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Occidental's Mel Rice discusses the study's findings at a press conference. By Pat Locke Occidental Chemical Co. gave its Lathrop fertilizer plant a clean bill of health Tuesday, an- nouncing conclusions from a $1.2 million groundwater and soil study which spanned the past nine months. Despite the optimistic outlook, ce, Occidental plant vice preb.—ent and general manager, said a pocket of the chemical DBCP was discovered in test wells at levels 900 times the maximum standard for drinking water. Occidental is already considering how to alleviate the problem, possibly by pumping the water through carbon filters to remove the pesticide. DBCP was manufactured at the Lathrop plant, but its use was banned in 1977 when it was discovered to possibly cause sterility and cancer in humans. The pesticide was used to control nematodes, tiny eel like crew.+.ores, which feed on the roots ■ vines and field crops. D__P has since been found in drinking water wells in the Lathrop area at levels exceeding the 1.0 part per billion level established as the state rnaximum. The recent study of 30 domestic wells revealed only onF with excessive levels of DBCP Occidental supplied bottle water, to the well owner, Rice said, as a "conservative" precaution. The concentrated pocket of DBCP was discovered by a serie of monitor wells drilled especially for the study. The wells are not used for drinking, however they are located less than 1,000 feet south of Louise Avenue. Rice said the study indicated that grounds water in the area is moving in north-northwest direction at rate 175-200 feet per year. Residentail developments ar > located north west of th Occidental plant, across Louis > Avenue. However, DBCP was not found in the residential area. DBCP levels are general l higher at shallower depths, Ric said. In the concentrated pock t of DBCP on the plant site, th pesticide was found at Lowe depths. He attributed the hig concentration of the pesticide t pumping in "the old days" whic .i drew water from the grouncl faster than it could be naturally} recharged. DBCP was just one of 0 pesticides monitored in the study, which included 500 samples of domestic well water and 200 samples of especially drilled monitoring wells. Only DBCP was found above the detectable limits of .10 part per billion. The study also showed relatively small amounts of radioactive materials in the Lathrop area, with no identifiable concentration patterns around the Occidental plant. Rice said the Occidental operations do produce some radioactive material through the production of gypsum and am- monia phosphate fertilizer. "Phosphate rock is slightly radioactive," Rice said. The majority of the radioactivity in the area, however, stems from naturally occuring uranium, he said. High radioactivity levels discovered in Nov. 1979 in several Lathrop wells, including the Lathrop School well prompted some residents to switch to bottled drinking water. The school chose to switch its drinking supply to a Lathrop County Water District well. Occidental also took 125 soil samples from the plant site and W,8 PW -6 This map shows where the DBCP pocket was found. surrounding areas. Except for an overflow ditch, • the western storage area and an old southwest gypsum pond, only low levels of chemicals were found, Rice said. The western storage area was excavated beginning in early May when company memos indicated the area was once used for a "cut and fill" dump site. The ex- cavation revealed some crushed five -gallon containers with no chemicals. Below that were nursery type bottles with some chemicals and some drums with industrial chemicals. The ex- cavated materials and surrounding soil were tran- sported to a class one hazardous waste dump site at the agreement of the state officials. The ditch, pond and former dump site which were excavated will be covered with a clay lining. In addition to organic chemicals such as DBCP, Occidental also tested for inorganic compounds. Only one well was found to have excessive sulfates, according to . Rice. Excessive chlorides were attributed to saltwater intrusion from ' the Delta. Neither sulfates nor chlorides were seen as a� health hazard. (Continued to Page A-12)