The U.S. Environmental Protection Agency's New Methods for Detecting Pesticides in Ground Water	

WGS-Mail Stop 412	July 26, 1990

OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM NO. 90.12

SUBJECT:  The U.S. Environmental Protection Agency's New Methods 
          for Detecting Pesticides in Ground Water:  Status of 
          Method Promulgation and Comparison with Current 
          U.S. Geological Survey National Water-Quality Laboratory 
          Methods.

The purposes of this memorandum are to:

1.  Describe the Environmental Protection Agency's (EPA) new 
pesticide methods developed initially for the National Pesticide 
Survey,

2.  Describe the status of the EPA-methods promulgation, and

3.  Compare the EPA methods to current pesticide analytical 
methods of the National Water-Quality Laboratory (NWQL) of the 
U.S. Geological Survey (USGS).

The detailed descriptions and comparisons are presented in 
Attachment 1, which was prepared by Bill Foremen, Methods Research 
and Development Program, of the NWQL.

To support the National Pesticide Survey, the EPA Office of 
Drinking Water Technical Support Division and the Environmental 
Monitoring Systems Laboratory (EMSL)-Cincinnati in conjunction 
with Battelle-Columbus Laboratories developed six new pesticide 
methods.  Five of the methods were designed as multi-residue 
methods applicable to a number of pesticides and a few major 
degradation products.  The sixth method was developed specifically 
for ethylene thiourea, a degradation product of a family of 
fungicides (see below).  All six methods were developed for 
relatively clean water matrices, including drinking water and most 
ground waters.  Summarized descriptions of the analytical 
procedures for the six EPA methods are provided in Appendix A of 
Attachment 1.  To date, none of these methods have been 
implemented at the USGS's NWQL.

Four of the EPA methods (507, 508, 515.1, and 531.1) are 
applicable to drinking water regulations as proposed in the May 
22, 1989, issue of the Federal Register.  The four proposed 
methods also can be found in the report "Methods for the 
Determination of Organic Compounds in Drinking Water" (EPA, 1988).  
These four methods are anticipated to undergo final promulgation 
in the Federal Register in December 1990, at which time they can 
be used to fulfill appropriate testing requirements under drinking 
water regulations.

Tables 1-5 of Attachment 1 list the target analytes determined 
under the five EPA multi-residue methods, along with the analyte 
estimated detection limit (EDL) for the EPA method.  This EDL is 
defined as either the method detection limit (MDL) or a level of 
compound in a sample yielding a chromatographic peak in the final 
extract with a signal-to-noise ratio of approximately 5, whichever 
value is higher.  The MDL is calculated from the standard 
deviation of replicate measurements, and is defined as the minimum 
concentration of a substance that can be identified, measured, and 
reported with 99% confidence that the analyte concentration is 
greater than zero.  These EDL or MDL are intended to provide an 
indication of the capability of the method.  (For more information 
on the EPA MDL determination see Code of Federal Regulations 
(1989)).  EDL values in Tables 1-5 are based on measurements made 
in a single laboratory.

Also included in Tables 1-5 of Attachment 1 are the laboratory 
schedules (methods) under which the analytes are determined at the 
NWQL, where applicable.  Summarized descriptions of these NWQL 
methods are also provided in Appendix A.  The NWQL methods make no 
distinction as to whether the sample matrix is a surface- or 
ground-water sample.  For those NWQL schedule numbers without a 
footnote in the tables, the analyte is a schedule target compound 
which is routinely analyzed and reported via the PRIME computer to 
the Districts for storage in the National Water Information System 
(NWIS) data base.  All analytes which have footnotes given with 
the NWQL schedule numbers are method add-on compounds that have 
been included as a request of the National Water-Quality 
Assessment (NAWQA) Program (noted as a RNAWQA add-onS), or as a 
specific project request having a high enough sample demand for 
the NWQL to add the analyte to the schedule (noted as a Rmethod 
add-onS).  These footnotes provide additional information 
regarding the current availability status of these add-on 
compounds to all USGS projects.

The NWQL analyte reporting limit is also provided in Tables 1-5 
for comparison with the EPA method EDL.  Each NWQL reporting limit 
has been set as the lowest measured concentration of a constituent 
that may be reliably reported using the analytical method.  The 
NWQL reporting limit is a value set somewhat higher than the 
method detection limit established when the method was originally 
developed at the NWQL.  The NWQL uses these reporting limits 
because of unpredictable matrix effects on method detection 
limits.  While EPA uses statistical precision as a basis for 
establishing MDLs and EDLs, the agency does not establish 
reporting limits.  See page 11 for a discussion of the 
comparability of EPA's MDLs and EDLs to NWQL's reporting limits.

                                    David A. Rickert
                                    Chief, Office of Water Quality

This memorandum does not supersede any previous Office of Water 
Quality memorandum.

Key Words:  Methods, National Water-Quality Laboratory, Pesticides

WRD Distribution:  A, B. S, FO, PO

                           ATTACHMENT 1

The Environmental Protection Agency's New Methods for Detecting 
Pesticides in Ground Water:  Status of Method Promulgation and 
Comparison with Current U.S. Geological Survey National Water-
Quality Laboratory Methods.

EPA METHOD 507 -- Determination of Nitrogen- and Phosphorus-
                  Containing Pesticides in Water by Gas 
                  Chromatography with a Nitrogen-Phosphorus 
                  Detector

Table 1.  Comparison of EPA Method 507 and NWQL Schedule Target 
Analytes
_________________________________________________________________
    EPA              Estimated Detection  NWQL         NWQL
	Target Analyte             Level     Schedule No. Reporting Limit
                          (5g/L)                      (5g/L)
_________________________________________________________________
Alachlor                   0.38          1389           0.1
Ametryn                    2             1389           0.1
Atraton                    0.6
Atrazine                   0.13          1389           0.1
Bromacil                   2.5           1389b            0.1
Butachlor                  0.38          1389b            0.1
Butylate                   0.15          1389b            0.1
Carboxin                   0.6           1389b            0.1
Chlorpropham               0.5
Cycloate                   0.25          1389b            0.1
Diazinon*a                    0.25          1319           0.01
Dichlorvos                 2.5
Diphenamid                 0.6           1389b            0.1
Disulfoton*                0.3           1319c            0.01
Disulfoton sulfone*        3.8
Disulfoton sulfoxide*a      0.38
EPTC                       0.25
Ethoprop                   0.19
Fenamiphos                 1
Fenarimol                  0.38
Fluridone                  3.8
Hexazinone                 0.76          1389b            0.1
Merphos*                   0.25
Methyl paraoxon            2.5

Table 1.  Comparison of EPA Method 507 and NWQL Schedule Target 
Analytes--(continued)
__________________________________________________________________
    EPA              Estimated Detection  NWQL           NWQL
	Target Analyte             Level      Schedule No. Reporting Limit
                          (5g/L)                        (5g/L)
__________________________________________________________________
Metolachlor                 0.75          1389           0.2
Metribuzin                  0.15          1389           0.1
Mevinphos                   5
MGK 264                     0.5
Molinate                    0.15
Napropamide                 0.25
Norflurazon                 0.5
Pebulate                    0.13
Prometon                    0.3           1389           0.1
Prometryn                   0.19          1389           0.1
Pronamide*a                    0.76
Propazine                   0.13          1389           0.1
Simazine                    0.075         1389           0.1
Simetryn                    0.25          1389           0.1
Stirofos                    0.76
Tebuthiuron                 1.3
Terbacil                    4.5           1389b            0.1
Terbufos*a                     0.5
Terbutryn                   0.25
Triademefon                 0.65
Tricyclazole                1
Vernolate                   0.13          1389b            0.1
__________________________________________________________________

* These compounds, although identified, are not quantitated in 
the EPA method because control over precision has not been 
accomplished.

a/The EPA method notes that the compound exhibits aqueous 
instability.  Therefore, quantitative analysis for this compound 
may not be possible.

b/NAWQA add-on compound not reported via the PRIME.  This 
compound is currently available to non-NAWQA projects as a 
prearranged custom analysis.  NOTE:  These nine NAWQA add-on 
compounds to schedule 1389 are currently undergoing further method 
recovery and precision tests at the NWQL.  Upon completion, those 
add-on compounds shown amenable to the method will be routinely 
available to all WRD projects and reported through the PRIME.  In 
addition, propachlor is also being evaluated under schedule 1389, 
and is currently available as a custom analysis.  Propachlor is a 
target analyte of EPA method 508 below.
c/A method add-on compound routinely reported via the PRIME to 
all projects.

EPA METHOD 508 --Determination of Chlorinated Pesticides in Water 
                 by Gas Chromatography with an Electron Capture 
                 Detector

Table 2.  Comparison of EPA Method 508 and NWQL Schedule Target 
          Analytes
_________________________________________________________________
    EPA             Estimated Detection  NWQL          NWQL
	Target Analyte             Level     Schedule No. Reporting Limit
                          (5g/L)                      (5g/L)
_________________________________________________________________
Aldrin                     0.075         1324           0.01
Chlordane-alpha            0.0015
Chlordane-gamma            0.0015
Chlorneb                   0.5
Chlorobenzilate*             5
Chlorthalonil              0.025
DCPA  (Dacthal)            0.025           79b            0.01
4,4'-DDD                   0.0025         1324          0.01
4,4'-DDE                   0.01           1324          0.01
4,4'-DDT                   0.06           1324          0.01
Dieldrin                   0.02           1324          0.01
Endosulfan I               0.015          1324          0.01
Endosulfan II              0.024
Endosulfan sulfate         0.015
Endrin                     0.015          1324          0.01
Endrin aldehyde            0.025
Etridiazole                0.025
HCH-alpha                  0.025          1324c          0.01
HCH-beta                   0.01           1324c          0.01
HCH-delta*                 0.01           1324c          0.01
HCH-gamma (Lindane)        0.015          1324          0.01
Heptachlor                 0.01           1324          0.01
Heptachlor epoxide         0.015          1324          0.01
Hexachlorobenzene          0.0077         1324c           0.01
Methoxychlor               0.05           1324           0.01
cis-Permethrin             0.5
trans-Permethrin           0.5
Propachlor                 0.5            1389d            0.1
Trifluralin                0.025          1389           0.1

Table 2.  Comparison of EPA Method 508 and NWQL Schedule Target 
          Analytes--(continued)
__________________________________________________________________
    EPA              Estimated Detection  NWQL           NWQL
	Target Analyte              Level     Schedule No. Reporting Limit
                            (5g/L)                      (5g/L)
__________________________________________________________________
Aroclor 1016                NAa             1364           0.1
Aroclor 1221                NAa             1364           0.1
Aroclor 1232                NAa             1364           0.1
Aroclor 1242                NAa             1364           0.1
Aroclor 1248                NAa             1364           0.1
Aroclor 1254                NAa             1364           0.1
Aroclor 1260                NAa             1364           0.1
Toxaphene                   NAa             1324           1.0
Technical Chlordane         NAa             1324           0.1
__________________________________________________________________
* These compounds, although identified, are not quantitated in 
the EPA method because control over precision has not been 
accomplished.
a/NA = Not  Available.  These complex multicomponent mixtures 
are included in the list, because the extraction conditions are 
the same as those used in EPA method 608, which does measure the 
multicomponent constituents as mixture equivalents in terms of 
commercial polychlorinated biphenyl (PCB) mixtures (Aroclors), 
technical toxaphene, and technical chlordane.  However, no 
recovery data were collected for these constituents during 
development of EPA method 508.  NOTE:  EPA method 508 does not 
represent a good method for determining these complex mixtures 
since liquid chromatography cleanup/fractionation using silica and 
alumina columns is not included.  NWQL schedules 1364 and 1324 
(see Appendix A) do include alumina cleanup, and additional class 
fractionation of PCBs from the major components of chlordane and 
toxaphene is available upon request for those projects requiring 
more detailed analysis of these contaminants.
b/Method add-on compound not reported via the PRIME.  This 
compound is currently available as a prearranged custom analysis.  
Schedule 79 also determines the DCPA monoacid and diacid 
metabolites [see Table 3 footnote (a)] along with DCPA.  EPA 
method 508 does not include these acid metabolites, however, these 
metabolites are included in EPA method 515.1.
c/Method add-on compound not reported via the PRIME.  This 
compound currently is available as a prearranged custom analysis.
d/NAWQA add-on compound reported via the PRIME.  This compound 
currently is available to non-NAWQA projects as a prearranged 
custom analysis.  Propachlor also currently is undergoing further 
method recovery and precision tests at the NWQL under schedule 
1389 [see Table 1 footnote (b)].

EPA METHOD 515.1 --  Determination of Chlorinated Acids in Water 
                     by Gas Chromatography with an Electron 
                     Capture Detector

Table 3.  Comparison of EPA Method 515.1 and NWQL Schedule Target 
          Analytes
__________________________________________________________________
    EPA              Estimated Detection  NWQL           NWQL
	Target Analyte             Level      Schedule No. Reporting Limit
                           (5g/L)                       (5g/L)
__________________________________________________________________
Acifluorfen*                0.096
Bentazon                    0.2
Chloramben*                 0.093          79b             0.1
2,4-D                       0.2            79            0.01
Dalapon*                    1.3
2,4-DB                      0.8
DCPA and acid metabolitesa   0.02           79b            0.01
Dicamba                     0.081          79            0.01
3,5-Dichlorobenzoic acid    0.061
Dichlorprop  (2,4-DP)       0.26           79            0.01
Dinoseb                     0.19
5-Hydroxydicamba            0.04
4-Nitrophenol*              0.13
Pentachlorophenol  (PCP)    0.076
Picloram                    0.14           79            0.01
2,4,5-T                     0.08           79            0.01
2,4,5-TP  (Silvex)          0.075          79            0.01
__________________________________________________________________
*These compounds, although identified, are not quantitated in the 
EPA method because control over precision has not been accomplished.
a/The monoacid and diacid metabolites of DCPA (Dacthal) are 
included in both EPA method 515.1 and NWQL schedule 79.
b/Method add-on compound not reported via the PRIME.  This 
compound currently is available as a prearranged custom analysis.

EPA METHOD 531.1 -- Measurement of N-Methylcarbamoyloximes and N-
                    Methylcarbamates in Water by Direct Aqueous 
                    Injection High Performance Liquid 
                    Chromatography (HPLC) with Post Column 
                    Derivatization

Table 4.  Comparison of EPA Method 531.1 and NWQL Schedule Target 
          Analytes
__________________________________________________________________
    EPA              Estimated Detection  NWQL          NWQL
	Target Analyte              Levela    Schedule No  Reporting Limit
                            (5g/L)                     (5g/L)
__________________________________________________________________
Aldicarb                     1.0          1359b           0.5
Aldicarb sulfone             2.0
Aldicarb sulfoxide           2.0
Baygon (Propoxur)            1.0          1359b           0.5
Carbaryl                     2.0          1359          0.5
Carbofuran                   1.5          1359b           0.5
3-Hydroxycarbofuran          2.0
Methiocarb                   4.0          1359b           0.5
Methomyl                     0.5          1359          0.5
Oxamyl                       2.0
__________________________________________________________________

a/EDL values approximately 2-4 fold lower can now be achieved 
due to improved sensivity of the fluorescence detector.  Thus, EPA 
EDL values and NWQL reporting limits are similar.

b/NAWQA add-on compound now routinely available to non-NAWQA 
projects as well, but not reported via the PRIME.

                    DRAFT EPA PESTICIDE METHODS

The two other methods developed for use in the EPA National 
Pesticide Survey are shown below.  EPA draft method #4 has 
undergone interlaboratory validation, and following review the EPA 
has decided not to propose use of this method because there does 
not appear to be sufficient interest within the EPA programs for 
the majority of method target analytes (personal communication 
from David Munch, EPA EMSL-Cincinnati, May 1990).  EPA draft 
method #6 is presently undergoing interlaboratory validation and 
review, and EPA still intends to propose use of this method in the 
Federal Register.

EPA DRAFT METHOD #4 --  Determination of Pesticides in Ground 
                        Water by High Performance Liquid 
                        Chromatography with an Ultraviolet 
                        Detector

Table 5.  Comparison of EPA Draft Method #4 and NWQL Schedule 
          Target Analytes
__________________________________________________________________
     EPA             Estimated Detection  NWQL           NWQL
Target Analyte             Level      Schedule No. Reporting Limit
                           (5g/L)                        (5g/L)
__________________________________________________________________
Atrazine deethylated        0.25
Barban                      0.50
Carbofuran phenol           1.8
Cyanazine                   0.58          1389            0.1
Diuron                      0.070
Fenamiphos sulfone          5.7
Fenamiphos sulfoxide        1.0
Fluometuron                 0.10
3-Ketocarbofuran            0..25
Linuron                     0.25
Metribuzin DAa                 0.21
Metribuzin DKa                 0.10
Metribuzin DADKa               2.5
Neburon                     0.15
Pronamide metabolite        0.81
Propanil                    0.067
Propham                     0.75           1359           0.5
Swep                        0.75
__________________________________________________________________
	aDA = deamino-metabolite.  DK = diketo-metabolite.  
   DADK = deamino, diketo-metabolite.

EPA DRAFT METHOD #6 --  Determination of Ethylene Thiourea (ETU) 
                        in Ground Water by Gas Chromatography with
                        a Nitrogen-Phosphorus Detector

Ethylene thiourea (ETU) is a major degradation product of a family 
of organometallic fungicides used on crops.  All of these 
organometallic compounds are complexes of transition metals as 
ethylene-bis-dithiocarbamic acid salts.  Examples include Zineb 
(containing zinc) and Maneb (containing manganese).  ETU is of 
interest because it is highly soluble in water and is a suspected 
carcinogen and a teratogen.  The EPA draft EDL value determined by 
Battelle-Columbus Laboratories for ETU is 5 5g/L.  The NWQL does 
not analyze for ethylene thiourea.

ADDITIONAL PESTICIDE ANALYTES IN THE NWQL SCHEDULES

Table 6 lists additional pesticides available under NWQL schedules 
1319, 1324, and 1359 that are not target analytes of the six EPA 
methods above.  NWQL schedules 1389 and 79 do not contain any 
additional target analytes (or add-ons) not determined under EPA 
methods 507, 508, 515.1 and Draft Method #4.

Table 6.  Additional NWQL Pesticide Schedule Analytes
_____________________________________________________________
Schedule No.                 Analyte          Reporting Limit
                                                   (5g/L)
_____________________________________________________________

1319a                     Chlorpyrifos                 0.01
1319                   DEF  (Butifos)               0.01
1319                   Ethion                       0.01
1319a                     Fonofos                      0.01
1319                   Malathion                    0.01
1319b                     Methyl azinphos  (Guthion)   0.1
1319                   Parathion (-ethyl)           0.01
1319                   Parathion-methyl             0.01
1319                   Phorate                      0.01
1319                   Trithion                     0.01
1319                   Trithion-methyl              0.01

1324                   Mirex                        0.01
1324                   Perthane (Ethylan)           0.01

1359c                     1-Naphthold                      0.5
_____________________________________________________________
aMethod add-on compound routinely reported to all projects 
 but not via the PRIME.
bMethod add-on compound not reported via the PRIME.  This  
 compound is currently available as a prearranged custom 
 analysis.
cNAWQA add-on compound now routinely available to non-NAWQA 
 projects as well, but not reported via the PRIME.
dDegradation product of carbaryl.  Although not included in 
 the target analyte list under EPA method 531.1 (Table 4), 
 1-naphthol can be determined by method 531.1.

          COMPARISON OF EPA ESTIMATED DETECTION LIMITS 
                    AND NWQL REPORTING LIMITS 

For a number of analytes in Tables 1-3 above, the NWQL reporting 
limit is either similar to or lower than the EPA EDL by a factor 
of approximately five or less.  In the latter case of lower NWQL 
values, the differences between the NWQL and EPA values are likely 
attributable to differences in the NWQL and EPA methods final 
extract volume from which instrumental analysis is conducted.  EPA 
methods 507, 508, and 515.1 extract 1 liter (L) of water and 
concentrate the extract to a 5 mL final volume, from which a 2 uL 
aliquot is used for instrumental analysis.  The comparable NWQL 
methods (schedules 1389, 1319, 1324, 1364, and 79) all extract 1 L 
of water, but end up at a 1-2 mL final extract volume, from which 
a 2 uL aliquot is analyzed (see Appendix A for procedural 
details).  This theoretically represents a 2.5- to 5-fold 
enhancement in analyte mass introduced to the GC for the NWQL 
methods versus the EPA methods.  For a few other analytes, the 
NWQL reporting limit is nearly an order of magnitude or more lower 
than the EPA EDL, the reasons for which are not obvious but may be 
attributable to chromatographic or detector performance.

It is interesting to note the differences between the EPA 531.1 
EDL and the NWQL 1359 reporting limits given in Table 4.  EPA 
531.1 requires minimal sample preparation steps and no 
preconcentration of the water prior to instrumental analysis by 
HPLC with fluorescence detection.  However, the method is limited 
to N-methylcarbamates and N-methylcarbamoyloximes because of the 
requirement to form methyl amine in the post-column derivatization 
step.  On the other hand, NWQL 1359 requires time-consuming sample 
preparation and preconcentration steps prior to analysis by HPLC 
with photodiode array ultraviolet detection (see Appendix A for 
procedural details).  Considering differences in concentration 
factors and instrument injection volumes, NWQL 1359 should 
theoretically introduce 714 times more analyte mass onto the HPLC 
column than EPA 531.1.  Table 4 shows that the NWQL reporting 
limits are only up to a factor of eight lower than the EPA 531.1 
EDL.  The lack of a much greater difference in EPA EDL and NWQL 
reporting limits is due to the much greater sensitivity of the 
fluorescence detector versus the ultraviolet detector.  
(Currently, an approximately 2-4 fold increase in sensitivity of 
method 531.1 compounds can be achieved due to improved sensitivity 
of the fluorescence detector.)  It is important to note that NWQL 
1359 is not limited only to N-methylcarbamates and N-
methylcarbamoyloximes, and can theoretically be used to analyze 
for other non-N-methyl carbamates and other analytes, assuming 
good performance of the sample preparation steps and HPLC 
separation.  However, at present the only non-N-methyl compounds 
analyzed for under 1359 are propham (Table 5) and 1-naphthol 
(Table 6), though 1-naphthol also can be determined under EPA 
method 531.1 [see Table 6 footnote (c)].

In Table 5, the EPA EDL and the NWQL reporting limit for propham 
are similar.  The difference for cyanazine is likely attributable 
to instrumental differences between EPA draft method #4 (HPLC-UV) 
and NWQL 1389 (GC-NPD).

                 USE OF SAMPLE PRESERVATIVES

EPA methods 507, 508, and 515.1 use field addition of 10 mg/L of 
the bactericide mercuric chloride (HgCl2), or any other reagent 
shown to work as well, and 80 mg/L sodium thiosulfate, if residual 
chlorine is present, to the sample bottles prior to shipment to 
the field.  EPA draft methods #4 and #6 call for addition of HgCl2 
only.  These methodUs samples are stored and transported in amber 
glass bottles at 4 deg C. The comparable NWQL methods (schedules 
1389, 1319, 1324, 1364, and 79) likewise call for storing and 
transporting samples in amber glass bottles at 4 deg. C, but do 
not call for addition of any bactericide or residual chlorine 
scavenger.  While HgCl2 may represent an effective bactericide, its 
use in samples targeted for organics analysis is not recommended 
by the Methods Research and Development Program of the NWQL 
because it requires special treatment of the samples to remove the 
Hg before disposal.  Preservation with HgCl2 introduces a 
contamination potential for those projects also collecting water 
samples for Hg analysis, and can interfere with organic 
instrumental analysis under certain conditions (Foreman and 
others, 1990).  HgCl2 is also highly toxic to humans.  It should be 
noted that in the absence of a biocide, studies may need to be 
conducted to determine the stabilities of target analyses in water 
matrices being investigated.  

EPA method 531.1 requires field addition of 1.8 mL 2.5 M 
monochloroacetic acid solution to buffer the 60 mL water sample to 
pH 3.  This is done to help preserve the analytes, since oxamyl, 
3-hydroxycarbofuran, aldicarb sulfoxide, and carbaryl reportedly 
all can degrade (hydrolyze) rapidly in neutral or basic waters at 
room temperature.  The pH adjustment also minimizes analyte 
biodegradation.  The comparable NWQL carbamate method (1359) does 
not incorporate any field pH adjustment to minimize hydrolysis or 
biodegradation.

OTHER COMMENTS ON DIFFERENCES BETWEEN EPA AND NWQL METHODS

Some compounds included in the EPA methods are not currently 
available from NWQL.  EPA 507 represents a potential alternative 
to NWQL 1389, especially if final extract volumes are reduced to 1 
mL or less.  EPA 507 covers all current 1389 analytes (except 
propachlor and trifluralin (EPA 508) and cyanazine (EPA Draft 
Method #4), all three of which should be easily added to EPA 507) 
plus determines 25 additional analytes not currently available at 
the NWQL.  An even greater enhancement to either EPA 507 or 
schedule 1389 would be the substitution of GC with mass 
spectrometric detection (GC-MS operated in the selected ion 
monitoring mode) for the current GC-NPD instrumental method.  The 
Methods Research and Development Program (MRDP) and the Organics 
Program of the NWQL will be implementing a new GC-MS method within 
the next year as an alternative to schedule 1389.

EPA 508 probably does not represent an improvement to NWQL 1324 or 
1364, since no column cleanup/fractionation steps to separate 
complex mixture constituents are included in 508.  It may be 
possible to add the eleven analytes in EPA 508 not determined at 
the NWQL to schedule 1324.

Because of procedural similarities (see Appendix A), the nine 
analytes in EPA 515.1 not presently determined at the NWQL could 
likely be added to NWQL 79.

EPA draft method #4Us target analyte list represents some 
important compounds that various District projects have identified 
as a need, but for which the NWQL does not currently have methods.  
Better method detection limits would be achievable for EPA draft 
method #4 if the final extract volume was reduced.

                         CONTACTS

For additional information regarding the EPA methods or their 
comparison with NWQL methods, please contact Bill Foreman, Methods 
Research and Development Program, NWQL, Arvada, Colorado 80002 at 
FTS-776-9363 or 303-236-9363 or EDOC to WTFOREMAN.  

Please direct all inquiries regarding custom analyses for the 
above NWQL Schedules to Doug Manigold, NWQL Organics Program 
Chief, at FTS-776-5345 or 303-236-5345 or EDOC to DBMANIGOLD.

Project chiefs who may require analytical services for analytes 
not presently offered by the NWQL should make their needs known to 
their Regional Water-Quality Specialist and/or to Richard O. 
Hawkinson, Chief, Branch of Analytical Services, NWQL.

                                                        Appendix A

         PROCEDURAL DETAILS OF THE EPA AND NWQL METHODS

The following summarized descriptions of both the EPA and NWQL 
methods are provided for individuals interested in the actual 
procedures.  Those requiring greater detail regarding EPA methods 
507, 508, 515.1, and 531.1 should consult EPA (1988).  The EPA 
draft methods #4 and #6 have not been officially published.  The 
NWQL schedule procedures described below are from Wershaw and 
others (1987), and include some updated procedural revisions.

                      EPA SCHEDULES

EPA METHOD 507 -- Determination of Nitrogen- and Phosphorus
                  Containing Pesticides in Water by Gas 
                  Chromatography with a Nitrogen-Phosphorus 
                  Detector

An approximate 1 L volume water sample is fortified with a 
surrogate standard solution, the pH is adjusted to 7 with 
phosphate buffer, and 100 g of NaCl is added.  The sample is 
extracted three times with 60 mL portions each of dichloromethane 
by shaking in a separatory funnel and the solvent portions 
combined.  An automated extraction method is also permitted.  The 
extract is dried using anhydrous sodium sulfate, and concentrated 
using a Kuderna-Danish (K-D) apparatus and solvent exchanged to 
methyl t-butyl ether to give a final extract volume of 5 mL.  An 
internal injection standard solution is added to the extract if an 
internal standard calibration procedure is used.  The extract is 
then analyzed by fused silica capillary column gas chromatography 
(GC) with a nitrogen-phosphorus detector (NPD) by injecting a 2 5L 
aliquot of the extract onto a GC column.  The primary column is a 
30 m x 0.25 mm internal diameter (ID) column coated with a 0.25 5m 
film thickness of 5% phenyl methylpolysiloxane (J & W Scientific 
DB-5 column or equivalent).  The secondary confirmation column is 
a 14% cyanopropylphenyl methylpolysiloxane (J & W Scientific DB-
1701 column or equivalent).

EPA METHOD 508 -- Determination of Chlorinated Pesticides in Water 
                  by Gas Chromatography with an Electron Capture 
                  Detector

This method is identical to Method 507 in all respects, except 
that the analytes are determined by capillary column GC with an 
electron capture detector (ECD).

EPA METHOD 515.1 --  Determination of Chlorinated Acids in Water 
                     by Gas Chromatography with an Electron 
                     Capture Detector

An approximate 1 L volume water sample is placed in a separatory 
funnel.  The sample is fortified with a surrogate standard 
solution, 250 g of NaCl is added, and the pH is adjusted to 3 12 
with 6 N NaOH to hydrolyze any chlorinated acid esters present.  
The sample is periodically shaken over a 1 hour period during this 
hydrolysis step.  Extraneous base/neutral organic material is 
removed by extracting the sample three times with 60 mL portions 
each of dichloromethane in the separatory funnel and discarding 
the solvent portions.  An automated extraction method is also 
permitted.  The sample is acidified to pH 2 2 using 12 N H2SO4, 
and the chlorinated acids are extracted three times with 60 mL 
portions each of diethyl ether by shaking in a separatory funnel 
and the solvent portions combined.  The extract is dried using 
acidified anhydrous sodium sulfate, poured through acid washed 
glass wool into a K-D apparatus, and concentrated and solvent 
exchanged to methyl t-butyl ether to a 5 mL final volume.  The 
chlorinated acids are then converted to their methyl ester 
derivatives using either a gaseous or solution diazomethane 
derivatization procedure.  A Florisil cleanup procedure can be 
included at this point to eliminate additional interferents, if 
encountered.  An internal injection standard solution is added to 
the extract if an internal standard calibration procedure is used.  
The final extract (now at a 5 or 10 mL final volume depending on 
whether the Florisil cleanup step is omitted or used, 
respectively) is analyzed by capillary column GC-ECD using GC 
columns and conditions identical to Methods 507 and 508.

EPA METHOD 531.1 --  Measurement of N-Methylcarbamoyloximes and 
                     N-Methylcarbamates in Water by Direct Aqueous 
                     Injection High Performance Liquid 
                     Chromatography (HPLC) with Post Column 
                     Derivatization

A 60 mL water sample is collected and buffered to pH 3 in the 
field using 2.5 M monochloroacetic acid buffer solution.  This is 
done to help preserve the analytes, since oxamyl, 3-
hydroxycarbofuran, aldicarb sulfoxide, and carbaryl reportedly all 
can degrade rapidly in neutral or basic waters at room 
temperature.  A 50 mL portion of the sample is placed into a 50 mL 
volumetric flask and 5 5L of internal standard solution is added.  
Then 20 mL of this sample is  filtered, with only the last 5 mL of 
filtrate retained.  A 400 5L aliquot of this filtrate is injected 
into a HPLC where the analytes are separated on a 15 cm x 3.9 mm 
ID stainless steel column packed with reverse phase octadecylsilyl 
silica (C-18) stationary phase (Waters NovaPak C18 column or 
equivalent).  Following elution from the HPLC, the analytes are 
hydrolyzed with 0.05 N NaOH at 95 oC and the methyl amine formed 
during hydrolysis is reacted with o-phthalaldehyde and 2-
mercaptoethanol to form a highly fluorescent derivative which is 
detected by a fluorescence detector.   

EPA DRAFT METHOD #4 --  Determination of Pesticides in Ground 
                        Water by High Performance Liquid 
                        Chromatography with an Ultraviolet 
                        Detector

An approximate 1 L volume of water sample is fortified with a 
surrogate standard solution, the pH is adjusted to 7 with 
phosphate buffer, and 100 g of NaCl is added.  The sample is then 
extracted three times with 60 mL portions each of dichloromethane 
by shaking in a separatory funnel and the solvent portions 
combined.  An automated extraction method is permitted.  The 
extract is dried using anhydrous sodium sulfate, and concentrated 
and solvent exchanged to methanol using a K-D apparatus to a final 
extract volume of 5 mL.  An internal injection standard solution 
is added to the extract and a 10 5L aliquot of the extract is 
analyzed by HPLC with  ultraviolet (UV) detection at a 254 nm 
wavelength.  The primary HPLC column is a 25 cm x 4.6 mm ID 
stainless steel reverse phase C-18 column (DuPont Zorbax ODS or 
equivalent) with secondary confirmation accomplished using a  25 
cm x 4.6 mm ID silica column (DuPont Zorbax Silica or equivalent), 
if necessary. 

EPA DRAFT METHOD #6 --  Determination of Ethylene Thiourea (ETU) 
                        in Ground Water by Gas Chromatography with 
                        a Nitrogen-Phosphorus Detector

The ionic strength and pH of a 50 mL aliquot of the water sample 
is adjusted by adding 25 g potassium fluoride and 1.5 g ammonium 
chloride to the aliquot and shaking.  The aliquot is fortified 
with a surrogate standard solution, introduced onto a modified 
diatomaceous earth column and allowed to stand for 15 minutes.  
The column is then eluted with 400 mL of dichloromethane in 50-75 
mL portions, with the eluant collected into a K-D apparatus 
containing 5 mL of 1000 5g/mL dithiothreitol (a free radical 
scavenger) in ethyl acetate.  The eluant is concentrated to 5 mL 
using the Kuderna-Danish apparatus, and down to 1 mL using N2 
blowdown.  The extract is finally diluted to 5 mL with ethyl 
acetate and an internal injection standard is added.  The extract 
is analyzed by fused silica capillary column GC-NPD by injecting a 
2 5L aliquot of the extract onto each column.  The primary column 
is a 10 m x 0.25 mm ID column coated with polyethylene glycol (J & 
W Scientific DB-WAX column or equivalent).  The secondary 
confirmation column is a 5 m x 0.25 mm ID 14% cyanopropylphenyl 
methylpolysiloxane (DB-1701 type) column.  Both columns have a 
0.25 5m film thickness.

                        NWQL SCHEDULES

NWQL SCHEDULE 1389 -- Triazine Herbicides, Total Recoverable 
(O-3106-83)

An approximate 1 L volume water sample is fortified with a 
surrogate standard solution and transferred to a separatory funnel 
containing 5 g of NaCl.  The sample is adjusted to pH 7-9 with KOH 
or H2SO4 solution as necessary, and extracted with 75 mL of 
dichloromethane, and repeated with two 50 mL portions of 
dichloromethane.  The extracts are combined, dried with non-acid 
anhydrous sodium sulfate, transferred to a K-D apparatus 
containing 4 mL hexane and concentrated to 3-5 mL.  The extract is 
further concentrated to 1 mL and solvent exchanged to hexane using 
N2 blowdown, and then analyzed by dual fused silica capillary 
column GC-NPD using 2 5L injections of the extract per column.  An 
alumina column cleanup step can be included prior to GC analysis 
to eliminate interferents, if necessary.  The two GC columns are 
25 m x 0.25 mm ID columns coated with 0.25 5m film thicknesses of 
either methylpolysiloxane (Hewlett-Packard Ultra 1) or 5% phenyl 
methylpolysiloxane (Hewlett-Packard Ultra 2 or equivalent).

NWQL SCHEDULE 1319 --  Organophosphorus Insecticides, Total 
                       Recoverable    (O-3104-83)

An approximate 1 L volume water sample is fortified with a 
surrogate standard solution and extracted with three 50 mL 
portions of hexane.  The hexane portions are combined, dried with 
nonacid anhydrous sodium sulfate, concentrated to 3-5 mL using a 
K-D apparatus, and further reduced to 1 mL using N2 blowdown.  If 
schedule 1324 is also requested, the 1 mL extract is split in half 
with 0.5 mL carried though the schedule 1324 procedure outlined 
below for organochlorine insecticides, and the remaining 0.5 mL 
analyzed for organophosphorus insecticides by dual fused silica 
capillary column GC with a flame photometric detector using 2 5L 
injections of the extract per column.  If schedule 1324 is not 
requested, then the 1 mL extract is analyzed.  The two GC columns 
are 30 m x 0.25 mm ID columns coated with a 0.25 5m film thickness 
of either 5% phenyl methylpolysiloxane (J & W Scientific DB-5 
column or equivalent) or 14% cyanopropylphenyl methylpolysiloxane 
(J & W Scientific DB-1701 column or equivalent).

NWQL SCHEDULE 1324 --  Organochlorine Insecticides with Gross 
                       Polychlorinated Biphenyls (PCBs) and 
                       Polychlorinated Naphthalenes (PCNs), Total 
                       Recoverable  (O-3104-83)

The 0.5 mL split of the extract generated under the schedule 1319 
procedure above (or the entire 1 mL if schedule 1319 is not 
requested) is cleaned up by introducing the extract onto an 8.5% 
water deactivated alumina column, and eluting the column with 10 
mL hexane.  The hexane eluant is concentrated to 0.5 mL using N2 
blowdown, and analyzed by dual fused silica capillary column GC-
ECD using 2 5L injections of the extract per column.  The GC 
columns used are identical to schedule 1319.

NWQL SCHEDULE 1364 --  Polychlorinated Biphenyls as Aroclor 
                       Equivalents, Total Recoverable

This procedure is identical to schedule 1324, except that 
following the alumina column, the extract can optionally be 
further fractionated on a 3 percent water deactivated silica 
column prior to dual capillary column GC-ECD analysis.  The GC 
columns are those used for schedule 1324.  The silica column 
fractionation is included to separate the PCBs from other complex 
organochlorine mixtures, especially the components of technical 
Toxaphene and Chlordane.  

NWQL SCHEDULE 79 --  Chlorophenoxy Acid Herbicides with Dicamba 
                     and Picloram, Total Recoverable

An approximate 1 L volume water sample is fortified with a 
surrogate standard solution and transferred to a separatory funnel 
containing 200 g of NaCl.  The sample is acidified to pH 2 2 using 
H2SO4 solution and extracted with 100 mL diethyl ether, and 
repeated with two 50 mL portions of diethyl ether.  The extracts 
are combined into a K-D apparatus and 15 mL H2O plus 2 mL of 37% 
KOH are added to provide a pH 3 12.  The extract is then boiled on 
a steam bath to remove the diethyl ether, and then for another 90 
minutes to hydrolyze any chlorinated acid esters present.  The 
extract is transferred to a separatory funnel, washed with three 
10 mL portions of diethyl ether, acidified to pH 2 2 with 25% 
H2SO4, and extracted with three 10 mL portions of diethyl ether, 
which are combined and dried with acid-washed sodium sulfate.   
The extract is transferred to a K-D apparatus containing 0.5 mL 
benzene and concentrated to 1 mL.  Another 0.5 mL of benzene is 
added to the extract and it is further reduced to 0.5 mL using N2 
blowdown.  The chlorinated acids are converted to their methyl 
ester derivatives using a gaseous diazomethane derivatization 
procedure.  The extract is transferred to a 15% water-deactivated 
Florisil column, and eluted with 2 mL benzene (fraction 1, which 
contains all the chlorinated acid herbicides except picloram) 
followed by 2 mL of 20% diethyl ether in benzene (fraction 2, 
contains picloram).  Both fractions are analyzed separately by 
dual capillary column GC-ECD using 2 5L injections of the fraction 
per column.  The GC columns used are identical to schedule 1319.

NWQL SCHEDULE 1359 --  Carbamate Insecticides, Total Recoverable
                       (O-3106-83)

An approximate 1 L volume water sample is buffered to pH 7.5 using 
phosphate buffer, fortified with a surrogate standard solution, 
and extracted with 75 mL of dichloromethane, and repeated with two 
50 mL portions of dichloromethane.  The extracts are combined, 
dried with nonacid anhydrous sodium sulfate, transferred to a K-D 
apparatus and concentrated to 3-5 mL.  The extract is further 
concentrated to 1 mL and solvent exchanged to acetonitrile using 
N2 blowdown.  A 400 5L aliquot of the 1 mL extract is concentrated 
to dryness, reconstituted with 350 5L of 0.04% acetonitrile/water 
and analyzed by injecting 250 5L of this aliquot on a HPLC with 
photodiode array ultraviolet detection (UV).  The HPLC column is a 
25 cm x 2.1 mm ID reverse phase C-18 column (Beckmann Ultrasphere 
ODS).

                          REFERENCES

Code of Federal Regulations 40, Part 136, Appendix B, July 1, 1989 
- Definition and Procedure for the Determination of the Method 
Detection Limit - Revision 1.11.

EPA, 1988, Methods for the Determination of Organic Compounds in 
Drinking Water.  EPA/600-4-88-039.

Foreman, W. T., Zaugg, S.D., and Rogerson, P.F., 1990, Analytical 
interferences of HgCl2 preservative in environmental water 
samples:  1. Determination of semivolatile organic compounds 
isolated by liquid-liquid extraction  (under review).

Wershaw, R.L., Fishman, M.J., Grabbe, R.R., and Lowe, L.E., 1987, 
Methods for the Determination of Organic Substances in Water and 
Fluvial Sediments.  USGS Techniques of Water-Resources 
Investigations, Book 5 Chapter A3.