FIELD DOCUMENTS AND WORK PLANS 2000-2003

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c Cancer SurveillaSe Program S 12800 L Street, #440 P Sacramento, CA 95816-5600 September 21, 2000 Donna Heran,Director Environmental Health Division 304 E. Weber Ave., Third Fl. fig Un;� Stockton, CA 95202 0 E)-4qA Dear Ms. Heran; This letter is in response to your request for information about cancer incidence in the vicinity of the Marley Cooling Tower in Stockton. The Cancer Surveillance Program, as Region 3 of the California Cancer Registry, collects information about cancer diagnosed among the approximately 2.9 million residents of thirteen counties in the Sacramento area. One of the uses of cancer registry data is to evaluate incidence of cancer, and to assess whether the number of new cancer cases is greater than the number that would be expected for a population. The census tract is the geographic division for which we have detailed 1990 population data and is the unit that we usually use to assess cancer incidence. The geographic area around the plant(according to the map you supplied)is contained in four census tracts (2600, 2701, 2702, and 3700)that include the area north of Highway 4 and east of Highway 99. These census tracts had a combined population in 1990 of approximately 12,000 people, although the population is likely to have changed since then. Based on my calculations using the 1990 age, race and sex-specific population figures and the corresponding regional cancer rates, the number of cases of cancer that would be expected in this neighborhood over a ten-year period is 484. According to registry records, the number of cases that were diagnosed among residents of this census tract in the ten-year period 1988 through 1997 was 490, almost exactly the number that would be expected. Similar to the rest of the state, the most frequently diagnosed cancers among residents were lung, breast, colorectal and prostate cancer. I also did not observe any excess incidence of the cancers that you suggested might be expected to be elevated with exposure to hexavalent chrome in drinking water. I calculated expected versus observed numbers for cancers of the esophagus, stomach, kidney and renal pelvis, and liver. For none of these cancers was the observed number of cases during the ten year period significantly higher than the number expected. I hope this information is helpful. Let me know if I can be of further assistance. Sincerel Rosemary Donalds Cress, DrPH Epidemiologist cc: Karen Furst, MD, MPH, San Joaquin County Department of Health Dr. William Wright,California Dept. of Health Services, Cancer Surveillance Section Cynthia Creech, Cancer Surveillance Program Region 3 of the California Cancer Registry Telephone: 916-454-6522 FAX: 916.454-6523