Contaminated Military Bases:
- Marine Corps Logistics Base Barstow
- El Toro Marine Corps Air Station (decommissioned)
- Mather Air Force Base
- McClellan Air Force Base
- March Air Force Base
- Norton Air Force Base
- Camp Pendleton Marine Corps Base
24 Bases with reported TCE water contamination
(Source: Agency for Toxic Substances and Disease Registry)
Lake City Army Ammunition Plant
Independence, MORead more about this article..
On-Site Groundwater Contamination
Results of 1999 quarterly and annual monitoring of drinking water from LCAAP's water supply plant (treated water prior to distribution) showed that vinyl chloride (0.9 parts per billion [ppb]) slightly exceeded ATSDR's health-based CV of 0.7 ppb. Four other chemicals exceeding CVs, bromodichloromethane (BDCM) (6.2 ppb), bromoform (5.0 ppb), bromomethane (69.6 ppb), and dibromochloromethane (CDBM) (9.3 ppb), were present in the finished water (Continental 1999a; 1999b). BDCM, bromoform, bromomethane, and CDBM are not chemicals associated with the routine operations at LCAAP. These chemicals are common by-products of chlorination. Chlorine is added to drinking water to kill disease-causing organisms (ATSDR 1989, 1990, 1992).
TCE and other VOCs have been detected in several of the plant's 13 drinking water supply wells prior to being processed by air strippers. During 1998-1999, TCE (34 ppb) was detected in supply well 17-AA (located within Area 12) above its CV. One sample at supply well 17-K (Area 22) and three samples at supply well 17-P (Area 14) contained vinyl chloride (8 ppb) above its CV. One sample collected in November 1998, at supply well 17-JJ (located near the center of the plant), contained tetrachloroethylene (PCE) (1.7 ppb), slightly above its CV (Dames & Moore 1999; Dames & Moore 2000).
Results of samples collected from 1990 to 1997 indicate that three of the 13 active water supply wells (17-AA, 17-K, and 17-P) contained levels of contaminants above CVs. TCE (52 ppb) was detected above its CV in well 17-AA and the levels appeared to be relatively stable from 1990 through 1997. Water from this supply well was not drawn from extensively in the past because of its high mineral content (F.J. Abshier, Olin Corporation, Winchester Division, personal communication, October 26, 1999). Vinyl chloride (8 ppb) was detected above its CV in wells 17-K and 17-P. Vinyl chloride was detected only once in well 17-K (Dames & Moore 1999). One supply well (17-FF) was converted to a water extraction and recovery well in 1998 and is currently being used to remove VOCs. Samples collected from this well, prior to its conversion, contained 1,2-dichloroethylene (1,2-DCE) (380 ppb) and vinyl chloride (270 ppb) (Dames & Moore 1999).
On-site - It is possible that prior to air strippers being installed at the plant, individuals may have consumed water from supply wells that contained levels of VOCs above ATSDR's health-based CVs. Past water sampling data have detected VOCs in excess of CVs in four water supply wells. Vinyl chloride has occasionally been detected at levels slightly above its CV in two supply wells (17-K and 17-P) and TCE has been consistently detected above its CV in one supply well (17-AA). Recovery well 17-FF was used as a supply well prior to 1998 and contained 1,2-DCE and vinyl chloride above their CVs.
When estimating the health significance of an exposure pathway, ATSDR estimates exposure doses and compares the values to standard health guidelines. In calculating human exposure doses, ATSDR made very conservative assumptions about the frequency and duration of exposure. ATSDR also assumed that LCAAP workers and on-site residents would be exposed to the maximum contaminant concentrations detected. These assumptions are often necessary because ATSDR does not know with certainty when contaminants first reached supply wells or how much contamination was present at the time water was being consumed from these wells. These assumptions likely overestimate actual exposure because workers are not likely to obtain most of their drinking water from LCAAP and the small number of individuals who have lived in the on-site housing area generally only reside there for a short period of time. Moreover, individuals at LCAAP are not likely to be exposed to these maximum concentrations because water from all supply wells is blended and stored in a large holding tank. The methods and assumptions used to estimate exposures and evaluate potential health effects are described in greater detail in Appendix C.
Since no individual well at LCAAP ever supplies all the drinking water for LCAAP and no one person drinks exclusively from one supply well at the maximum contaminant concentration, ATSDR concluded that past exposure to the LCAAP drinking water supply poses no public health hazard.
Off-site - Results of off-site groundwater monitoring tests and residential private well monitoring indicate that some VOCs, explosives, and metals, mostly at low levels, have migrated beyond the plant's perimeter in the north central portion of the plant, which includes the Area 18 OU and the Northeast Corner OU. A few contaminants, benzene, TCE, and 1,1-DCE, were detected at levels slightly above their CVs.
ATSDR evaluated exposures to private well water by off-site residents using the same conservative approach described above (see Appendix C). Based on this evaluation, ATSDR concluded that drinking water from these private wells does not pose a past health hazard because contaminant concentrations are too low to cause adverse health effects.