Office of Water Quality Technical Memorandum 2001.05

Subject: Preferred Parameter Codes for Indicator Bacteria Methods

The large number of parameter codes established over the years for storing microbiological determinations in STORET and NWIS has led to some confusion as to which is the most appropriate code to use with each method. This confusion is due primarily to incomplete or misleading descriptions listed with the codes and duplication where two codes represent the same method.

The purpose of this memo is to communicate some newly updated descriptions for some indicator bacteria parameter codes and indicate which of these codes is preferred for the Water Resources Division. New descriptions were established to better represent the analysis and to obtain a consistent format. The old parameter description for all codes that have been updated is listed in brackets for reference. The codes listed first under each category indicate the preferred methods for water analysis and are the ones listed on the newly revised ground and surface water-quality field forms. Additional codes listed are for similar but not preferred methods, for proprietary methods (Colilert), or for methods testing sediments.

Projects may have bacteria data stored in NWIS under parameter codes different from the ones listed as preferred in this memorandum. Historical data do not need to be changed but all new data as of March 1, 2001, should follow guidance from this memorandum. Districts should, at their discretion, update any data that may have been stored erroneously due to confusion with the older misleading parameter descriptions.

Questions about the information in this memorandum should be directed to Donna Francy (dsfrancy) in the Ohio District or Stephen Sorenson (sorenson) in the Office of Water Quality.

TOTAL COLIFORM:

31501, Total coliform, mENDO MF method, water, colonies/100 ml [coliform, membrane filter immediate mENDO medium (colonies/100 ml)]—This parameter code is the proper code for the membrane filter, mENDO agar method (Britton and Greeson, 1987, p. 13-16).

31504, coliform total immed. mem. fil (col./100mL) —This parameter code description has the method missing and is not recommended for use with any new data.

50569, Total coliform, Colilert Quantitray method, water, mpn/100 ml [total coliform, ONPG-MUG, autoanalysis, Colilert system, water, unfiltered, most probable number per 100 milliliters]--This is the Colilert Quantitray method (Idexx Laboratories, Westbrook, Maine). Code 90908 is a temporary code for this same analysis but should not be used with any new data.

90900, Total coliform, MI MF method, water, colonies/100 ml [total coliform, water, unfiltered, MF, MI agar, 35 degrees Celsius, colonies per 100 milliliters]—This is the MI agar method and allows the simultaneous enumeration of total coliforms and Escherichia coli (U.S. Environmental Protection Agency, 2000a). It is recommended for use in analyzing ground-water samples.

FECAL COLIFORM:

31625, Fecal coliform, mFC MF method, water, colonies/100 ml [Fecal coliform, .7 um-MF (col./100 mL)]—This is the mFC agar method (Britton and Greeson, 1987, p. 37-40). Parameter [dsf1] code 31625 was established when the 0.7 micron filter was recommended for the mFC method.

31616, Coliform, fecal, membrane filter m-FC media at 44.5 deg. C (colonies/100 ml)—This is the mFC agar method and is identical to parameter code 31625 except that it uses a 0.45 micron filter. The use of the 0.45 micron filter is not recommended for fecal coliform analysis but this parameter code was used extensively in the past.

50469, Fecal coliform, mFC MF method, sediment/bed material, colonies/gm (dry weight) [fecal coliform, sediment, bed material, MFC agar, 44.5 deg C, 24 hr, dry weight, col/gm]—This is the mFC agar method for sediment.

ESCHERICHIA COLI (E. COLI):

31633, E. coli, mTEC MF method, water, colonies/100 ml [E. coli, water, whole, total, thermotol, MF, m-TEC, in-situ, urease, (col/100ml)]—This is the mTEC agar method (U.S. Environmental Protection Agency, 1986 and 2000b) for water and is widely used for monitoring recreational and ambient surface waters.

50278, E. coli, NA-MUG MF medium, water, colonies/100 ml [E. coli, water, filtered, MF, 0.7 u, Nutrient agar + MUG, 4 hours, 35 degrees C, colonies]—This is the NA-MUG method for water (U.S. Environmental Protection Agency, 1991), to be used as a secondary incubation with mENDO medium (code 31501) for total coliform. This method is recommended for use in analyzing ground-water samples.

50466[dsf2] , E. coli, mTEC MF method, sediment/bed material, colonies/gm (dry weight) [E. coli, MF, m-TEC agar, urease, bed material, dry weight, colonies/gram]— This is the mTEC agar method for sediment.

50467, E. coli, Colilert Quantitray method, sediment/bed material, mpn/gm (dry weight) [E. coli, ONPG-MUG, auto analysis, Colilert system, bed material, dry weight, colonies/gram]--This is the Colilert Quantitray method for sediment.

50468, E. coli, Colilert Quantitray method, water, mpn/100 ml [E. coli, ONPG-MUG, auto analysis, Colilert system, water, unfiltered, colonies/100]--This is the Colilert Quantitray method for water.

90901, E. coli, MI MF agar, water, colonies/100 ml [E. coli, water, unfiltered, MF, MI agar, 35 degrees Celsius, colonies per 100 milliliters]--This is the MI agar method (U.S. Environmental Protection Agency, 2000a) for E. coli in water.

90902, E. coli, modified mTEC MF method, water, colonies/100 ml [E. coli, water, unfiltered, MF, modified m-Tec agar, colonies per 100 milliliters]--This is the modified mTEC method for water method (U.S. Environmental Protection Agency, 2000b) and is a one-step alternative to the standard mTEC method (31633) for monitoring recreational and ambient surface waters.

FECAL STREPTOCOCCI:

31673, Fecal Streptococci, KF streptococcus MF method, water, colonies/100 ml [Streptococci, fecal, membrane filter, KF agar (colonies/100 ml)]—This is the KF streptococcus agar method for water (Britton and Greeson, 1987, p. 47-50).

ENTEROCOCCI:

31649, Enterococci, mE MF method, water, colonies/100 ml [Entercocci, mE, membrane filter, water, whole, total (colonies/100 ml)]—This is a 48-hour, two-step test for enterococci using the mE agar method (U.S. Environmental Protection Agency, 1986).

90909, Enterococci, mEI MF method, water, colonies/100 ml [Enterococci, mEI, biota, water, filtered, membrane filter, 24-hour incubation, onestep method, colonies per 100 ml]—This is the 24-hour, one-step test for enterococci using mEI agar (U. S. Environmental Protection Agency, 1997 and 2000b).

Either method for enterococci may be used with equal preference.

CLOSTRIDIUM PERFRINGENS:

90915, Clostridium perfringens, mCP MF method, water, colonies/100 ml [Clostridium perfringens, MF, mCP agar, Amm. Hydrox., 44.5 deg C, water, colonies/100 ml]—The mCP agar method (U.S. Environmental Protection Agency, 1996) is done in the laboratory.

REFERENCES:

Britton, L.J., and Greeson, P.E., eds., 1987, Methods for collection and analysis of aquatic biological and microbiological samples: U.S. Geological Survey Techniques of Water-Resources Investigations, book 5, chap. A4, variously paginated.

U.S. Environmental Protection Agency, 1986, Test method for Escherichia coli and enterococci in water by the membrane-filter procedure: Cincinnati, Ohio, EPA 600/4-85/076, 24 p.

U.S. Environmental Protection Agency, 1991, Test methods for Escherichia coli in drinking water—Test Method 1105: Cincinnati, EPA/600/4-91/016, 2 p.

U.S. Environmental Protection Agency, 1996, EPA Information Collection Rule microbial laboratory manual: Washington, D.C., EPA/600/R-95/178, section XI.

U.S. Environmental Protection Agency, 1997, Method 1600—Membrane filter test method for enterococci in water: Washington, D.C., EPA/821/R-97/004, May 1997.

U.S. Environmental Protection Agency, 2000a, Membrane filter method for the simultaneous detection of total coliforms and Escherichia coli in drinking water: Cincinnati, Ohio, EPA 600-R-00-013, 20 p.

U.S. Environmental Protection Agency, 2000b, Improved enumeration methods for the recreational water quality indicators: Enterococci and Escherichia coli: Washington, D.C., EPA/821/R-97/004, March 2000.

Janice R. Ward

Acting Chief, Office of Quality

This memorandum does not supersede any other Office of Water Quality Technical Memorandum.

Distribution: All WRD Employees