APPENDIX A TO PART 136

METHODS FOR ORGANIC CHEMICAL ANALYSIS OF MUNICIPAL AND

INDUSTRIAL WASTEWATER

METHOD 608—ORGANOCHLORINE PESTICIDES AND PCBS

1. Scope and Application

1.1 This method covers the determination of certain organochlorine pesticides and PCBs.

The following parameters can be determined by this method:

Parameter STORET No. CAS No.

Aldrin ........................ "-BHC ........................ $-BHC ........................ *-BHC ........................ (-BHC ........................

Chlordane .....................

4,4'-DDD ......................

4,4'-DDE ......................

4,4'-DDT ......................

Dieldrin .......................

Endosulfan I ...................

Endosulfan II ..................

Endosulfan sulfate ...............

Endrin ........................

Endrin aldehyde ................

Heptachlor ....................

Heptachlor epoxide ..............

Toxaphene .....................

PCB-1016. .....................

PCB-1221 ......................

PCB-1232 ......................

PCB-1242 ......................

PCB-1248 ......................

PCB-1254 ......................

PCB-1260 ......................

39330 309-00-2

39337 319-84-6

39338 319-85-7

34259 319-86-8

39340 58-89-9

39350 57-74-9

39310 72-54-8

39320 72-55-9

39300 50-29-3

39380 60-57-1

34361 959-98-8

34356 33212-65-9

34351 1031-07-8

39390 72-20-8

34366 7421-93-4

39410 76-44-8

39420 1024-57-3

39400 8001-35-2

34671 12674-11-2

39488 1104-28-2

39492 11141-16-5

39496 53469-21-9

39500 12672-29-6

39504 11097-69-1

39508 11096-82-5

1.2 This is a gas chromatographic (GC) method applicable to the determination of the

compounds listed above in municipal and industrial discharges as provided under

40 CFR Part 136.1. When this method is used to analyze unfamiliar samples for any or

all of the compounds above, compound identifications should be supported by at least

one additional qualitative technique. This method describes analytical conditions for a

second gas chromatographic column that can be used to confirm measurements made

with the primary column. Method 625 provides gas chromatograph/mass spectrometer

(GC/MS) conditions appropriate for the qualitative and quantitative confirmation of

results for all of the parameters listed above, using the extract produced by this method.
1.3 The method detection limit (MDL, defined in Section 14.1) for each parameter is listed 1

in Table 1. The MDL for a specific wastewater may differ from those listed, depending

upon the nature of interferences in the sample matrix.

1.4 The sample extraction and concentration steps in this method are essentially the same as

in Methods 606, 609, 611, and 612. Thus, a single sample may be extracted to measure

the parameters included in the scope of each of these methods. When cleanup is

required, the concentration levels must be high enough to permit selecting aliquots, as

necessary, to apply appropriate cleanup procedures. The analyst is allowed the latitude,

under Section 12, to select chromatographic conditions appropriate for the simultaneous

measurement of combinations of these parameters.

1.5 Any modification of this method, beyond those expressly permitted, shall be considered

as a major modification subject to application and approval of alternate test procedures

under 40 CFR Parts 136.4 and 136.5.

1.6 This method is restricted to use by or under the supervision of analysts experienced in

the use of a gas chromatograph and in the interpretation of gas chromatograms. Each

analyst must demonstrate the ability to generate acceptable results with this method

using the procedure described in Section 8.2.

2. Summary of Method

2.1 A measured volume of sample, approximately 1 L, is extracted with methylene chloride

using a separatory funnel. The methylene chloride extract is dried and exchanged to

hexane during concentration to a volume of 10 mL or less. The extract is separated by

gas chromatography and the parameters are then measured with an electron capture

detector.2

2.2 The method provides a Florisil column cleanup procedure and an elemental sulfur

removal procedure to aid in the elimination of interferences that may be encountered.

3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware,

and other sample processing hardware that lead to discrete artifacts and/or elevated

baselines in gas chromatograms. All of these materials must be routinely demonstrated

to be free from interferences under the conditions of the analysis by running laboratory

reagent blanks as described in Section 8.1.3.

3.1.1 Glassware must be scrupulously cleaned. Clean all glassware as soon as possible 3

after use by rinsing with the last solvent used in it. Solvent rinsing should be

followed by detergent washing with hot water, and rinses with tap water and

distilled water. The glassware should then be drained dry, and heated in a

muffle furnace at 400°C for 15-30 minutes. Some thermally stable materials, such

as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone

and pesticide quality hexane may be substituted for the muffle furnace heating.

Thorough rinsing with such solvents usually eliminates PCB interference.

Volumetric ware should not be heated in a muffle furnace. After drying and

cooling, glassware should be sealed and stored in a clean environment to prevent
any accumulation of dust or other contaminants. Store inverted or capped with

aluminum foil.

3.1.2 The use of high purity reagents and solvents helps to minimize interference

problems. Purification of solvents by distillation in all-glass systems may be

required.

3.2 Interferences by phthalate esters can pose a major problem in pesticide analysis when

using the electron capture detector. These compounds generally appear in the

chromatogram as large late eluting peaks, especially in the 15 and 50% fractions from

Florisil. Common flexible plastics contain varying amounts of phthalates. These

phthalates are easily extracted or leached from such materials during laboratory

operations. Cross contamination of clean glassware routinely occurs when plastics are

handled during extraction steps, especially when solvent-wetted surfaces are handled.

Interferences from phthalates can best be minimized by avoiding the use of plastics in

the laboratory. Exhaustive cleanup of reagents and glassware may be required to

eliminate background phthalate contamination. T interferences from phthalate esters 4,5

can be avoided by using a microcoulometric or electrolytic conductivity detector.

3.3 Matrix interferences may be caused by contaminants that are co-extracted from the

sample. The extent of matrix interferences will vary considerably from source to source,

depending upon the nature and diversity of the industrial complex or municipality being

sampled. The cleanup procedures in Section 11 can be used to overcome many of these

interferences, but unique samples may require additional cleanup approaches to achieve

the MDL listed in Table 1.

4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely

defined; however, each chemical compound should be treated as a potential health

hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest

possible level by whatever means available. The laboratory is responsible for maintaining

a current awareness file of OSHA regulations regarding the safe handling of the

chemicals specified in this method. A reference file of material data handling sheets

should also be made available to all personnel involved in the chemical analysis.

Additional references to laboratory safety are available and have been identified for the 6-8

information of the analyst.

4.2 The following parameters covered by this method have been tentatively classified as

known or suspected, human or mammalian carcinogens: 4,4′-DDT, 4,4′-DDD, the BHCs,

and the PCBs. Primary standards of these toxic compounds should be prepared in a

hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst

handles high concentrations of these toxic compounds.
5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.

5.1.1 Grab sample bottle— 1-L or 1-qt, amber glass, fitted with a screw cap lined with

Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber

bottles are not available, protect samples from light. The bottle and cap liner

must be washed, rinsed with acetone or methylene chloride, and dried before use

to minimize contamination.

5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample

containers for the collection of a minimum of 250 mL of sample. Sample

containers must be kept refrigerated at 4°C and protected from light during

compositing. If the sampler uses a peristaltic pump, a minimum length of

compressible silicone rubber tubing may be used. Before use, however, the

compressible tubing should be thoroughly rinsed with methanol, followed by

repeated rinsings with distilled water to minimize the potential for contamination

of the sample. An integrating flow meter is required to collect flow proportional

composites.

5.2. Glassware (All specifications are suggested. Catalog numbers are included for illustration

only.)

5.2.1 Separatory funnel— 2-L, with Teflon stopcock.

5.2.2 Drying column—Chromatographic column, approximately 400 mm long x 19 mm

ID, with coarse frit filter disc.

5.2.3 Chromatographic column—400 mm long x 22 mm ID, with Teflon stopcock and

coarse frit filter disc (Kontes K-42054 or equivalent).

5.2.4 Concentrator tube, Kuderna-Danish— 10-mL, graduated (Kontes K-570050-1025

or equivalent). Calibration must be checked at the volumes employed in the test.

Ground glass stopper is used to prevent evaporation of extracts.

5.2.5 Evaporative flask, Kuderna-Danish—500- mL (Kontes K-570001-0500 or

equivalent). Attach to concentrator tube with springs.

5.2.6 Snyder column, Kuderna/Danish—Three-ball macro (Kontes K-503000-0121 or

equivalent).

5.2.7 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.

5.3 Boiling chips-Approximately 10/40 mesh. Heat to 400°C for 30 minutes or Soxhlet

extract with methylene chloride.

5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2°C).

The bath should be used in a hood.

5.5 Balance—Analytical, capable of accurately weighing 0.0001 g.
5.6 Gas chromatograph—An analytical system complete with gas chromatograph suitable for

on-column injection and all required accessories including syringes, analytical columns,

gases, detector, and strip-chart recorder. A data system is recommended for measuring

peak areas.

5.6.1 Column 1—1.8 m long x 4 mm ID glass, packed with 1.5% SP-2250/1.95%

SP-2401 on Supelcoport (100/120 mesh) or equivalent. This column was used to

develop the method performance statements in Section 14. Guidelines for the use

of alternate column packings are provided in Section 12.1.

5.6.2 Column 2—1.8 m long x 4 mm ID glass, packed with 3% OV-1 on Supelcoport

(100/120 mesh) or equivalent.

5.6.3 Detector—Electron capture detector. This detector has proven effective in the

analysis of wastewaters for the parameters listed in the scope (Section 1.1), and

was used to develop the method performance statements in Section 14.

Guidelines for the use of alternate detectors are provided in Section 12.1.

6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not

observed at the MDL of the parameters of interest.

6.2 Sodium hydroxide solution (10 N)—Dissolve 40 g of NaOH (ACS) in reagent water and

dilute to 100 mL.

6.3 Sodium thiosulfate—(ACS) Granular.

6.4 Sulfuric acid (1+1)—Slowly, add 50 mL to H SO (ACS, sp. gr. 1.84) to 50 mL of reagent 2 4

water.

6.5 Acetone, hexane, isooctane, methylene chloride—Pesticide quality or equivalent.

6.6 Ethyl ether—Nanograde, redistilled in glass if necessary.

6.6.1 Ethyl ether must be shown to be free of peroxides before it is used as indicated

by EM Laboratories Quant test strips. (Available from Scientific Products Co.,

Cat. No. P1126-8, and other suppliers.)

6.6.2 Procedures recommended for removal of peroxides are provided with the test

strips. After cleanup, 20 mL of ethyl alcohol preservative must be added to each

liter of ether.

6.7 Sodium sulfate—(ACS) Granular, anhydrous. Purify by heating at 400°C for four hours

in a shallow tray.

6.8 Florisil—-PR grade (60/100 mesh). Purchase activated at 1250°F and store in the dark

in glass containers with ground glass stoppers or foil-lined screw caps. Before use,

activate each batch at least 16 hours at 130°C in a foil-covered glass container and allow

to cool.
6.9 Mercury—Triple distilled.

6.10 Copper powder—Activated.

6.11 Stock standard solutions (1.00 μg/μL)—Stock standard solutions can be prepared from

pure standard materials or purchased as certified solutions.

6.11.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure

material. Dissolve the material in isooctane and dilute to volume in a 10 mL

volumetric flask. Larger volumes can be used at the convenience of the analyst.

When compound purity is assayed to be 96% or greater, the weight can be used

without correction to calculate the concentration of the stock standard.

Commercially prepared stock standards can be used at any concentration if they

are certified by the manufacturer or by an independent source.

6.11.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store

at 4°C and protect from light. Stock standard solutions should be checked

frequently for signs of degradation or evaporation, especially just prior to

preparing calibration standards from them.

6.11.3 Stock standard solutions must be replaced after six months, or sooner if

comparison with check standards indicates a problem.

6.12 Quality control check sample concentrate—See Section 8.2.1.

7. Calibration

7.1 Establish gas chromatographic operating conditions equivalent to those given in Table 1.

The gas chromatographic system can be calibrated using the external standard technique

(Section 7.2) or the internal standard technique (Section 7.3).

7.2 External standard calibration procedure

7.2.1 Prepare calibration standards at a minimum of three concentration levels for each

parameter of interest by adding volumes of one or more stock standards to a

volumetric flask and diluting to volume with isooctane. One of the external

standards should be at a concentration near, but above, the MDL (Table 1) and

the other concentrations should correspond to the expected range of

concentrations found in real samples or should define the working range of the

detector.

7.2.2 Using injections of 2-5 μL, analyze each calibration standard according to Section

12 and tabulate peak height or area responses against the mass injected. The

results can be used to prepare a calibration curve for each compound.

Alternatively, if the ratio of response to amount injected (calibration factor) is a

constant over the working range (<10% relative standard deviation, RSD),

linearity through the origin can be assumed and the average ratio or calibration

factor can be used in place of a calibration curve.
This equation corrects an error made in the original method publication (49 FR 43234, *

October 26, 1984). This correction will be formalized through a rulemaking in FY97.

7.3 Internal standard calibration procedure—To use this approach, the analyst must select

one or more internal standards that are similar in analytical behavior to the compounds

of interest. The analyst must further demonstrate that the measurement of the internal

standard is not affected by method or matrix interferences. Because of these limitations,

no internal standard can be suggested that is applicable to all samples.

7.3.1 Prepare calibration standards at a minimum of three concentration levels for each

parameter of interest by adding volumes of one or more stock standards to a

volumetric flask. To each calibration standard, add a known constant amount of

one or more internal standards, and dilute to volume with isooctane. One of the

standards should be at a concentration near, but above, the MDL and the other

concentrations should correspond to the expected range of concentrations found

in real samples or should define the working range of the detector.

7.3.2 Using injections of 2-5 μL, analyze each calibration standard according to Section

12 and tabulate peak height or area responses against concentration for each

compound and internal standard. Calculate response factors (RF) for each

compound using Equation 1.

Equation 1

where:

A = Response for the parameter to be measured. s

A = Response for the internal standard. is

C = Concentration of the internal standard (μg/L). is

C = Concentration of the parameter to be measured (μg/L). s

If the RF value over the working range is a constant (<10% RSD), the RF can be

assumed to be invariant and the average RF can be used for calculations.

Alternatively, the results can be used to plot a calibration curve of response ratios,

A /A , vs. concentration ratios C /C . s is s is

*

7.4 The working calibration curve, calibration factor, or RF must be verified on each working

day by the measurement of one or more calibration standards. If the response for any

parameter varies from the predicted response by more than ±15%, the test must be

repeated using a fresh calibration standard. Alternatively, a new calibration curve must

be prepared for that compound.

7.5 The cleanup procedure in Section 11 utilizes Florisil column chromatography. Florisil

from different batches or sources may vary in adsorptive capacity. To standardize the

amount of Florisil which is used, the use of lauric acid value is suggested. The 9
referenced procedure determines the adsorption from hexane solution of lauric acid (mg)

per g of Florisil. The amount of Florisil to be used for each column is calculated by

dividing 110 by this ratio and multiplying by 20 g.

7.6 Before using any cleanup procedure, the analyst must process a series of calibration

standards through the procedure to validate elution patterns and the absence of

interferences from the reagents.

8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control

program. The minimum requirements of this program consist of an initial demonstration

of laboratory capability and an ongoing analysis of spiked samples to evaluate and

document data quality. The laboratory must maintain records to document the quality

of data that is generated. Ongoing data quality checks are compared with established

performance criteria to determine if the results of analyses meet the performance

characteristics of the method. When results of sample spikes indicate atypical method

performance, a quality control check standard must be analyzed to confirm that the

measurements were performed in an in-control mode of operation.

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to

generate acceptable accuracy and precision with this method. This ability is

established as described in Section 8.2.

8.1.2 In recognition of advances that are occurring in chromatography, the analyst is

permitted certain options (detailed in Sections 10.4, 11.1, and 12.1) to improve the

separations or lower the cost of measurements. Each time such a modification is

made to the method, the analyst is required to repeat the procedure in Section 8.2.

8.1.3 Before processing any samples, the analyst must analyze a reagent water blank

to demonstrate that interferences from the analytical system and glassware are

under control. Each time a set of samples is extracted or reagents are changed,

a reagent water blank must be processed as a safeguard against laboratory

contamination.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10%

of all samples to monitor and evaluate laboratory data quality. This procedure

is described in Section 8.3.

8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of

quality control check standards that the operation of the measurement system is

in control. This procedure is described in Section 8.4. The frequency of the check

standard analyses is equivalent to 10% of all samples analyzed but may be

reduced if spike recoveries from samples (Section 8.3) meet all specified quality

control criteria.

8.1.6 The laboratory must maintain performance records to document the quality of

data that is generated. This procedure is described in Section 8.5.
8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must

perform the following operations.

8.2.1 A quality control (QC) check sample concentrate is required containing each

single-component parameter of interest at the following concentrations in acetone:

4,4′SDDD, 10 μg/mL; 4,4′SDDT, 10 μg/mL; endosulfan II, 10 μg/mL; endosulfan

sulfate, 10 μg/mL; endrin, 10 μg/mL; any other single-component pesticide, 2

μg/mL. If this method is only to be used to analyze for PCBs, chlordane, or

toxaphene, the QC check sample concentrate should contain the most

representative multicomponent parameter at a concentration of 50 μg/mL in

acetone. The QC check sample concentrate must be obtained from the U.S.

Environmental Protection Agency, Environmental Monitoring and Support

Laboratory in Cincinnati, Ohio, if available. If not available from that source, the

QC check sample concentrate must be obtained from another external source. If

not available from either source above, the QC check sample concentrate must be

prepared by the laboratory using stock standards prepared independently from

those used for calibration.

8.2.2 Using a pipet, prepare QC check samples at the test concentrations shown in

Table 3 by adding 1.00 mL of QC check sample concentrate to each of four 1-L

aliquots of reagent water.

8.2.3 Analyze the well-mixed QC check samples according to the method beginning in

Section 10.

8.2.4 Calculate the average recovery ( ) in μg/mL; and the standard deviation of the

recovery (s) in μg/mL, for each parameter using the four results.

8.2.5 For each parameter compare s and with the corresponding acceptance criteria

for precision and accuracy, respectively, found in Table 3. If s and for all

parameters of interest meet the acceptance criteria, the system performance is

acceptable and analysis of actual samples can begin. If any individual s exceeds

the precision limit or any individual falls outside the range for accuracy, the

system performance is unacceptable for that parameter.

NOTE: The large number of parameters in Table 3 present a substantial

probability that one or more will fail at least one of the acceptance

criteria when all parameters are analyzed.

8.2.6 When one or more of the parameters tested fail at least one of the acceptance

criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.

8.2.6.1 Locate and correct the source of the problem and repeat the test for all

parameters of interest beginning with Section 8.2.2.
8.2.6.2 Beginning with Section 8.2.2, repeat the test only for those parameters that

failed to meet criteria. Repeated failure, however, will confirm a general

problem with the measurement system. If this occurs, locate and correct

the source of the problem and repeat the test for all compounds of interest

beginning with Section 8.2.2.

8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each

sample site being monitored to assess accuracy. For laboratories analyzing one to ten

samples per month, at least one spiked sample per month is required.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter

in the sample is being checked against a regulatory concentration limit, the

spike should be at that limit or one to five times higher than the

background concentration determined in Section 8.3.2, whichever

concentration would be larger.

8.3.1.2 If the concentration of a specific parameter in the sample is not being

checked against a limit specific to that parameter, the spike should be at

the test concentration in Section 8.2.2 or one to five times higher than the

background concentration determined in Section 8.3.2, whichever

concentration would be larger.

8.3.1.3 If it is impractical to determine background levels before spiking (e.g.,

maximum holding times will be exceeded), the spike concentration should

be (1) the regulatory concentration limit, if any; or, if none (2) the larger

of either five times higher than the expected background concentration or

the test concentration in Section 8.2.2.

8.3.2 Analyze one sample aliquot to determine the background concentration (B) of

each parameter. If necessary, prepare a new QC check sample concentrate

(Section 8.2.1) appropriate for the background concentrations in the sample. Spike

a second sample aliquot with 1.0 mL of the QC check sample concentrate and

analyze it to determine the concentration after spiking (A) of each parameter.

Calculate each percent recovery (P) as 100 (A-B)%/T, where T is the known true

value of the spike.

8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC

acceptance criteria found in Table 3. These acceptance criteria were calculated to

include an allowance for error in measurement of both the background and spike

concentrations, assuming a spike to background ratio of 5:1. This error will be

accounted for to the extent that the analyst's spike to background ratio

approaches 5:1. If spiking was performed at a concentration lower than the test 10

concentration in Section 8.2.2, the analyst must use either the QC acceptance

criteria in Table 3, or optional QC acceptance criteria calculated for the specific

spike concentration. To calculate optional acceptance criteria for the recovery of

a parameter: (1) Calculate accuracy (X') using the equation in Table 4,

substituting the spike concentration (T) for C; (2) calculate overall precision (S')
using the equation in Table 4, substituting X' for ; (3) calculate the range for

recovery at the spike concentration as (100 X'/T) ±2.44(100 S'/T)%.10

8.3.4 If any individual P falls outside the designated range for recovery, that parameter

has failed the acceptance criteria. A check standard containing each parameter

that failed the criteria must be analyzed as described in Section 8.4.

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check

standard containing each parameter that failed must be prepared and analyzed.

NOTE: The frequency for the required analysis of a QC check standard will

depend upon the number of parameters being simultaneously tested, the

complexity of the sample matrix, and the performance of the laboratory.

If the entire list of parameters in Table 3 must be measured in the sample

in Section 8.3, the probability that the analysis of a QC check standard will

be required is high. In this case the QC check standard should be

routinely analyzed with the spike sample.

8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate

(Section 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only

to contain the parameters that failed criteria in the test in Section 8.3.

8.4.2 Analyze the QC check standards to determine the concentration measured (A) of

each parameter. Calculate each percent recovery (P ) as 100 (A/T)%, where T is s

the true value of the standard concentration.

8.4.3 Compare the percent recovery (P ) for each parameter with the corresponding QC s

acceptance criteria found in Table 3. Only parameters that failed the test in

Section 8.3 need to be compared with these criteria. If the recovery of any such

parameter falls outside the designated range, the laboratory performance for that

parameter is judged to be out of control, and the problem must be immediately

identified and corrected. The analytical result for that parameter in the unspiked

sample is suspect and may not be reported for regulatory compliance purposes.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples

must be assessed and records must be maintained. After the analysis of five spiked

wastewater samples as in Section 8.3, calculate the average percent recovery ( ) and the

standard deviation of the percent recovery (s ). Express the accuracy assessment as a p

percent recovery interval from -2 s to +2 s . If =90% and s =10%, for example, the pp p

accuracy interval is expressed as 70-110%. Update the accuracy assessment for each

parameter on a regular basis (e.g., after each 5-10 new accuracy measurements).

8.6 It is recommended that the laboratory adopt additional quality assurance practices for

use with this method. The specific practices that are most productive depend upon the

needs of the laboratory and the nature of the samples. Field duplicates may be analyzed

to assess the precision of the environmental measurements. When doubt exists over the

identification of a peak on the chromatogram, confirmatory techniques such as gas

chromatography with a dissimilar column, specific element detector, or mass

spectrometer must be used. Whenever possible, the laboratory should analyze standard

reference materials and participate in relevant performance evaluation studies.
9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices11

should be followed, except that the bottle must not be prerinsed with sample before

collection. Composite samples should be collected in refrigerated glass containers in

accordance with the requirements of the program. Automatic sampling equipment must

be as free as possible of Tygon tubing and other potential sources of contamination.

9.2 All samples must be iced or refrigerated at 4°C from the time of collection until

extraction. If the samples will not be extracted within 72 hours of collection, the sample

should be adjusted to a pH range of 5.0-9.0 with sodium hydroxide solution or sulfuric

acid. Record the volume of acid or base used. If aldrin is to be determined, add sodium

thiosulfate when residual chlorine is present. EPA Methods 330.4 and 330.5 may be used

for measurement of residual chlorine. Field test kits are available for this purpose. 12

9.3 All samples must be extracted within seven days of collection and completely analyzed

within 40 days of extraction.2

10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of

sample volume. Pour the entire sample into a 2 L separatory funnel.

10.2 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 seconds to

rinse the inner surface. Transfer the solvent to the separatory funnel and extract the

sample by shaking the funnel for two minutes with periodic venting to release excess

pressure. Allow the organic layer to separate from the water phase for a minimum of

10 minutes. If the emulsion interface between layers is more than one-third the volume

of the solvent layer, the analyst must employ mechanical techniques to complete the

phase separation. The optimum technique depends upon the sample, but may include

stirring, filtration of the emulsion through glass wool, centrifugation, or other physical

methods. Collect the methylene chloride extract in a 250 mL Erlenmeyer flask.

10.3 Add a second 60 mL volume of methylene chloride to the sample bottle and repeat the

extraction procedure a second time, combining the extracts in the Erlenmeyer flask.

Perform a third extraction in the same manner.

10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10 mL concentrator tube

to a 500 mL evaporative flask. Other concentration devices or techniques may be used

in place of the K-D concentrator if the requirements of Section 8.2 are met.

10.5 Pour the combined extract through a solvent-rinsed drying column containing about

10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator.

Rinse the Erlenmeyer flask and column with 20-30 mL of methylene chloride to complete

the quantitative transfer.

10.6 Add one or two clean boiling chips to the evaporative flask and attach a three-ball

Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride

to the top. Place the K-D apparatus on a hot water bath (60-65°C) so that the

concentrator tube is partially immersed in the hot water, and the entire lower rounded
surface of the flask is bathed with hot vapor. Adjust the vertical position of the

apparatus and the water temperature as required to complete the concentration in 15-20

minutes. At the proper rate of distillation the balls of the column will actively chatter

but the chambers will not flood with condensed solvent. When the apparent volume of

liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least

10 minutes.

10.7 Increase the temperature of the hot water bath to about 80°C. Momentarily remove the

Snyder column, add 50 mL of hexane and a new boiling chip, and reattach the Snyder

column. Concentrate the extract as in Section 10.6, except use hexane to prewet the

column. The elapsed time of concentration should be 5-10 minutes.

10.8 Remove the Snyder column and rinse the flask and its lower joint into the concentrator

tube with 1-2 mL of hexane. A 5 mL syringe is recommended for this operation.

Stopper the concentrator tube and store refrigerated if further processing will not be

performed immediately. If the extract will be stored longer than two days, it should be

transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further

cleanup, proceed with gas chromatographic analysis (Section 12). If the sample requires

further cleanup, proceed to Section 11.

10.9 Determine the original sample volume by refilling the sample bottle to the mark and

transferring the liquid to a 1000 mL graduated cylinder. Record the sample volume to

the nearest 5 mL.

11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If

particular circumstances demand the use of a cleanup procedure, the analyst may use

either procedure below or any other appropriate procedure. However, the analyst first

must demonstrate that the requirements of Section 8.2 can be met using the method as

revised to incorporate the cleanup procedure. The Florisil column allows for a select

fractionation of the compounds and will eliminate polar interferences. Elemental sulfur,

which interferes with the electron capture gas chromatography of certain pesticides, can

be removed by the technique described in Section 11.3.

11.2 Florisil column cleanup

11.2.1 Place a weight of Florisil (nominally 20 g) predetermined by calibration

(Section 7.5), into a chromatographic column. Tap the column to settle the Florisil

and add 1-2 cm of anhydrous sodium sulfate to the top.

11.2.2 Add 60 mL of hexane to wet and rinse the sodium sulfate and Florisil. Just prior

to exposure of the sodium sulfate layer to the air, stop the elution of the hexane

by closing the stopcock on the chromatographic column. Discard the eluate.

11.2.3 Adjust the sample extract volume to 10 mL with hexane and transfer it from the

K-D concentrator tube onto the column. Rinse the tube twice with 1-2 mL of

hexane, adding each rinse to the column.
11.2.4 Place a 500 mL K-D flask and clean concentrator tube under the chromatographic

column. Drain the column into the flask until the sodium sulfate layer is nearly

exposed. Elute the column with 200 mL of 6% ethyl ether in hexane (V/V)

(Fraction 1) at a rate of about 5 mL/min. Remove the K-D flask and set it aside

for later concentration. Elute the column again, using 200 mL of 15% ethyl ether

in hexane (V/V) (Fraction 2), into a second K-D flask. Perform the third elution

using 200 mL of 50% ethyl ether in hexane (V/V) (Fraction 3). The elution

patterns for the pesticides and PCBs are shown in Table 2.

11.2.5 Concentrate the fractions as in Section 10.6, except use hexane to prewet the

column and set the water bath at about 85°C. When the apparatus is cool,

remove the Snyder column and rinse the flask and its lower joint into the

concentrator tube with hexane. Adjust the volume of each fraction to 10 mL with

hexane and analyze by gas chromatography (Section 12).

11.3 Elemental sulfur will usually elute entirely in Fraction 1 of the Florisil column cleanup.

To remove sulfur interference from this fraction or the original extract, pipet 1.00 mL of

the concentrated extract into a clean concentrator tube or Teflon-sealed vial. Add one to

three drops of mercury and seal. Agitate the contents of the vial for 15-30 seconds. 13

Prolonged shaking (two hours) may be required. If so, this may be accomplished with

a reciprocal shaker. Alternatively, activated copper powder may be used for sulfur

removal. Analyze by gas chromatography. 14

12. Gas Chromatography

12.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph.

Included in this table are retention times and MDL that can be achieved under these

conditions. Examples of the separations achieved by Column 1 are shown in Figures 1

to 10. Other packed or capillary (open-tubular) columns, chromatographic conditions,

or detectors may be used if the requirements of Section 8.2 are met.

12.2 Calibrate the system daily as described in Section 7.

12.3 If the internal standard calibration procedure is being used, the internal standard must

be added to the sample extract and mixed thoroughly immediately before injection into

the gas chromatograph.

12.4 Inject 2-5 μL of the sample extract or standard into the gas chromatograph using the

solvent-flush technique. Smaller (1.0 μL) volumes may be injected if automatic devices 15

are employed. Record the volume injected to the nearest 0.05 μL, the total extract

volume, and the resulting peak size in area or peak height units.

12.5 Identify the parameters in the sample by comparing the retention times of the peaks in

the sample chromatogram with those of the peaks in standard chromatograms. The

width of the retention time window used to make identifications should be based upon

measurements of actual retention time variations of standards over the course of a day.

Three times the standard deviation of a retention time for a compound can be used to

calculate a suggested window size; however, the experience of the analyst should weigh

heavily in the interpretation of chromatograms.
12.6 If the response for a peak exceeds the working range of the system, dilute the extract and

reanalyze.

12.7 If the measurement of the peak response is prevented by the presence of interferences,

further cleanup is required.

13. Calculations

13.1 Determine the concentration of individual compounds in the sample.

13.1.1 If the external standard calibration procedure is used, calculate the amount of

material injected from the peak response using the calibration curve or calibration

factor determined in Section 7.2.2. The concentration in the sample can be

calculated from Equation 2.

Equation 2

where:

A = Amount of material injected (ng).

V = Volume of extract injected (μL). i

V = Volume of total extract (μL). t

V = Volume of water extracted (mL). s

13.1.2 If the internal standard calibration procedure is used, calculate the concentration

in the sample using the response factor (RF) determined in Section 7.3.2 and

Equation 3.
Equation 3

where:

A = Response for the parameter to be measured. s

A = Response for the internal standard. is

I = Amount of internal standard added to each extract (μg). s

V = Volume of water extracted (L). o

13.2 When it is apparent that two or more PCB (Aroclor) mixtures are present, the Webb and

McCall procedure may be used to identify and quantify the Aroclors. 16

13.3 For multicomponent mixtures (chlordane, toxaphene, and PCBs) match retention times

of peaks in the standards with peaks in the sample. Quantitate every identifiable peak

unless interference with individual peaks persist after cleanup. Add peak height or peak

area of each identified peak in the chromatogram. Calculate as total response in the

sample versus total response in the standard.

13.4 Report results in μg/L without correction for recovery data. All QC data obtained

should be reported with the sample results.

14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a

substance that can be measured and reported with 99% confidence that the value is above

zero. The MDL concentrations listed in Table 1 were obtained using reagent water. 1 17

Similar results were achieved using representative wastewaters. The MDL actually

achieved in a given analysis will vary depending on instrument sensitivity and matrix

effects.

14.2 This method has been tested for linearity of spike recovery from reagent water and has

been demonstrated to be applicable over the concentration range from 4 x MDL to 1000

x MDL with the following exceptions: Chlordane recovery at 4 x MDL was low (60%);

Toxaphene recovery was demonstrated linear over the range of 10 x MDL to 1000 x

MDL.17

14.3 This method was tested by 20 laboratories using reagent water, drinking water, surface

water, and three industrial wastewaters spiked at six concentrations. Concentrations 18

used in the study ranged from 0.5-30 μg/L for single-component pesticides and from 8.5-

400 μg/L for multicomponent parameters. Single operator precision, overall precision,

and method accuracy were found to be directly related to the concentration of the

parameter and essentially independent of the sample matrix. Linear equations to describe

these relationships are presented in Table 4.
References

1. 40 CFR Part 136, Appendix B.

2. “Determination of Pesticides and PCBs in Industrial and Municipal Wastewaters,” EPA

600/4-82-023, National Technical Information Service, PB82-214222, Springfield, Virginia

22161, April 1982.

3. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation

of Sample Containers and for Preservation of Organic Constituents,” American Society

for Testing and Materials, Philadelphia.

4. Giam, C.S., Chan, H.S., and Nef, G.S. “Sensitive Method for Determination of Phthalate

Ester Plasticizers in Open-Ocean Biota Samples,” Analytical Chemistry, 47, 2225 (1975).

5. Giam, C.S. and Chan, H.S. “Control of Blanks in the Analysis of Phthalates in Air and

Ocean Biota Samples,” U.S. National Bureau of Standards, Special Publication 442, pp.

701-708, 1976.

6. “Carcinogens-Working With Carcinogens,” Department of Health, Education, and

Welfare, Public Health Service, Center for Disease Control, National Institute for

Occupational Safety and Health, Publication No. 77-206, August 1977.

7. “OSHA Safety and Health Standards, General Industry,” (29 CFR Part 1910),

Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

8. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication,

Committee on Chemical Safety, 3rd Edition, 1979.

9. Mills, P.A. “Variation of Florisil Activity: Simple Method for Measuring Absorbent

Capacity and Its Use in Standardizing Florisil Columns,” Journal of the Association of

Official Analytical Chemists, 51, 29, (1968).

10. Provost, L.P. and Elder, R.S. “Interpretation of Percent Recovery Data,” American

Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two

times the value 1.22 derived in this report.)

11. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling

Water,” American Society for Testing and Materials, Philadelphia.

12. “Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine,

Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020,

U.S. Environmental Protection Agency, Environmental Monitoring and Support

Laboratory, Cincinnati, Ohio 45268, March 1979.

13. Goerlitz, D.F. and Law, L.M. Bulletin for Environmental Contamination and Toxicology, 6,

9 (1971).
14. “Manual of Analytical Methods for the Analysis of Pesticides in Human and

Environmental Samples,” EPA-600/8-80-038, U.S. Environmental Protection Agency,

Health Effects Research Laboratory, Research Triangle Park, North Carolina.

15. Burke, J.A. “Gas Chromatography for Pesticide Residue Analysis; Some Practical

Aspects,” Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).

16. Webb, R.G. and McCall, A.C. “Quantitative PCB Standards for Election Capture Gas

Chromatography,” Journal of Chromatographic Science, 11, 366 (1973).

17. “Method Detection Limit and Analytical Curve Studies, EPA Methods 606, 607, and 608,”

Special letter report for EPA Contract 68-03-2606, U.S. Environmental Protection Agency,

Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, June 1980.

18. “EPA Method Study 18 Method 608-Organochlorine Pesticides and PCBs,” EPA

600/4-84-061, National Technical Information Service, PB84-211358, Springfield, Virginia

22161, June 1984.
Table 1—Chromatographic Conditions and Method Detection Limits

Parameter detection limit

Retention time (min) Method

Column 1 Column 2 (μg/L)

"-BHC ............................... 1.35 1.82 0.003

(-BHC ............................... 1.70 2.13 0.004

$-BHC ............................... 1.90 1.97 0.006

Heptachlor ........................... 2.00 3.35 0.003

*-BHC ............................... 2.15 2.20 0.009

Aldrin ............................... 2.40 4.10 0.004

Heptachlor epoxide ..................... 3.50 5.00 0.083

Endosulfan I .......................... 4.50 6.20 0.014

4,4'-DDE ............................. 5.13 7.15 0.004

Dieldrin .............................. 5.45 7.23 0.002

Endrin ............................... 6.55 8.10 0.006

4,4'-DDD ............................. 7.83 9.08 0.011

Endosulfan II ......................... 8.00 8.28 0.004

4,4'-DDT ............................. 9.40 11.75 0.012

Endrin aldehyde ....................... 11.82 9.30 0.023

Endosulfan sulfate ...................... 14.22 10.70 0.066

Chlordane . . . . . . . . . . . . . . . . . . . . . . . . . . . . mr mr 0.014

Toxaphene . . . . . . . . . . . . . . . . . . . . . . . . . . . . mr mr 0.240

PCB-1016 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mr mr nd

PCB-1221 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mr mr nd

PCB-1232 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mt mr nd

PCB-1242 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mr mr 0.065

PCB-1248 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mr mr nd

PCB-1254 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mr mr nd

PCB-1260 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mr mr nd

Column 1 conditions: Supelcoport (100/120 mesh) coated with 1.5% SP-2250/1.95% SP-2401

packed in a 1.8 m long x 4 mm ID glass column with 5% methane/95% argon carrier gas at

60 mL/min. flow rate. Column temperature held isothermal at 200°C, except for PCB-1016

through PCB-1248, should be measured at 160°C.

Column 2 conditions: Supelcoport (100/120 mesh) coated with 3% OV-one packed in a

1.8 m long x 4 mm ID glass column with 5% methane/95% argon carrier gas at 60 mL/min.

flow rate. Column temperature held isothermal at 200°C for the pesticides; at 140°C for

PCB-1221 and 1232; and at 170°C for PCB-1016 and 1242-1268.

mr = Multiple peak response. See Figures 2-10.

nd = Not determined.
Table 2—Distribution of Chlorinated Pesticides and PCBs into Florisil Column Fractions2

Parameter Percent recovery by fractiona

12 3

Aldrin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . .

"-BHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . .

$-BHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 . . . . . . . . . . . . . .

*-BHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 . . . . . . . . . . . . . .

(-BHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . .

Chlordane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . .

4,4'-DDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 . . . . . . . . . . . . . .

4,4'-DDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 . . . . . . . . . . . . . .

4,4'-DDT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . .

Dieldrin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 100 . . . . . . .

Endosulfan I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 64 . . . . . . .

Endosulfan II . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 7 91

Endosulfan sulfate . . . . . . . . . . . . . . . . . . . . . . . . . 0 0 106

Endrin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 96 . . . . . . .

Endrin aldehyde . . . . . . . . . . . . . . . . . . . . . . . . . . 0 68 26

Heptachlor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . .

Heptachlor epoxide . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . .

Toxaphene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 . . . . . . . . . . . . . .

PCB-1016 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 . . . . . . . . . . . . . .

PCB-1221 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 . . . . . . . . . . . . . .

PCB-1232 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 4 . . . . . . .

PCB-1242 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 . . . . . . . . . . . . . .

PCB-1248 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 . . . . . . . . . . . . . .

PCB-1254 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 . . . . . . . . . . . . . .

PCB-1260 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 . . . . . . . . . . . . . .

Eluant composition: a

Fraction 1 - 6% ethyl ether in hexane.

Fraction 2 - 15% ethyl ether in hexane.

Fraction 3 - 50% ethyl ether in hexane.
Table 3—QC Acceptance Criteria—Method 608

Parameter conc. for s P, P

Test Limit Range for

(μg/L) (μg/L) %)

Range for

 (μg/L) s

Aldrin . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 0.42 1.08 - 2.24 42 - 122

"-BHC . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 0.48 0.98 - 2.44 37 - 134

$-BHC . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 0.64 0.78 - 2.60 17- 147

*-BHC . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 0.72 1.01 - 2.37 19 - 140

(-BHC . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 0.46 0.86 - 2.32 32 - 127

Chlordane . . . . . . . . . . . . . . . . . . . . . . 50 10.0 27.6 - 54.3 45 - 119

4,4'-DDD . . . . . . . . . . . . . . . . . . . . . . . 10 2.8 4.8 - 12.6 31 - 141

4,4'-DDE . . . . . . . . . . . . . . . . . . . . . . . 2.0 0.55 1.08 - 2.60 30 - 145

4,4'-DDT . . . . . . . . . . . . . . . . . . . . . . . 10 3.6 4.6 - 13.7 25 - 160

Dieldrin . . . . . . . . . . . . . . . . . . . . . . . . 2.0 0.76 1.15 - 2.49 36 - 146

Endosulfan I . . . . . . . . . . . . . . . . . . . . 2.0 0.49 1.14 - 2.82 45 - 153

Endosulfan II . . . . . . . . . . . . . . . . . . . 10 6.1 2.2 - 17.1 D - 202

Endosulfan Sulfate . . . . . . . . . . . . . . . 10 2.7 3.8 - 13.2 26 - 144

Endrin . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.7 5.1 - 12.6 30 - 147

Heptachlor . . . . . . . . . . . . . . . . . . . . . 2.0 0.40 0.86 - 2.00 34 - 111

Heptachlor epoxide . . . . . . . . . . . . . . . 2.0 0.41 1.13 - 2.63 37 - 142

Toxaphene ...................... 50.0 12.7 27.8 - 55.6 41 - 126

PCB-1016 . . . . . . . . . . . . . . . . . . . . . . . 50 10.0 30.5 - 51.5 50 - 114

PCB-1221 . . . . . . . . . . . . . . . . . . . . . . . 50 24.4 22.1 - 75.2 15 - 178

PCB-1232 . . . . . . . . . . . . . . . . . . . . . . . 50 17.9 14.0 - 98.5 10 - 215

PCB-1242 . . . . . . . . . . . . . . . . . . . . . . . 50 12.2 24.8 - 69.6 39 - 150

PCB-1248 . . . . . . . . . . . . . . . . . . . . . . . 50 15.9 29.0 - 70.2 38 - 158

PCB-1254 . . . . . . . . . . . . . . . . . . . . . . . 50 13.8 22.2 - 57.9 29 - 131

PCB-1260 . . . . . . . . . . . . . . . . . . . . . . . 50 10.4 18.7 - 54.9 8 - 127

s = Standard deviation of four recovery measurements, in μg/L (Section 8.2.4).

 = Average recovery for four recovery measurements, in μg/L (Section 8.2.4).

P, P = Percent recovery measured (Section 8.3.2, Section 8.4.2). s

D = Detected; result must be greater than zero.

NOTE: These criteria are based directly upon the method performance data in Table 4.

Where necessary, the limits for recovery have been broadened to assure

applicability of the limits to concentrations below those used to develop Table 4.
Table 4—Method Accuracy and Precision as Functions of Concentration—Method 608

Parameter recovery, X' precision, s ' precision, S'

Accuracy, as Single analyst Overall

(μg/L) (μg/L) (μg/L) r

Aldrin ............................... 0.81C+0.04 0.16 - 0.04 0.20 - 0.01

"-BHC ............................... 0.84C+0.03 0.13 +0.04 0.23 - 0.00

$-BHC ............................... 0.81C+0.07 0.22 - 0.02 0.33 - 0.05

*-BHC ............................... 0.81C+0.07 0.18 +0.09 0.25 +0.03

(-BHC ............................... 0.82C - 0.05 0.12 +0.06 0.22 +0.04

Chlordane ............................ 0.82C - 0.04 0.13 +0.13 0.18 +0.18

4,4'-DDD ............................. 0.84C+0.30 0.20 - 0.18 0.27 - 0.14

4,4'-DDE ............................. 0.85C+0.14 0.13 +0.06 0.28 - 0.09

4,4'-DDT ............................. 0.93C - 0.13 0.17 +0.39 0.31 - 0.21

Dieldrin .............................. 0.90C+0.02 0.12 +0.19 0.16 +0.16

Endosulfan I ......................... 0.97C+0.04 0.10 +0.07 0.18 +0.08

Endosulfan II ......................... 0.93C+0.34 0.41 - 0.65 0.47 - 0.20

Endosulfan Sulfate ..................... 0.89C - 0.37 0.13 +0.33 0.24 +0.35

Endrin ............................... 0.89C - 0.04 0.20 +0.25 0.24 +0.25

Heptachlor ........................... 0.69C+0.04 0.06 +0.13 0.16 +0.08

Heptachlor epoxide ..................... 0.89C+0.10 0.18 - 0.11 0.25 - 0.08

Toxaphene ............................ 0.80C+1.74 0.09 +3.20 0.20 +0.22

PCB-1016 ............................. 0.81C+0.50 0.13 +0.15 0.15 +0.45

PCB-1221 ............................. 0.96C+0.65 0.29 - 0.76 0.35 - 0.62

PCB-1232 ............................ 0.91C+10.79 0.21 - 1.93 0.31 +3.50

PCB-1242 ............................. 0.93C+0.70 0.11 +1.40 0.21 +1.52

PCB-1248 ............................. 0.97C+1.06 0.17 +0.41 0.25 - 0.37

PCB-1254 ............................. 0.76C+2.07 0.15 +1.66 0.17 +3.62

PCB-1260 ............................. 0.66C+3.76 0.22 - 2.37 0.39 - 4.86

X' = Expected recovery for one or more measurements of a sample containing a

concentration of C, in μg/L.

sr' = Expected single analyst standard deviation of measurements at an average

concentration found of , in μg/L.

S' = Expected interlaboratory standard deviation of measurements at an average

concentration found of , in μg/L.

C = True value for the concentration, in μg/L.

 = Average recovery found for measurements of samples containing a concentration of C,

in μg/L.