Daily News Archive
From March 5, 2002

New Computer Tool Tracks Pesticide Exposure Through History

The Spatial Proximity Tool, a new computer technology developed as a part of Silent Spring Institute's Cape Cod Breast Cancer and Environment Study, links individual addresses with historical environmental data. Announced in a paper published by the Journal of Exposure Analysis and Environmental Epidemiology, the software can determine distance and direction from areas where a pesticide was used and a pesticide's persistence in the environment.

This exposure assessment tool can help women who have been diagnosed with breast cancer, but didn't know they were at risk. Jane Chase, the first in her family to be diagnosed with breast cancer, is concerned. "I've lived in my home since 1957. It's next to a marsh that could have been sprayed for mosquitoes. But I have no idea what pesticides were used or what long-term effects they may have."

The Silent Spring Institute's Cape Cod Breast Cancer and Environment Study is investigating the relationship between the environment and breast cancer on Cape Cod, MA, a region with a history of higher incidence of the disease. Information from interviews with 2,100 women participating in this study is combined with data from the Spatial Proximity Tool to provide a more precise picture of women's pesticide exposures.

Researchers from Silent Spring Institute conducted extensive fieldwork, which yielded information about historical pesticide practices and maps used by pilots for aerial spraying programs dating back to the 1950s. The data is integrated using a computer mapping technology, geographic information system (GIS), which combines and layers multiple data sources. Institute researchers estimated the relative intensities of pesticide exposures between 1948 and 1995 at each of the participants' Cape Cod residences, and found that, during these years, more than two dozen chemicals, including DDT, dieldrin, and Sevin® were applied on Cape Cod.

Dr. Julia G. Brody, executive director of Silent Spring Institute and lead author on the study, describes what this tool could mean to concerned residents and to researchers in the field of epidemiology. "The ability to efficiently capture a woman's pesticide exposures dating back to earlier years is key to learning how pollutants affect cancer risk. Our ultimate goal is to discover risk factors we can change. We owe it to our daughters to find ways to bring down breast cancer risk."

To find out more about the Spatial Proximity Tool, see www.silentspring.org.