Study links home pesticides and cancer
A study recently published in the American Journal of Public Health has found elevated rates of cancer in children exposed to pesticides in their homes and gardens.
The study by researchers in North Carolina examined the association between childhood cancer and home pesticide use in a case-control study of children under 15 years of age. The study found a four-fold increase in the risk of soft-tissue sarcoma in children whose yards were treated with pesticides, and a link between use of pest strips containing dichlorvos and the incidence of childhood leukemia.
Researchers interviewed parents of 252 children diagnosed with cancer between 1976 and 1983 in the Denver, Colorado, area, as well as 222 control subjects, about their use of home pest extermination, yard treatment and pest strips.
Respondents were asked details regarding extermination and pesticide use for each residence in which they lived for six months or more, beginning with the time of the mother's pregnancy. Researchers point out, however, that a primary weakness of this and other studies is the inability to measure accurately any pesticide exposures.
Analysis of data gathered from these interviews found evidence of an association between home extermination and lymphomas, but not other cancers. In cases examined for the study, pesticides most likely used for home pest control were chlordane, heptachlor, diazinon and chlorpyrifos (Dursban).
Chlordane and heptachlor are included on Pesticide Action Network (PAN) International's "dirty dozen" list of pesticides. In 1988, Velsicol Chemical Co., the US registrant, voluntarily cancelled products containing these pesticides in the US. The only commercial use of heptachlor products still permitted in the US is for fire ant control in underground power transformers. However, both pesticides are still manufactured for export.
Diazinon use in the US exceeds 3.6 million kg, with approximately 75 million applications made to homes, yards and gardens. Chlorpyrifos is the most widely used insecticide in the US, both in crop production and in non-agricultural applications. More than 200 million chlorpyrifos applications are made annually in US homes, lawns and gardens.
The study found relatively strong associations between use of pest strips containing dichlorvos and leukemia. Dichlorvos is a known carcinogen in animals, and previous studies have linked the insecticide to leukemia in adult men. Pest strips present an exceptional health risk because they emit a continuous vapour of dichlorvos into the household air.
The US manufacturer of dichlorvos, Amvac Chemical Corporation, has recently requested voluntary cancellation of some indoor home uses. However, pest strips, total release foggers and crack and crevice treatments would still be allowed. Several outdoor uses of dichlorvos including food and non-food greenhouses, food handling and processing establishments, buses and airplanes, will also be voluntarily cancelled by the manufacturer. According to an EPA official, the voluntary cancellation request is not "risk related".
[From the US Pesticide Action Network.]