and acceptable protocols.

      5.      If manual compositing is employed, the individual sample bottles must be thoroughly mixed before pouring the individual aliquots into the final composite container.

      6.      f the sample is taken from an effluent tap, allow the tap to run for one - two minutes to allow the settled solids to flush from the line.  Reduce the flow to 500 ml/min before collecting the samples.

c.            Sampling and flow measuring are integrally related.  The sampler must know the wastewater flow variability before a sampling program can be initiated.  Whether to use a flow proportional or time composite sampling scheme depends on the variability of the wastewater flow.  If a sampler knows or suspects significant variability in the wastewater flow or knows nothing about the facility, a flow proportional sample should be collected; otherwise a time composite sample would be acceptable.

d.            Prior to sampling, the flow measuring system (primary flow device, totalizer, recorder) should be examined (see sections on Stage and Flow Measurement in the EPA SOP, Sections 7.6 and 7.8).  If the flow measuring system is unacceptable, the sampler may have to install a flow measuring device.  If the flow measuring system is acceptable, samples can be collected by the appropriate method.

e.            Fill out the information on the sample container tags and on the field sheets completely and carefully.  Improper sample identification results in invalid or unacceptable samples and lost sampling efforts.

f.            Take inordinate care to prevent cross-contaminating samples.  Use properly cleaned sampling equipment.

      4.2.4.5      Sample Equipment Requirements

a.            Manual Sampling

      1.      The types of sampling devices that may be used to collect samples are specified in the next section.  Additional discussions are found the protocols for collection grab samples in surface water (section 4.2.3.3.a).

      2.      IN ALL CASES, the selected sampling equipment shall be compatible with the components to be collected and shall comply with the use and construction restrictions specified in Table 4.1.

      3.      All equipment shall be cleaned using the appropriate protocols specified in Section 4.1.  Sample containers shall be cleaned according to Section 4.4.1 or obtained precleaned from commercial sources.

b.            Automatic Samplers

      1.      A wide variety of automatic samplers are commercially available (e.g., Sigma, ISCO).  Most have the following five interrelated subsystem components:

a.            Sample Intake Subsystem - The sample intake gathers representative samples from the sampling stream. 

      1.      The intake is usually the end of a plastic suction tube which should also be resistant to physical damage from large objects in the flow stream.  Nonleaching tygon tubing is most often used.

      2.      Teflon tubing shall be used under the conditions specified in 4.2.4.5.b.2.b.  The end of this tubing should be fixed to a piece of conduit or a pole bent to hold the sample port in the waste stream at the correct location to get a representative sample.  The tubing shall be supported in such a way that the incoming sample is not contaminated by either the supporting pole or the method of attachment.

b.            Sample Gathering Subsystem - Automatic samplers provide one of three basic gathering methods:

      1.      Mechanical - Mechanical gathering subsystems are usually built into place and include devices such wide/deep channel flow.  Because of the mechanical as cups on cables, calibrated scoops, and paddle wheels with cups.  Although these systems obstruct the stream flow, they take into account site specific considerations, such as high sampling lift and system employed, these units require periodic maintenance.

      2.      Forced Flow - Forced flow gathering subsystems are often built into place as permanent sampling facilities; thus, like the mechanical gathering subsystems, they may obstruct the stream flow.  They also require periodic inspection and maintenance.  However, forced flow subsystems have the advantage of being able to sample at great depths.  In addition, because this gathering system uses air pressure to transport the sample, it may be ideal for sample collection in potentially explosive environments.

      3.      Suction Lift - The suction lift is the most widely used type of sample gathering subsystem due to its versatility and minimal affect on flow patterns.  Suction lifts are limited to 25 vertical feet or less because of internal friction losses and atmospheric pressure.  At least 100 ml should be collected each time the pump is actuated.

c.            Sample Transport Subsystem - The sample is usually transported from the sample intake to the collection bottle by a plastic tube referred to as the sample transport subsystem.  Care should be exercised to avoid sharp bends and twists in the transport line.

d.            Sample Storage Subsystem - The sample storage subsystem can accommodate either a single large collection bottle or a number of smaller collection bottles.

      1.      The total sample volume storage capability should be at least 2 gallons (7.6 liters):  some samplers have a capacity as great as 5 gallons.

      2.      To thermally preserve the samples, storage subsystems must be large enough to provide space for ice to chill the sample during collection (see b.3 below).

      3.      Samples with individual bottles for discrete collection are usually equipped with a cassette which rotates to fill the bottle at the time of sampling.

e.            Controls and Power Subsystem

      1.      The control units allow selection of time or flow compositing method, or continuous sampling method.  The automatic samplers most widely used have encapsulated solid state controls.  This minimizes the effects of unfavorable environments that may be encountered in the field, such as high humidity and corrosiveness.  These units are also sealed so that they may be used with minimum risks in potentially explosive environments.  In addition, sealed units protect the controls if the sampler is accidentally submerged.

      2.      Samplers operating from a power supply are more reliable than battery operated models; however, field conditions often prohibit the use of a power supply.

      2.      Automatic sampling equipment must meet the following requirements:

a.            Sampling equipment must be properly cleaned to avoid cross contamination which could result from prior use (see section 4.1.5 for specific cleaning procedures).

b.            If samples for organics (includes all extractable organics, pesticides, and herbicides and TOC) are to be collected, no plastic or non stainless steel parts of the sampler shall come in contact with the water or wastewater stream:

      1.      Teflon tubing shall be used in the transport subsystem.

      2.      A special sampler base and glass containers may also be necessary for sampling organics.  Consult your owner's manual.

c.            If the preservation requirements for a particular component specify that a sample be thermally preserved, the sampler must be able to keep the samples cool to 4 C during the sampling period.  This is accomplished in the field by using ice or refrigeration units in the sampler.

d.            The sampler must be able to collect a large enough sample for all parameter analyses.  Additionally, split samples may also be necessary.

e.            A minimum of 100 ml should be collected each time the sampler is activated, if a peristaltic pump is used.

f.            The sampler should provide a lift up to at least 20 feet and the sampler should be adjustable so that volume is not a function of the pumping head.

g.            The pumping velocity must be adequate to transport solids and not allow solids to settle.

h.            Pump intake line

      1.      The automatic sampler must provide for line purging after each sample is drawn to prevent contamination of subsequent samples.

      2.      The minimum intake line inside diameter shall be at least 1/4 inch, which is large enough to lessen chances of clogging but small enough to maintain velocity and to avoid solids settling.

i.            Sample transport system

      1.      The tubing should be at least 1/4 inch inside diameter to maintain adequate flow and to prevent plugging.

      2.      Tubing should be sized so that a velocity of at least two feet per second can be maintained.

      3.      Line must be automatically purged after each sample is collected.

j.            An adequate power source should be available to operate the sampler for 48 hours at a 30-minute sampling interval.

k.            Sample collection vessels large composite or discrete sample containers, shall be constructed of materials appropriate for the tests to be performed.  As a general rule, the vessels shall be made of the same material as those specified for sample containers in section 4.4.2.3.

      3.      In addition to the requirements listed in 4.2.4.5.b.2 above, several factors should be considered in selecting automatic sampling equipment.  Among these are:

a.            Convenience of installation and maintenance - Sampling equipment should always be handled carefully and maintained in accordance with the manufacturer's instructions.  Most equipment failures are caused by careless handling and poor maintenance.

b.            Equipment security

      1.      Security is important when sampling is done as part of an enforcement proceeding.

      2.      Manhole locations where battery operated equipment may be installed and the cover replaced will aid in maintaining security.

      3.      If sampling equipment must be left unattended, the sampler should be provided with a lock or seal which, if broken or disturbed, would indicate that tampering had occurred.

c.            Operation in cold or hot weather

      1.      Cold weather - In Florida, use of automatic samplers is seldom a problem during cold weather.  If a sample must be taken during extremely cold days freezing of intake lines may happen.  These problems may be handled by using heat tape or placing the sampler inside a thermostatically controlled, electrically heated enclosure.  In the absence of special equipment, freezing may be prevented by installing the sampler in a manhole or wet well or by wrapping the sampler with eight or nine inches of insulation and wind protection.  Also, the sampler should be positioned well above the effluent stream so that the tubing runs in a taut, straight line to prevent pooling of liquid.

      2.      Hot weather - The summer heat in Florida does pose a significant problem with keeping the sample cool.  If possible, choose a shaded or even cooled place for the sampler.  If not, insulation wrapped around the sampler may help.  Painting the sampler white will reflect some heat.  Before leaving the site refill the automatic sampler with ice or check to see that the refrigeration unit is operating.  An attempt should be made to pick up the samples near the time the last sample is taken.  Samples which are allowed to warm up are questionable, if not useless.

      4.2.4.6      Sample Acquisition

a.            Manual Sampling

      1.      Manual sampling is used for collecting grab samples for immediate in-situ field analyses.  However, it can also be used in lieu of automatic equipment over extended periods of time for composite sampling, especially when it is necessary to observe and/or note unusual waste stream conditions.

      2.      Collection using the Sample Container

a.            The actual sample container must always be used for collecting samples for oil and grease, volatile organic compound (VOC), and bacteriological samples.

b.            If possible, manually collected samples should be collected in the actual sample container that will be submitted to the laboratory.  This eliminates the possibility of contaminating the sample with an intermediate collection container.

c.            Sample containers containing premeasured amount of preservatives SHALL NOT be used to collect surface water grab samples.  Alternative collection procedures listed below must be followed.

d.            Sample collection shall follow the protocols for collecting simple grab samples in surface water (Section 4.2.3.3.a).

      3.      Sampling with an intermediate vessel or container

a.            If the sample cannot be collected as described above, an intermediate vessel can be used.

b.            The sample shall be collected following the protocols described for collecting surface water grab samples with an intermediate container or pond sampler (Section 4.2.3.3.a) and redistributed into appropriate sample container(s).

            4.            Samples collected in bailers

a.            Bailers may be used if the data requirements do not necessitate a sample from a strictly discrete interval of the water column.

b.            Bailers with an upper and lower check-valve can be lowered through the water column and water will be continually displaced through the bailer until the desired depth is reached, at which point the bailer is retrieved.  This technique may not be successful in strong currents.

c.            Specific sampling protocols outlined under mid depth surface water sampling (4.2.3.3.b.4) shall be followed.

5.      Samples collected with pumps

a.            In some cases it may be best to use a pump, either power or hand operated, to withdraw a sample from the water or wastewater stream.

b.            Protocols for the use of pumps are specified in the surface water sampling Section (4.2.3.3.b.5) and shall be followed when collecting with pumps.

      6.      Dedicated equipment may also be used at each sampling station.  This will avoid cross contamination between sampling stations.  For most parameters (other than trace metals and organics) rinsing the sampling device three times in the effluent stream is sufficient.  More stringent requirements must be used for trace pollutants (see Section 4.1).

b.            Automatic Samplers

      1.      Automatic samplers may be used when several sites are to be sampled at frequent intervals or when a continuous sample is required.

      2.      Conventional Sampling:  All composite samplers can be used to collect time composite or flow proportional samples.

a.            In the flow proportional mode, some samplers are activated by a compatible flow meter.

b.            Flow meter operation will not be discussed here. Refer to the operating manuals if you have them.

c.            For older models, flow proportional samples can be collected using a discrete sampler and a flow recorder and manually compositing the individual aliquots in flow proportional amounts.

            3.            Installing the Composite Sampler

a.            All new or precleaned tubing (Dow Corning Medical Grade Silastic, or equal, in the pump and either Teflon or Tygon, depending on the parameters of interest, in the sample train) shall be used each time the sampler is installed.

      1.      Cut the proper length of precleaned Teflon or Tygon tubing;

      2.      Rinse deionized water through the sampler and collect an equipment blank;

      3.      Put the collection sieve and tubing in the appropriate sample location in the wastewater stream, using conduit if necessary to hold it in place.  Assure that the incoming sample water is not contaminated by the supporting conduit; and

      4.      Program the sampler as per manufacturer's directions and as required in the permit conditions.

b.            For a time composite sample, the sampler should be programmed to collect 200 ml at 30-minute intervals or 100 ml at 15-minute intervals into a refrigerated 3-gallon jug.  For a 5-gallon compositing jug, the volume should be increased accordingly.

c.            For a flow proportional sample, the sampler should be programmed to collect a minimum of 100 ml for each sample interval, with the interval predetermined based on the flow of the waste stream.

d.            At the end of each 24-hour sampling period, the contents of the compositing jug (sample) should be stirred and siphoned (poured if no visible solids) into the respective containers, followed by immediate preservation, if required.

      4.      Automatic Sampler Security -  A lock or seal may be placed on the sampler to prevent or detect tampering.  However, this does not prevent tampering with the sampler tubing (see additional discussions on sample security under equipment requirements 4.2.4.5.b.3 above)

      5.      Sample Preservation - Samples shall be preserved for all samples according to 40 CFR Part 136 Table II.

a.            Table II includes allowances for automatic samplers.  In addition to the capability of keeping samples cooled with ice or refrigeration, there are 2 considerations to be presented for chemical preservation:

      1.      If separate bottles are used, they may be prepreserved with the appropriate chemical preservative or preserved after sampling has been completed (WITHIN 24 HOURS);

      2.      If the large compositing jug is used, preservation should be completed after sampling has been completed (WITHIN 24 HOURS);

      3.      NOTE: If the only parameter of interest is Total Phosphorus, and the project is unrelated to a NPDES permit, then the sample must be chemically preserved (H2SO4) but it need not be cooled to 4 C with wet ice.  The acid must be in the container prior to sample collection.

4.2.5            Groundwater Sampling

      4.2.5.1      Introduction and Scope

      This section presents the standard operating procedures that should be employed during field investigations to ensure that representative groundwater samples are collected.  The importance of proper sampling of monitor wells cannot be overemphasized.  Care should be taken so that the sample collected is neither altered nor contaminated by sampling and handling procedures.

      The following discussions cover acceptable: equipment choice, equipment construction materials, pre-sampling and in-field decontamination, purging and sampling technique, and proper field Quality Control procedures.  Although not a complete discussion of all groundwater sampling procedures, this information has been

compiled with the intent of providing the equipment and techniques for situations that are most likely to be encountered.

      [[4.2.5.2      Selection of Sampling Materials

      This section is intended as a GUIDE to be used when selecting sample collection and/or well purging equipment.  The discussions are informational and should be considered as criteria when selecting equipment.

      The selection of inert materials used for well purging, sample collection, handling and storage is a critical consideration in planning the well-conceived cost-effective monitoring program.  These equipment descriptions may also be used for other sampling matrices.  The materials of choice should retain their structural integrity for the duration of the monitoring program.  They must not react with the sample (i.e.,  should not absorb, adsorb or leach sample constituents) which would bias representative sample collection.  Additionally, the sampling equipment should be chosen so that they can be easily decontaminated and transported.  The following subsections, adapted from Barcelona, et al. (1983) and Watts (1988), discuss sampling material construction.

a.            Stainless Steel - The most common types of stainless steel that are used in sample collection equipment are 316 and 304 although other types are available and may be used.

            1.            Stainless Steel-316

a.            Recommended for use in most groundwater and soil monitoring situations for all parameter groups.

b.            Stainless Steel-316 should be utilized especially for detailed organic and trace metals analytical work.

c.            Stainless Steel-316 is least likely to introduce sampling bias or imprecision.

d.            Stainless Steel-316 is also relatively easy to decontaminate without requiring a HNO3 rinse.

e.            The cost per foot of Stainless Steel-316 is approximately the same as Teflon.

f.            Note that dedicated stainless steel sampling equipment (tubing, submersible pump housing, etc.) may not be suitable to collect samples for metals analyses since its performance may be sensitive to the chloride ions, which can cause pitting and corrosion over long term exposure under acidic conditions.

            2.            Stainless Steel-304

a.            Recommended for use in most groundwater and soil monitoring situations for all parameter groups (including trace organics and metals). 

b.            Stainless Steel-304 is less corrosion-resistant than 316 and may be prone to show pitting and corrosion if left in contact with acidic high total dissolved solids (TDS) groundwaters for extended periods (dedicated downhole equipment).

c.            Corrosion products are mainly limited to iron and potentially Cr, Cu and Ni.  Pitted surfaces may present active adsorption sites and render difficulty in future decontamination.

c.            Teflon

      1.      Teflon is the trademark of Dupont, Inc.  Teflon is recommended for use in most groundwater and soil monitoring situations for all parameter groups, especially for detailed, trace organic analytical work.

      2.      Teflon material is least likely to introduce sampling bias or imprecision.  Teflon is relatively easy to decontaminate.  Teflon is a relatively soft material and is easily scratched.

      3.      Bailers and tubing that are old and excessively scratched will be difficult to clean and must be discarded.

      4.      Some Teflon bailers have replaceable "donuts" that encircle the bailer and protect the body from scratches.

d.            Low-Carbon Steel, Galvanized Steel and Carbon Steel

      1.      These materials are generally not recommended for collecting samples, especially galvanized steel.

      2.      In cases of split spoon and core barrel soil sampling these might be the only material available.

a.            If trace metals are of interest, plastic or teflon liners shall be used to prevent the sample from contacting the equipment surface.

b.            Teflon liners are recommended if organics are of interest.

      3.      New equipment made from these materials must be very carefully cleaned to remove oily manufacturing residues.

      4.      Corrosion is likely in high dissolved solids and acidic environments, particularly when sulfides are present.

      5.      Products of corrosion for carbon steel are mainly Fe and Mn, except for galvanized steel which may release Zn and Cd.

      6.      Weathered steel surfaces present very active adsorption sites for trace organic and inorganic chemical species and pitted surfaces will increase the difficulty of decontamination.

e.            Polypropylene/Polyethylene

      1.      Polypropylene and polyethylene are polyolefin materials that are more resistant to organic solvent attack than formulated plastics such as Viton, silicone or neoprene.

      2.      Polypropylene and polyethylene are comparable in performance and resistance to Teflon in corrosive high dissolved solids (Pettyjohn et al., 1981 and Barcelona et al., 1983).

      3.      Polypropylene and high density polyethylene (HDPE) tubing material may be used for purging wells (see Table 4.1 for details).

      4.      HDPE disposable bailers may be used to sample all parameters except organic compounds.

f.            Polyvinyl chloride (PVC)

            PVC (flexible) is not recommended for detailed organic analytical work.  The polymer formulated PVC contains plasticizers, stabilizers and antioxidants which may cause interferences with analytical determinations, especially when industrial solvents are encountered in groundwater.  Documented interferences are likely with several priority pollutant classes. 

g.            Viton, Tygon, Silicone and Neoprene

            Viton, Tygon, silicone and neoprene are not recommended for organic analytical work since the inherent plasticizers, stabilizers and antioxidants may introduce interferences.]]

      4.2.5.3      Purging and Sampling Equipment

a.            General Considerations

      1.      Purging the monitor well of stagnant water can be performed with various equipment.  The choice of equipment will depend on the parameters of interest, the well diameter, the well specific capacity, transmissivity, the water level elevation and other site conditions.  As stated earlier, the choice of equipment used for purging must not bias the "representativeness" of the sample collected.

      2.      It is recommended that field personnel use pumps to purge monitor wells if at all possible.

      3.      Bailers are not recommended for purging monitor wells because frequent lowering and retrieving of the bailer:

a.            will introduce atmospheric oxygen which may precipitate metals (e.g. iron) or cause other changes in the chemistry of the formation water (i.e. pH),

b.            will result in agitation or volatilization of groundwater which may bias volatile and semi-volatile analyses, and

c.            may introduce dirt through scraping the sides of the casing wall.

      4.      Though bailers are not recommended for purging, they are acceptable if constructed of the appropriate material and if extreme care is used.  The use of bailers is described in 4.2.5.3.c below.

      5.      All standing water around the top of the well casing (manhole) shall be removed before opening the well.

b.            Pumps - A summary of the principles of operation and  the advantages and disadvantages of the various commercial pumps is given in "Monitor Well Construction and Groundwater Sampling" (Watts, 1988).

            1.            Above-ground Pumps

a.            Peristaltic Pump - Peristaltic pumps may be used to purge low volume, low specific capacity wells in which the static water level in the well is no greater than 20-25 feet BLS (Below Land Surface).

      1.      Decreased pumping velocity will be experienced when water levels are deeper than 18'-20'.

      2.      It also may be used to sample wells for limited parameter groups.  These parameter groups will be dependent upon tubing materials and arrangements.  It is the preferred method of collecting filtered groundwater samples for metals.  See Table 4.1 for details on the restrictions for this pump, including choice of tubing (i.e. Teflon, HDPE, Tygon).  See EPA Region IV SOP & QAP, Appendix F.1 for additional guidance.

b.            Centrifugal Pump - Centrifugal pumps can be utilized to purge 2 inch and larger internal diameter wells that have moderate specific capacities from 2 - 10 gpm (gallons per minute) and have a static water level greater than 20 feet BLS.

      1.      The pump may also be attached directly to 3/4" well point casing and used to purge (see 4.2.8, care must be taken so that purged water does not fall back into the well casing).

      2.      Sampling gloves shall be worn and discarded after positioning the pump.  Hands should be washed and new gloves shall be put on prior to sampling.

      3.      See Table 4.1 for compatibility restrictions related to choice of tubing and allowable parameter groups.

            2.            Submersible Pumps

a.            Electric Submersible Pumps - Submersible pumps (e.g. Grundfos, Goulds, Jacuzzi) can be utilized for purging 4 inch or greater diameter monitor wells.  Some submersible pumps can be utilized in 2 inch wells (e.g. Fultz and Grundfos).  These pumps can be used in wells that have moderate to high specific capacity and cannot be purged using an above-ground pump because of the lower static water level elevation (>20'-25' BLS).

      1.      The pump must be constructed of stainless steel (and/or Teflon) material and the delivery hose shall be constructed of appropriate material depending upon the analytes of interest.

      2.      It may be fitted with inert stainless steel or Teflon tubing between the pump and "other non-inert tubing" to be able to purge wells that will be sampled for trace organics.

      3.      See EPA Region IV SOP & QAM, Appendices F.2-F.3 for further information regarding 2 and 4 inch electric, submersible pumps.

b.            Bladder Pumps - Positive-displacement bladder pumps (no-gas contact) can be utilized for purging wells where the water table is greater than 25 feet and an above-ground pump cannot be used.  These pumps are used in wells with low to moderate capacity since pumping rates are not as high as the electric submersibles or the gas-contact "purge pump" described below.  Maximum pumping rates are approximately 0.5 - 1.5 gallons per minute depending upon the location of the pump (BLS).

      1.      The bladder pump system is composed of three major components:  the pump, the compressed air and water discharge tubing, and the controller/compressor.

      2.      The pump consists of a bladder and an exterior casing or pump body that surrounds the bladder.  These two parts can be composed of various materials, usually combinations of PVC, Teflon, and stainless steel.

      3.      The construction material of the pump body, pump bladder, and the discharge tubing will define the parameters that can be purged and sampled with this system.

      4.      If the pump is not permanently installed in the monitor well and if it is to be used to purge and/or sample for all parameters (including VOCs), the pump, bladder and tubing must be constructed of stainless steel and Teflon.

      5.      Permanently installed pumps have a PVC pump body as long as the pump remains in contact with the formation water.  If VOCs and/or extractable organics are of interest, the bladder and the delivery tubing shall be constructed of teflon.

c.            Bladderless Purge Pumps - These pumps are identical to the bladder pumps described above except they do not have an internal bladder.  The air controller/compressor is used to force water from within the pump body up the discharge tubing.  By not having the (Teflon) bladder fill by head pressure, pumping rates are much higher (>4 gpm).

      1.      This pump can only be used for purging.

      2.      Additionally, operation of this pump cannot result in purge water escaping back into the well.  Proper operation and maintenance of the check valve must be ensured.  Release of aerated purge water into the water column is not acceptable.

            3.            Hand Pumps

a.            Hand pumps (e.g. Brainard-Kilman 'B-K Pump') are manual pumps that should be utilized for purging 2- or 4-inch diameter monitor wells in which the static water level is too deep for use of a centrifugal or peristaltic pump.

      1.      The B-K hand pump and the associated riser pipes are constructed of PVC and shall be used to purge when only inorganic constituents are of interest unless the restrictions specified in Table 4.1 are followed.

      4.      The lower most section of the B-K pump is equipped with a foot valve to prevent back flow of purge water.

      5.      After purging has been completed, the B-K pump should be completely disassembled and decontaminated.

      6.      Please see Table 4.1 for details on the use of this pump.

c.            Bailers

      1.      As stated above, the use of bailers is not recommended for purging.

      2.      Bailers shall be composed of material compatible with the analytes of interest.  See Table 4-1 for restrictions

a.            Bailers constructed of stainless steel and Teflon may be used to sample any and all parameters.

b.            Bailers constructed of high density (rigid) polyethylene (HDPE) materials may be used to sample monitor wells for inorganics and free-product only.

c.            When sampling grossly contaminated tanks or other facilities, disposable polyethylene (or other material) bailers should be utilized (it may be difficult to decontaminate such grossly contaminated bailers and as such they may have to be discarded).

      3.      The bailer must be handled carefully so as not to contaminate it prior to use.

      4.      They shall be scrupulously cleaned, including all check valves (see Section 4.1.4.1).

d.            Lanyards

      1.      Lanyard may be disposable (braided or monofilament nylon or reusable (stainless steel or teflon-coated).

      2.      A disposable lanyard must be changed for each monitor well, but the same lanyard may be used for purging (if performed) and sampling operations without decontamination between purging and sampling operations.

      3.      Reusable lanyards shall be decontaminated between monitor wells (see Section 4.1.9.1) but do not require cleaning between purging and sampling operations.

      4.2.5.4      Water Level and Purge Volume Determination

      Prior to sampling, an adequate amount of stagnant well water in the well must be removed in order to sample representative formation water.

a.            Inspect the exterior protective casing monitor well for damage and document accordingly.

b.            Water Level Measurements

      1.      In order to calculate the purge volume, the water level is determined by using an electronic probe, chalked tape, etc.

      2.      The depth below land surface shall always be recorded to the nearest 0.1 foot from the same reference or survey mark on the well casing.

      3.      Measurements using an electronic probe shall follow the manufacturer's instructions.  Since false reading may be obtained if the sensor contacts the well casing, multiple readings shall be taken to ensure accuracy.

      4.      Chalked Tape Method

a.            Lower chalked tape into the well until the lower end is in the water (usually determined by the sound of the weight hitting the water).

b.            Record the length of the tape relative to the reference point (see 2 above).

c.            Remove tape and note the length of the wetted portion.

d.            The depth to water is determined by subtracting the length of the wetted portion (c above) from the total length (b. above).

      5.      Decontaminate all measuring devices immediately after use (see 4.1.9.1) and prior to next measurement.

c.            Water Column Determination

      1.      The total water column is obtained by subtracting the depth to the top of the water column from the total depth of the well.

      2.      Total depth of well is dependent upon the well construction.  Some wells may be drilled in areas of sinkhole or karst formations.  In cases where there may be an open borehole below the cased portion, an attempt should be made to find the total borehole depth.

d.            Well Water Volume

            The length of the water column is then converted to volume of water that is present in the well:

      1.      2 inch casing:

            V = 0.17 X h

            Where:  V = volume in gallons

                           h = height of the water column in feet

      2.      4 inch casing:

            V = 0.66 X h

            Where:  V = volume in gallons

                           h = height of the water column in feet

      3.      For other casing sizes, calculate using the following:

            V = (0.041)d X d X h

            Where:  V = volume in gallons

                           d = well diameter in inches

                           h = the height of the water column in feet

      or:

            V = Pr X r X h(0.001)

            Where:  V = volume in liters

                           P = 3.14159 (pi)

                           r = radius in centimeters

                           h = height of water column in centimeters

e.            Record all measurements in the field records.

      4.2.5.5      Well Purging Techniques

      To ensure a representative groundwater sample from a monitor well it is essential that the well be purged prior to sampling.  Stagnant water in a well casing may undergo a variety chemical changes due to alterations in the redox potential, pH and leaching of organic compounds from the casing.

      Several methods of purging wells have been cited in the literature (Gibb et al., 1981, and Barcelona et al., 1983).  The choice of purging technique may be dictated by hydrogeologic properties (particularly depth to water table and hydraulic conductivity).

a.            Equipment selection shall comply with construction and configuration requirements specified in Table 4.1.

b.            A clean protective covering may be placed around the wellhead during purging activities.  If this protective covering becomes soiled, ripped, etc. it must be replaced prior to sampling.

c.            The total amount of water must be recorded.  Therefore, the volume must be measured during the purged operation.  The amount may be determined by:

      1.      Collecting the water in a graduated container (i.e. bucket); or

      2.      Calculating volume based on pumping rate.  Note:  the pumping rate may not be constant; take this into account.

d.            Record the time that actual purging begins in the field records.

e.            Purging is considered complete if any one of these criteria are satisfied:

            1.            three well volumes and subsequent stabilization of field parameters

a.            Stabilization of field parameters is defined as "consecutive readings within 5% taken at least five minutes apart". 

b.            Even if field parameters have not stabilized after 5 well volumes, purging is considered complete and sampling can begin.

            2.            five well volumes (field parameters not monitored);

            3.            at least one fully dry purge.

a.            It has been suggested that one dry purge may not be adequate and a second dry purge may be necessary.  Theories concerning purging the sandpack or aeration of sandpack will not be discussed here.

f.            Except for "low recovery" wells, all wells shall be sampled within 6 hours of purging.

      1.      "Low recovery" wells or wells that have been purged complete dry may be sampled as soon as sufficient sample matrix is available or up to 10 hours after purging.

      2.      Wells that have not recovered sufficiently within 10 hours of purging should not be sampled.

g.            Lanyards

      1.      All lanyards must be securely fastened to downhole equipment (bailers, pumps, etc.).

      2.      Equipment construction and decontamination shall follow guidelines discussed in Purging and Sampling Equipment above (4.2.5.3.d).

      3.      Bailer lanyards must be handled such that they do not touch the ground surface.

h.            Low Hydraulic Conductivity Monitor Wells (i.e. wells that can be purged dry)

      1.      The most straightforward method for removing all of the stagnant water in wells screened in low hydraulic conductivity formations is to install the pump in the screen area and pump the well dry.

      2.      Although this procedure may allow the atmosphere to contact the area of the aquifer immediately surrounding the well screen, it is the best way to ensure that all the stagnant water has been removed.

      3.      If required, allow the well to recover and purge the well a second time.

i.            High Hydraulic Conductivity Wells (i.e. wells that cannot be purged dry)

      1.      For those wells with dedicated purging/sampling systems where the pump is set in the screened area of the well, complete evacuation of the stagnant water column may not be possible.

      2.      The degree to which the stagnant water column can be replaced by fresh aquifer water will be a function of the aquifer transmissivity and the number of well volumes pumped (Barcelona et al., 1983).

      3.      If in doubt, a short pump test or slug test may be performed on each monitor well and the number of well volumes calculated to assure replacement of the stagnant water.

j.            In general, when nondedicated pumps that are used for purging, the purging process should be done with the pump as near to the top of the water column as possible to ensure that no stagnant water remains in the well above the screen after purging.

k.            Peristaltic Pump - One end of a length of new or pre-cleaned tubing shall be attached to the pumphead flexible hose and the other end immersed no deeper than one foot into the water column.

l.            Centrifugal Pumps

      1.      To minimize cross contamination while purging, fuel driven centrifugal pumps must be placed at least 10 feet from the well head and downwind of the well.

      2.      Sampling gloves shall be worn and discarded after positioning the pump.  Hands should be washed and new gloves shall be put on prior to sampling.

      3.      The length of suction hose should be situated such that the pump will be withdrawing water from the top of the column.

      4.      If the pump rate exceeds the recovery rate of the well then the hose should be lowered into the well as needed to accommodate the drawdown.

      5.      The suction hose must have a footvalve installed to prevent purge water from re-entering the well.

m.            Electric Submersible Pumps

      1.      The pump should be set as near the top of the water column as possible to ensure that all stagnant water in the casing is removed and to minimize the contact area of the delivery hose with water column.

      2.      If the pump rate exceeds the specific capacity of the well then the pump must be lowered to accommodate the drawdown.

      3.      If the pump has a controller, the flow rate may be adjusted to be equal (or nearly) to the well's pumping capacity.

n.            Bladder Pumps

      1.      This equipment shall be operated strictly according to the owners/operators manual or sample integrity and representativeness may be suspect.

      2.      After determining water level, position the controller/compressor away from the well and downwind (if fuel powered compressor or generator).

      3.      Attach tubing and lower the pump to a depth of 3 - 5 feet below the surface of the water.

      4.      If the pump is positioned too deep all of the stagnant water may not be purged.  If positioned too shallow purging time will be slower as the bladder fills under standing head pressure.

      5.      Adjust the pump position to follow the water level drawdown, if necessary.

      6.      It may be necessary to adjust the purging rate so that it is equivalent to the drawdown rate.

      7.      Discharge must be directed into graduated bucket or equivalent to determine the number of well volumes.

o.            BK Hand Pump

      1.      For the B-K Pump, the intake is lowered to the top of the water column by attaching additional 5-foot sections onto the pump.

      2.      By changing the stroke of the actuating rod the pumping rate can be made compatible with the well-specific yield.

p.            Bailers

      1.      The bailer must be handled carefully so as not to contaminate it prior to use.

      2.      The bailer must be lowered through the well and into the formation water slowly.  Allowing the bailer to drop into the formation water with a splash is not acceptable.

      3.      The bailer should be used to pull purge water from the top of the water column so that fresh aquifer water can be pulled in through the screen.  This technique shall be performed until the requisite number of well volumes have been evacuated.

q.            All purging activities shall be documented in the field notes.  See Section 5.5 for the specific information that must be included.

      4.2.5.6      Groundwater Sampling Techniques

a.            Equipment Considerations

      1.      Some pumps may be used for sampling groundwater.  All notes and restrictions as defined in Table 4.1 and discussed in Purging and Sampling Equipment (Section 4.2.5.3) shall be followed when using pumps to collect samples.

a.            NOTE:  The only pump that is currently approved for use in collecting volatile samples is an all stainless steel and teflon bladder pump.

      2.      Other than the actual sampling device, intermediate vessels should not be used during the sample collection process.  This is especially true of any compound where loss of sample is a problem (O&G, TRPH and VOCs).  For all trace compounds, the sample should come in contact with as few surfaces or vessels as possible since excessive handling can result in contamination or sample loss.

      3.      Dedicated Sampling Equipment

a.            The use of dedicated equipment is recommended since it significantly reduces the chance of cross-contamination.

b.            Dedicated is defined as equipment that is to be used solely for one location for the life of that equipment (permanently mounted pump or permanently dedicated bailer).  Bringing 5 bailers on site to sample 5 monitor wells does not constitute dedication UNLESS the bailers were purchased for the project, and each bailer is specifically assigned to purge and/or sample a particular well.

c.            All material construction and restrictions from Table 4.1 also apply to dedicated equipment.  Equipment should be purchased with the most sensitive analyte of interest in mind.

d.            Cleaning/Decontamination

      1.      Dedicated pumps shall be cleaned prior to installation.  They need not be cleaned prior to each use but should be cleaned when they are withdrawn for repair or servicing.

      2.      Any permanently mounted tubing need not be cleaned.

      3.      Any replaceable or temporary tubing shall be cleaned as specified in Section 4.1.7.

      4.      Equipment blanks on dedicated pumps shall be required when the tubing is cleaned or replaced and shall be collected through that portion of the tubing that is accessible.

      5.      Dedicated bailers, if stored in the well, must be suspended above the water column and completely decontaminated between sampling events.

a.            After sampling is complete, they shall be rinsed with tap water and/or analyte-free water, wrapped to prevent contamination, and stored on- or off-site until the next sampling event.

b.            The sampling equipment shall be decontaminated prior to on-site arrival UNLESS the equipment is stored on-site.  In the latter case, the dedicated bailer shall be fully decontaminated prior to on-site use.

c.            A precleaned equipment blank shall be collected prior to reintroducing the cleaned bailer into the water column.

b.            Sampling with Bailer

      1.      When a bailer is used for sampling, the integrity of the sample collected is highly dependent upon the sampler's skill and familiarity with proper sampling techniques.

      2.      It is recommended that for a particular site only two persons perform sampling to minimize personnel handling variation.

      3.      Just prior to sampling, several bailer amounts of sample groundwater shall be collected to rinse the bailer.

a.            Discard the water appropriately (see Waste Disposal).

b.            This should not be done if the analytes of interest include Oil & Grease, TRPH, etc. (see Section 4.0.3).  As stated earlier, intermediate vessels or sampling equipment are never rinsed if these compounds are to be sampled.

      4.      All collection activities shall be done carefully so as to not stir up any sediments.

      5.      The following procedure describes general bailing techniques:

a.            Field personnel should wear protective gloves (see Section 4.0.2).

b.            Attach a fresh length of monofilament or braided nylon line to the bailer.  Alternately, a precleaned permanent lanyard may be used.

c.            The bailer or lanyard must not be allowed to touch the ground during purging or sampling.

d.            Lower the bailer slowly and gently into contact with the water so that agitation of the water column is minimized.

e.            Attempt to sample from the same depth in the well each time, preferably within or just above the screened zone of the well.

f.            Do not allow the bailer to touch the bottom of the well so that bottom sediment is incorporated into the sample.

g.            Retrieve the bailer smoothly.  Collecting the lanyard between the thumbs of each hand seems to be the preferred method.

h.            Discard the first few inches of water in the bailer and fill the appropriate sample bottles so that a minimum of turbulence is created to avoid aeration.

I.            Discard the last few inches of water in the bailer.

j.            Add preservatives (if necessary), check the pH of all pH-adjusted samples (except VOCs).

k.            Attach and/or complete the sample container labels, record information in field notes, place samples on wet ice (if required) and protect all samples from sun.

      6.      Sampling with disposable bailers, though acceptable, is not recommended as a standard procedure for environmental sampling.

a.            Disposable bailers of the appropriate construction material are available.  High density polyethylene (HDPE) bailers are acceptable for all inorganic parameters (and free product thickness).

b.            Teflon bailers are also available as a disposable for use where organics are of concern.

c.            As the agency charged with solid waste management as well as environmental sampling and analysis, the Department cannot encourage the use of disposable equipment for all situations.  In situations where expensive, permanent sampling equipment may be destroyed or damaged by sampling a concentrated waste, the used of disposable equipment is recommended.

d.            Precleaned equipment blanks are required for disposable equipment (see Quality Control for frequency).

c.            Sampling with Pumps

            As a general rule, pumps shall not be used to collect samples if organics are of interest.  There are two exceptions:  1) use of the peristaltic pump with a trap (see Fig. 4.1 for specific configuration) for EXTRACTABLE organics; and 2) use of an all Teflon and stainless steel bladder pump for all organics.

            1.            Peristaltic Pump

a.            Organics

      1.      Assemble the components of the pump according to the Fig. 4.1.

      2.      The container shall be a glass or teflon bottle.  The sample container is recommended, however, if an intermediate vessel is used, it shall be decontaminated between wells per Section 4.1.4.1.

      3.      All equipment that contacts the groundwater BEFORE the sample container shall be of Teflon, stainless steel or glass construction, including the transport tubing to and from the sample container, the interior liner of the container cap and all fittings.  UNDER NO CIRCUMSTANCES CAN A RUBBER STOPPER BE USED AS THE CAP.

      4.      Connect the outflow tubing from the container to the influent side of the peristaltic pump.

      5.      Turn the pump on and allow the container to fill approximately 1/4 full.

      6.      Turn the pump off, disconnect the container, rinse the bottle and discard the contents.

      7.      Repeat the process a second time.  Note restrictions on rinsing in Section 4.0.3.

      8.      Turn pump on to fill the container.

      9.      If an intermediate container is used, distribute the sample into appropriate containers.

      10.      If the sample container is used, discard a  small portion of the sample, to allow an air space.

      11.      Preserve (if required), label and complete field notes.

b.            Inorganics

      1.      Inorganic samples may be collected from the effluent tubing, and there are few restrictions on tubing type (see Table 4.1).

      2.      If samples are collected from the pump, all tubing (including the tubing in the head) shall be changed between wells.

            2.            Bladder Pump

a.            The flow rate shall be reduced after purging to a smooth, even flow.

b.            When sampling for VOCs, the flow rate must be reduced to 500 ml/minute (approx. 0.1 gallon/min).

            3.            Other pump types

a.            Sampling for INORGANICS ONLY may be conducted with most other pump types (see Table 4.1).

b.            The flow rate during sample collection shall be a smooth even flow.

c.            All tubing and the pump shall be decontaminated between wells.

d.            Sampling Wells that have Free-Phased Product

      [[1.  The Department does not recommend the sampling of wells with free floating product for trace contaminants.  This concerns primarily petroleum related sites, but includes any chemical product (e.g. solvent) that floats on the water table.  Sampling is acceptable if the information is to be used for the purpose of remedial design.

      2.      Sample data from such wells cannot provide useful information regarding the level of contamination.  Furthermore, the Department believes that these wells may never provide legitimate data as they may have become (permanently) chemically damaged by the product being in contact with the well casing for an extended period of time.

      3.      The Department does reserve the right to require sampling of these wells, not for levels of trace contaminants, but for confirmation of an appropriate remediation technique.  This type of sampling is performed BELOW the product layer (see 4.2.5.6.f. below).]]

e.            Free Product Sampling

            1.            Free product is normally sampled for two reasons:

a.            documentation for its existence (and thickness), as required in the Tanks regulations; and

b.            determination of the type of product so that the proper analyses can be performed to determine extent.  This is only feasible for relatively recent releases as weathered product may not be able to be identified.

      2.      Free product may be evident in a cased monitor well or an open excavation.

      3.      It is recommended that plastic (acrylic, clear PVC) bailers be used for sampling the monitor wells.  Optionally, disposable (HDPE) bailers are acceptable.  Other wide-mouth vessels may be used for sampling the excavation.

a.            Monitoring well:

      1.      If free product (defined in 17-770 as product in excess of 0.1 inch) or product globules are present in a monitoring well, a precleaned bailer is used to collect the sample.

      2.      Once the bailer is withdrawn product thickness is measured to the closest 0.1 inch.

      3.      A portion of the product is poured into a glass vial.

      4.      As a concentrated waste, this sample must be wrapped to prevent breakage, isolated from other samples, iced to 4 C, and proper chain of custody information completed.

b.            Excavation:

      1.      If free product is observed in an open excavation, the glass sample container or a precleaned intermediate vessel may be used to collect the sample.

      2.      A lanyard (e.g. braided nylon) is tied to the container and lowered into the excavation.

      3.      Care must be taken not to introduce solid material into the container as it is being lowered or retrieved.

      4.      If sufficient water is available, a bailer can be used.

      5.      Though not recommended, screened casing can be placed (or augured and placed) in the bottom of the excavation and sampled with a bailer.

      6.      Avoid dangerous situations, such as standing too close to the edge of an excavation, riding in the backhoe bucket, or entering a trench or excavation that may collapse.

      7.      All applicable OSHA regulations should be followed.

      4.      Equipment which is dedicated to sampling free product does not need to be cleaned according to the standard, full decontamination protocols.  Acrylic or PVC bailers that are never used for trace contaminant sampling may be cleaned as listed below.  It is recommended that all cleaning be done in the lab, office, or base of operations and not in the field.

a.            disassemble bailers and intermediate vessels and soak in hot, soapy tap water using a brush to clean away all particulates and greasy films,

b.            rinse with hot tap water,

c.            thoroughly rinse with DI water

d.            An optional acid rinse may be used to strip the equipment of any hard to clean residues.

e.            The solvent rinse is not mandatory since this equipment is not used for contaminant sampling, other than the product itself.  It is not recommended on clear acrylic.

f.            Sampling Below Product

      1.      This type of depth-specific sampling is performed only at the request of DER or its designee.  An attempt is made to sample the dissolved constituents in the water column below the product layer.

      2.      These data provides information that helps define adequate groundwater treatment.  Without these data, incorrect (and sometimes unnecessarily expensive) remediation techniques may be designed for a situation where they are not required.

      3.      There are some substantial logistical problems involved with sending a sampler through free product to sample the groundwater below.  Although there are some products designed specifically for this type of sampling, they are expensive and the results may not be commensurate with their cost.  The use of "self-engineered" equipment or coverings may be the best option.

      4.      These data are only to be used for qualitative use and will aid in deciding on an appropriate remediation technique. 

      5.      Wrapping bailers and tubing in plastic seems to be the most popular technique in getting past the product layer.

      6.      Though not recommended, some have wrapped submersible pumps in several layers of plastic and retrieved each layer by a separate lanyard.

      7.      One suggestion would be to use a rigid piece of stainless steel tubing wrapped in plastic.

a.            Once the covered tubing is past the layer, pull up on the plastic, piercing the plastic and exposing the (somewhat) clean tubing inlet.

b.            Introduction of the wrapped hose must be done slowly so as to not entrain any more product into the dissolved layer located below.

c.            Also, this must be done with a peristaltic pump or a vacuum pump linked to a trap bottle.  To use this setup, the water table must be no deeper than 15-20 feet, realizing that actual sampling may be occurring several feet below the product layer.

g.            Sampling Dissolved Metals

      1.      In order to collect a "representative" sample for the purpose of monitoring compliance with groundwater standards for metals, it may be necessary to field filter a sample prior to preservation.

      2.      In situations where the static level in the well allows use of a peristaltic pump, the groundwater sample shall be pumped directly from the well through an in-line filter.

a.            A disposable, high capacity, .45 um filter is an acceptable filter for most applications.  See Fig. 4.2 and Table 4.1 for allowable equipment setups.

b.            In field use, the filter must first be flushed with 30 - 50 mls of deionized water or an inert gas to remove atmospheric oxygen.

c.            The filter must be inserted on the high pressure side (i.e. on the delivery side) of the peristaltic pump.  VACUUM FILTRATION IS NOT ACCEPTABLE.

d.            The sample delivery tube must be long enough (greater than 2 feet) such that back-diffusion of oxygen to the filter is negligible.

e.            New or precleaned silastic tubing shall be installed in the pump at each monitor well.

      3.      In situations where the static water level in the well is too deep for a peristaltic pump to be used directly, there are several alternatives:

a.            Groundwater may be sampled with an appropriately constructed bailer.  The intake tube of the peristaltic pump is inserted into the full bailer and water pumped through a filter as described above.

b.            Any submersible pump of appropriate construction for which the flow rate can be adjusted may be used for water levels below 20'-25'. 

c.            Pressurized HDPE and Teflon bailers may also be used.

d.            See the specific section concerning field filtration in Table 4.1 for all acceptable alternatives.

      4.      It is important that this operation is carried out as rapidly as possible and in such a way that sample agitation and exposure to atmospheric oxygen is minimized.  It is for this reason that pouring the sample into any intermediate vessel for subsequent filtration IS NOT allowed.  This includes barrel or syringe filters.  Once the sample is collected into a sample container, preservation and pH checks should be completed.

4.2.6     Wells with In-Place Plumbing

      Wells with in-place plumbing are generally encountered at wellfields, industrial facilities and private residences.  See separate discussions below on sampling potable water wells.

      4.2.6.1      Purging

a.            The volume to be purged depends on several factors: the depth and diameter of the well, whether the pumps are running continuously or intermittently, how close to the source the sample can be collected, and the presence of any storage/pressure tanks between the sampling point and the pump.

b.            If storage/pressure tanks are present, an adequate volume must be purged to totally exchange the volume of water in the tank (EPA, 1986).

c.            Continuously Running Pumps

      1.      If the pump runs continuously and the sample can be collected prior to a storage/pressure tank, no purging is required, other than opening a valve and allowing it to flush at maximum velocity for at least 15 minutes.

      2.      If the pump runs continuously, and a storage/pressure tank is located ahead of the sample location, the purge must include the entire storage volume to ensure that a sample representative of the groundwater will be collected.

d.            Intermittently Running Pumps

      1.      If the pump runs intermittently it is necessary to determine the volume to be purged, including storage pressure tanks that are located ahead of the sampling location.

      2.      The pump should then run continuously until the required volume has been purged.

      3.      When the well depth or diameter is unknown (as is frequently the case with in-place plumbing) purging should be carried out by pumping the well for 15 minutes and until the pH, specific conductance and temperature stabilize.

a.            In practice, stable sample chemistry is indicated when the purging parameter values remain within 5% over two successive samples taken at least 5 minutes apart.

      4.2.6.2      Sampling

            All samples must be collected from the closest spigot to the well head, with all screens or aerators removed, and with the flow rate reduced to no more than 500 ml/min.

4.2.7            Potable Well Sampling

      The following procedures describe generalized drinking water sampling from private potable wells.  If the samples are collected for compliance with the drinking water regulations (Chapters 17-524, 17-550 or 17-555, F.A.C.), the samples must be analyzed by a laboratory with Drinking Water Certification.  If the samples are being analyzed in response to other programs (contamination assessment, consent order, etc.), the laboratory shall meet the requirements of the specified Category.

      4.2.7.1      General Concerns

a.      Appropriate containers and preservatives must be selected prior to sampling.

      1.         Containers and preservatives shall comply with Tables 4.2, 4.3, 4.4 and 4.5.

      2.         Containers and preservatives may be obtained from a laboratory with appropriate credentials (see discussion above).

      3.         It is recommended that the laboratory add the appropriate preservative to the container.

b.      The laboratory may include special handling instructions with the sample containers.  These must be read carefully and must comply with the generalized instructions listed below.

      4.2.7.2      Sampling Drinking Water Wells

a.      As a general rule, purging and sample should be from a spigot closest to the well head.

      1.         If possible, the spigot should be before the holding tank and filters.  If this not possible, the contents of the holding tank must also be purged.

      2.         Remove all aerators and filters (if possible).

b.      Depending on the running schedule of the well and the placement of the pressure tank, purge the system as described in Section 4.2.6.1.

c.      If the capacity of the pressure tank is not known, purge for at least 15 - 20 minutes at maximum velocity.

d.      Reduce flow to approximately 500 ml/minute (a 1/8" stream).

e.      Sample Containers with no preservatives:

      1.         Remove the screw cap from the bottle.  Do not touch the interior of the cap or the container with hand or the spigot.

      2.         Fill approximately 1/4 full, rinse the interior of the container and discard the water.

      3.         DO NOT RINSE CONTAINERS IF collecting samples for oil and grease, total recoverable hydrocarbons, volatile organics (including trihalomethanes) or microbiologicals.

      4.         Tilt the container so that flow falls onto the interior surface.  DO NOT AGITATE OR SHAKE CONTAINER WHILE FILLING.

      5.         Fill the bottle to almost to capacity (if collecting VOC or trihalomethane samples, see 4.2.7.2.i below).

      6.         Replace the screw cap securely on the bottle.

f.      Sample containers with preservatives.

      1.         Follow the same protocol outlined above, deleting the rinse.

      2.         Since some of the preservatives may react with the sample water, hold the open end of the container away from you while filling.

      3.         After replacing the cap, gently tip the container several times to mix the preservatives.

g.      Affix a sample label and seal (if required), and complete the chain-of-custody form.

h.      Place the sample bottle in a plastic sample bag and cool to 4 C on wet ice.

i.      Special Sampling Protocols

      The special precautions for the types of samples discussed in Section 4.2.2 shall be followed.

      4.2.7.3      Sampling Drinking Water Sources for Lead and Copper

a.      Selection of the sampling point is dependent on whether the sample is being taken to verify compliance with the Drinking Water Regulations.  If so, the sample must be collected from a COLD WATER tap in either the kitchen or bathroom.

b.      Samples must be collected after the water HAS NOT been used for at least SIX HOURS.

c.      DO NOT FLUSH OR PURGE THE SYSTEM.

d.      Collect the first flush into the sample container for trace metals.  DO NOT RINSE SAMPLE CONTAINER.

e.      Tilt the container so that the initial flow falls onto the interior surface.  DO NOT AGITATE.

f.      If the container was prepreserved, hold the open end of the container away from you while filling.

g.      Add preservatives (if needed).

h.      Replace screw cap and gently tip the container several times to mix the preservatives.

I.      Affix a sample label and seal (if required), and complete the chain-of-custody form.

j.      Place the sample bottle in a plastic sample bag.

4.2.8            Drinking Water Supply System Sampling

      The following protocols shall be followed:

      1.   When sampling for drinking water compliance, the sampling spigot is normally designated by permit or municipal authorities.  The location may be near the supply line or may be an outside spigot on a private residence.

      2.      Procedures to sample drinking water directly from the supply system is the same as above, except for treatment of residual chlorine.

a.            Lines shall be flushed for 2 to 5 minutes before collecting any samples.

b.            Reduce the flow rate to less than 500 ml/min (1/8" stream) before collecting samples.

      3.   In many instances, the water supply to residences maybe treated with chlorine which may cause interference with certain types of analyses (ex: VOC; Semi-Volatiles and some bacteriological samples).  Residual chlorine must be treated with the addition of sodium thiosulfate (Na2S2O3).

      4.   Utilizing chemical kits (such as HACH), test the water in a separate container for residual chlorine.  If residual chlorine is present, collect the sample in the appropriate sample container(s) using the required preservatives.

a.            Immediately upon sample collection add 0.008% Na2S2O3 or 100 mg of Na2S2O3 per 1 liter of sample water directly into the sample container.

b.            After replacing the cap, tip the container several times to mix the preservative.

      5.   Affix a sample label, seal and transport on wet ice.

      6.   Lead and copper shall be sampled according to protocols outlined in 4.2.7.3.

4.2.9            Temporary Well Points

      Temporary well points include those drilled with augers as well as those pushed with "direct push" or DPT devices.  These types of wells are not permanently installed.

      4.2.9.1      Use

a.            Temporary well points may be used for PRELIMINARY INVESTIGATIONS and as a SCREENING TOOL.

[[b.                   For formal site work (not preliminary or PCAP), temporary well points may only be allowed under emergency situations.  These are:

            1.            DOT right-of-ways,

            2.            private property where a permanent well cannot be placed, or

            3.            inside or up against a structure.]]

c.            DER will determine whether temporary well points are warranted.

d.            If these wells are used to provide formal data, these restrictions apply:

            1.            Use precleaned equipment as described in Table 4.1;

            2.            Well must be purged of 3-5 well volumes (or dry);

            3.            Sampling with a peristaltic pump

a.            Extractable organics shall be collected via an all-Teflon and -glass organic trap configuration (see Figure 2.1);

b.            VOCs shall not be collected through a pump, but the Teflon pump tubing is allowed to fill via ambient pressure, capped with stopper or gloved finger, carefully withdrawn from the well, and drained into appropriate vials.

c.            Refer to protocols listed in 4.2.5.5 and 4.2.5.6 for specific information on sampling and configuration.

            4.            Sampling with bailers

a.            In some cases, sampling may be accomplished with a 3/4" bailer.

b.            All equipment construction restrictions shall be followed.

c.            Refer to bailer sampling protocols in section 4.2.6.5.

4.2.10  Airstripper and Remedial Treatment System Sampling

a.            Collect effluent samples from airstripper units in a similar manner to those described for Drinking Water Supply Systems (Section 4.2.8).

b.            Remove any tubing from the sampling port and flush for one to two minutes.

c.            Reduce flow rate to less than 500 ml/min. and begin sample collection.

4.2.11            Bioassay Sampling

      When collecting samples for bioassays, the sampling protocols outlined in Section 4.2.3 (Surface Water) and 4.2.4 (Wastewater) shall be followed.

      The holding time for bioassay samples is 72 hours.