Table 1. Availability and Characteristics of Data on MTBE in Drinking Water Used in The

Table 1. Availability and characteristics of data on MTBE in drinking water used in the 12-State study1 [CWSs, community water systems; MTBE, methyl tert-butyl ether; g/L, micrograms per liter; NA, not applicable; mg/L, milligrams per liter]

State Number of Number of Number Period Analytical reporting levels Source and status Data processing randomly randomly of of used by State lab(s) of MTBE data performed by USGS selected selected MTBE record (g/L) CWSs in CWSs with analyses study design1 MTBE data

Connecticut 120 120 507 2/19/93 - 10, 5.0, 2.0, 1.0, 0.5 and 0.2 Connecticut Department of Public files scanned and/or typed into 12/31/97 Health, Water Supplies Section; database MTBE analyzed by State and private labs, data on paper files Delaware 46 0 0 NA NA Delaware Health and Social Services, Division of Public Health, Office of Drinking Water; no MTBE available Maine 80 55 122 2/25/97 - 1.0 Maine Department of Human Services,MTBE populated as <1.0 g/L in all 7/21/98 Division of Health Engineering; post Feb. 1997 samples without MTBE analyzed in samples run by detects DOHS lab since Feb. 1997, reported only when detected Maryland 101 101 456 1/3/95 - 0.5 Maryland Department of the Envi- identified MTBE data as MDE 1/7/98 ronment, Water Supply Protection parameter ‘VOC2251” based on Program; MTBE analyzed in all USEPA parameter code 2251 for samples since Jan. 1995 MTBE Massachusetts 105 75 270 1/5/93 - 5.0, 2.0, 1.0, and 0.5 Massachusetts Department of Envi- MTBE populated when not detected 12/7/98 ronmental Protection, Division of by review of paper files Water Supply; MTBE analysis optional and reported only when detected New Hampshire 134 130 387 1/3/95 - 0.5 New Hampshire Department of MDL populated as <0.5 g/L for all 6/30/98 Environmental Services, Water sample with “BDL” code for non Supply Engineering Bureau; MTBE detects analyzed by DES lab since Jan. 1995 New Jersey 122 65 510 2/5/97 - 2.0, 0.54, 0.5, 0.36, 0.3, 0.25, 0.24, New Jersey Department of Environ- identified MTBE data as NJDEP 12/8/98 0.12, and 0.1 mental Protection, Division of code (AS_CONID = 2251) based Water Resources, Bureau of Safe on USEPA parameter code 2251 Drinking Water; MTBE analyzed for MTBE most samples since may 1997

New York 538 241 1,839 1/5/95 - 10, 5.0, 1.0, and 0.5 New York Department of Health, MTBE data listed under 6 parameter 12/15/98 Bureau of Public Water Supply name spellings combined Protection; MTBE analysis required in some counties, State, county, and private labs Pennsylvania 443 0 0 NA NA Pennsylvania Department of Envi- ronmental Protection, Division of Drinking Water Management; no MTBE data available Rhode Island 30 30 511 1/5/93 - 1.0 and 0.5 Rhode Island Department of Health; no processing required 7/9/98 MTBE analysis by State lab since 1991 Vermont 87 75 184 1/4/95 - 2.0 and 1.0 Vermont Department of Environ- MTBE populated when not detected 12/24/97 mental Conservation, Water Supply by review of paper files; Division; MTBE reported only when converted from mg/L to g/L detected Virginia 304 302 724 1/21/97 - 0.5 Virginia Department of Health, Office MTBE populated as <0.5 g/L for 2/24/98 of Water Programs; MTBE analyzed all samples with non detects since by State lab in all samples since April 1997 April 1997 but not reported unless detected Total 2,110 1,194 5,510 1/5/93 - 10, 5.0, 2.0, 1.0, 0.54, 0.5, 0.36, 12/15/98 0.3, 0.25, 0.24, 0.2, 0.12, and 0.1

1 the following U.S. Geological Survey reports, available at http://sd.water.usgs.gov/nawqa/vocns or clickable below, document the design, data analysis, and findings of the 12-State retrospective assessment of MTBE in drinking water:

Grady, S.J. and Casey, G.D., 1999, A plan for assessing the occurrence and distribution of methyl tert butyl ether and other volatile organic compounds in drinking water and ambient ground water in the Northeast and Mid-Atlantic Regions of the Unites States: U.S. Geological Survey Open-File Report 99-207, 36 p. (pdf version)

Grady, S.J., and Casey, G.D., 2001, Occurrence and distribution of methyl tert-butyl ether and other volatile organic compounds in drinking water in the Northeast and Mid-Atlantic regions of the United States, 1993-98: U.S. Geological Survey Water-Resources Investigations Report 00-4228, 123 p. (pdf version)

Moran, Michael, Grady, Stephen, and Zogorski, John, 2001, Occurrence and distribution of volatile organic compounds in drinking water supplied by community water systems in the Northeast and Mid-Atlantic regions of the United States, 1993-98: U.S. Geological Survey Fact Sheet 089-01 4p. (pdf version)

Squillace P.J., and Moran, M.J., 2000, Estimating the likelihood of MTBE occurrence in drinking water supplied by ground-water sources in the Northeast and Mid-Atlantic regions of the United States: U.S. Geological Survey Open-File Report 00-343, 10 p. (pdf version)