1,2-DIBROMO-3-CHLOROPROPANE (DBCP) AND ETHYLENE DIBROMIDE (EDB) IN WELL WATER IN THE FRESNO CLOVIS METROPOLITAN-AREA, CALIFORNIA/

Ground-water contamination with the pesticides 1,2 dibromo-3-chloropro pane (DBCP) and ethylene dibromide (EDB) affects Fresno/Clovis city in California. The spatial and temporal distribution of DBCP and EDB in public wells in Fresno/Clovis was examined, using mapping and time-ser ies analyses of chemical test results, during the time periods 1979-19 80 and 1992-1993. Health risks were estimated from mean concentrations , life-time cancer risks were estimated, and monitoring and control pr ograms were reviewed. Mean DBCP concentrations in selected wells decli ned from 0.56 ppb in 1979-1980 to 0.18 ppb in 1992-1993. Closure of we lls and wellhead filtration caused levels to be reduced further (i.e., to 0.06 ppb). Mean EDB concentrations declined from 0.25 ppb to 0.15 ppb during the same time periods. The estimated lifetime cancer risk f or DBCP was 1 excess death per 125 000 population in 1992-1993, but th is risk varied within the city. The risk for EDB was 1 excess death pe r 2.2 million. Recommendations were made for the modeling of pesticide movement in ground water and for epidemiological studies.