Use of EPA Analytical Methods
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PA’s 500 and 600 series methods are now widely used. It is clear that there are considerable overlaps among these methods in terms of both procedures and analytes. There are also considerable differences between these methods, some important and some trivial. These differences have proven troublesome for analytical labs that must faithfully execute these procedures. In response to these concerns, Section 518 of the Water Quality Act of 1987 directed EPA to study the availability and adequacy of field and laboratory test procedures and methods to support the provisions of the act. This study resulted in a report to Congress titled “Availability, Adequacy, and Comparability of Testing Procedures for the Analysis of Pollutants Established Under Section 304(h) of the Federal Water Pollution Control Act.” The report included the finding that “Improved coordination is needed in the Agency’s methods development program to avoid duplication in the development and standardization of test procedures and inconsistencies in quality assurance and quality control guidelines.” As a result, EPA asked Indiana University to consider the question “Is it possible to revise or eliminate some of the 500 and 600 series methods and effect a savings of time and money?” This and related questions were studied and seven recViews are insightful commentaries on timely enGmnmental topics, represent an author’s opinion, and do not necessarilyrepresentaposition of thesociety or editors. Contrasting views are invited.
ommendations were developed. A paper on these recommendations and the Process leading UP to them was published as a feature article in ESeT (1)and also presented at the 14th Annual EPA Conference on the Analysis of Pollutants in the Environment (Norfolk,VA, May 1991).
0013-936x192/0926-1285$03.00/0 0 1992 American Chemical Society
The recommendations are as follows: 1. Some existing 500 and 600 series methods should be revised and others dropped (I). The resulting methods could be used to determine about 340 compounds and mixtures. 2. Gas chromatography in any reEnviron. Sci. Technol.. Vol. 26, No. 7. 1992 1285
vised or new method should use capillary columns. This will provide sufficient resolution to distinguish analytes, especially when they are measured only by GC. 3. The format of official EPA methods should be standardized throughout the Agency, and the writing of revised methods should be modularized. Different methods should then incorporate the appropriate modules and thus promote uniformity among the methods and eliminate trivial but irksome differences. 4. A usage survey of EPA’s analytical methods should be conducted. This would aid in development of new methods, elimination of old methods, and revision of current methods. 5. Revised or n e w methods should have expiration dates, forcing EPA to either drop or recertify the method. Clearly, this would lead to the incorporation of the most up-to-date analytical technology. 6. The development of microextraction methods, using small volumes of sample a n d solvents, should be encouraged. These can be excellent, inexpensive screening tests, and also prevent pollution. 7.EPA should establish a system of training grants to increase the pool of environmental chemists.
602
624 625
608 601
Purgeable aromatics in municipal and industrial 124,395 wastewater by GC with phototonuation detection Purgeable organic compounds in municipal and 1 11,720 industrial wastewater by GCMS Besic, neuhal, and acidic or anic compounds in 86,104 municipal and industflal was%water by GCMS Organochlorine pesticides and PCBs in 80,193 mumcipel and industflal wassewater by GC with electron carwe (EC) detection Purgeable halawbons in municipal and 77.592 industrial wastewater by GC with electrolytic condwtivii detection
wastewater by
326
358 378 371 297
36,221
243
33,429
250
29,036
152
The survey In accordance with recommendation 4, Indiana University developed a questionnaire on usage of various EPA methods and sent it, along with a cover letter, to about 8000 individuals who were potential users of these methods. This questionnaire was mailed in late October 1991 and focused only on the 500 and 600 series methods. Each method was listed and responders were asked if their laboratory had performed the indicated method in the last three months and, if so, to estimate the number of samples that had been run with that method during that time. Indiana University received 633 responses, mostly from testing laboratories, which were tabulated by spreadsheet. The total number of laboratories using a given method and the total number of samples run with a given method were calculated. ReSUltS Table 1 ranks the methods by the number of analyses performed from August to October of 1991.The first number gives the total number of 1286 Environ. Sci. Technol.. Val. 26,No. ?,
1992
samples run with a particular method during the three-month survey period, and the second number is the number of laboratories doing those analyses. For example, during this period 124,395 samples were run using Method 602 for purgeable aromatic compounds: these samples were analyzed in 326 different laboratories. This averages to about 130 such analyses per month in each laboratory. At the other end of the scale, during the same three months, only 200 samples were analyzed using Method 513 for 2,3,7,8-tetrachlorodihenzo-p-dioxin; these samples were run in only 15 different laboratories. This is fewer than 5 such analyses per month in each laboratory.
It is important to keep in mind that these numbers are minimums, and it is entirely possible that labs actually performing these methods did not receive a questionnaire or, if they did, failed to respond. Conclusions The three most widely used methods account for 1.3 million samples per year; the number of samples run with all of the 500 and 600 series methods is about 3 million peryeor. These are remarkably high numbers and indicate the national importance of these EPA methods. Four methods account for more than half of this sample load: 602 (IS%), 624 (15%). 625 (ll%), and 608 (11%). There is a high correlation he-
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EPA
Dascrlption cd method
Nwnber
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Pur eaMe organic compounds in water by pacasd column GCMS Chlorinated hydrocarbons in munici I and industrialwastewater by GC wlth E&etection Acrolein and acryionitrile in muniapal and industrial wastewater by healed purge-and-trap GC with FID h-melhylcarbamoyloximesand h-methylcarbamatesin water by airect aqueous inlection HPLC with postcolumn oerivattzation Chlorination disinfectionbyproducts and chlorinated solvents in drinki water by microextraction and GC with2C detection PAHs in drinkkg water by liquid-solid extraction and HPLC PAHs in drinkin water by liquid-liquid extraction and ~ P L C Trihalomethanes in drinking water with GClMS and selected ion monitorino Organic compounds N n drinking water by Iiqud-solid extraction and capllary column GC,MS Phthalate esters in munici I and industrial wastewater by GC with E&eteclion Haloaceti acids in drinking water by liquidliquid extraction and GC with EC detection Glyphosate in drinking water by direct aqueous injection HPLC with postcolumn de
