Clarke, J.U., 1998, Evaluation of censored data methods to allow statistical comparisons among very small samples with below detection limit observations: Environmental Sciences and Technology, v. 32, no. 1, p. 177183.
Clark, M.J.R., and Whitfield, P.H., 1994, Conflicting perspectives about detection limits and about the censoring of environmental data: Water Resources Bulletin, v. 30, no. 6, p. 10631079.
Connor, B.F., Rose, D.L., Noriega, M.C., Murtagh, L.K., and Abney, S.R., 1998, Methods of analysis by the U.S. Geological Survey National Water Quality LaboratoryDetermination of 86 volatile organic compounds in water by gas chromatography/mass spectrometry, including detections less than reporting levels: U.S. Geological Survey OpenFile Report 97829, 78 p.
Eaton, A., 1993, Estimation of interlaboratory MDLs and RQLs: Environmental Lab, v. 5, p. 1014.
Gibbons, R.D., 1996, The problem with U.S. EPAs method detection limit: American Environmental Lab, February 1996, p. 410.
Gibbons, R.D., Coleman, D.E., and Maddalone, R.F., 1997a, An alternative minimum level definition for analytical quantification: Environmental Science and Technology, v. 31, p. 20712077.
______1997b, Response to comment on An alternative minimum level definition for analytical quantification: Environmental Science and Technology, v. 31, p. 37293731.
Gilliom, R.J., and Helsel, D.R., 1986, Estimation of distributional parameters for censored trace level water quality data, Part 1. Estimation techniques: Water Resources Research, v. 22, p. 135146.
Glaser, J.A., Foerst, D.L., McKee, G.D., Quave, S.A., and Budde, W.L., 1981, Trace analyses for wastewaters: Environmental Science and Technology, v.15, p. 14261435.
Hall, J.R., and Mills, S.A., III, 1997, Detection limits Where are we going?: Water Environment Laboratory Solutions, December 1997/January 1998, p. 1013.
Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in water resources: New York, Elsevier, 529 p.
Helsel, D.R., and Gilliom, R.J., 1986, Estimation of distributional parameters for censored trace level water quality data, Part 2. Verification and applications: Water Resources Research, v. 22, p. 147155.
Keith, L.H., 1992, Environmental sampling and analysis A practical guide: Chelsea, Mich., Lewis Publishers, p. 93119.
Koehn, J.W., and Zimmerman, A.G., 1990, How low can you really go?: Environmental Lab, v. 2, p. 3650.
Sandstrom, M.W., Wydoski, D.S., Schroeder, M.P., Zamboni, J.L., and Foreman, W.T., 1992, Methods of analysis by the U.S. Geological Survey National Water Quality LaboratoryDetermination of organonitrogen herbicides in water by solidphase extraction and capillarycolumn gas chromatography/mass spectrometry with selected-ion monitoring: U.S. Geological Survey Open-File Report 91519, 26 p.
Timme, P.J., 1995, National Water Quality Laboratory 1995 Services Catalog: U.S. Geological Survey OpenFile Report 95352, p. 92.
U.S. Environmental Protection Agency, 1984, Guidelines establishing test procedures for the analysis of pollutants (App. B, Part 209, Definition and procedures for the determination of the method detection limit): U.S. Code of Federal Regulations, Title 49, CFR 49(209):43430.
______1985, U.S. Code of Federal Regulations, Title 50: Washington, D.C., U.S. Government Printing Office, November 13, 1985, 46906.
______1993, Guidance on evaluation, resolution, and documentation of analytical problems associated with compliance monitoring: Washington, D.C., U.S. Government Printing Office, USEPA 821-B-93-001, June 1993.
______1997, Guidelines establishing test procedures for the analysis of pollutants (App. B, Part 136, Definition and procedures for the determination of the method detection limit): U.S. Code of Federal Regulations, Title 40, revised July 1, 1997, p. 265267.
U.S. Geological Survey, 1994, Description and guide for interpreting low-level data supplied by the NWQL for schedules 2001, 2010, 2050, and 2051: U.S. Geological Survey National Water Quality Laboratory Technical Memorandum 94.12, accessed May 13, 1999, at URL http://water.usgs.gov/admin/memo.
______1997, Changes in reporting levels and data qualifiers for selected pesticides and degradation products in schedules 2050 and 2051: U.S. Geological Survey National Water Quality Laboratory Technical Memorandum 98.03A, accessed May 13, 1999, at URL http://water.usgs.gov/admin/memo.
______1998, Reporting level changes for volatile organic compounds (schedules 2020/2021), inductively coupled plasma-atomic emission spectrometry (ICP-AES), ammonia plus organic nitrogen and phosphorus (micro-Kjeldahl) in water methods at the National Water Quality Laboratory Technical Memorandum 98.07, accessed May 13, 1999, at URL http://water.usgs.gov/admin/memo.
Werner, S.L., Burkhardt, M.R., and DeRusseau, S.N., 1996, Methods of analysis by the U.S. Geological Survey National Water Quality LaboratoryDetermination of pesticides in water by Carbopak-B solid-phase extraction and high-performance liquid chromatography: U.S. Geological Survey Open-File Report 96216, 42 p.
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: U.S. Geological Survey, Techniques of WaterResources Investigations, book 5, chap. A3, p. 7680.
Zaugg, S.D., Sandstrom, M.W., Smith, S.G., and Fehlberg, K.M., 1995, Methods of analysis by the U.S. Geological Survey National Water Quality LaboratoryDetermination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring: U.S. Geological Survey OpenFile Report 95181, 49 p.