2 SILENT SPRING REVIEW
WINTER 2002 3
Since 1957, when Patti Page first sang about the sand dunes and salty air of old Cape Cod, Jane Chase has lived at the same address on the elbow of the Cape. Her white clapboard house overlooks a marsh, where great blue herons feed, sometimes year-round. From her deck, she can hear the chirping of ospreys as she watches waves lapping against the nearby shores of Nantucket Sound.
Despite its tranquillity, Chase fears her beloved landscape may not be as idyllic as it seems. In 1993, she learned that women on Cape Cod have been disproportionately affected by breast cancer, which led her to wonder about her own diagnosis, two years earlier. Like many other Cape women with the disease, she had no family history of breast cancer. Could she have been exposed to pesticides through spraying for mosquitoes
on the marsh decades ago, or through another, as yet unidentified environmental source?
In 1994, Chase’s questions led her to begin volunteering with Silent Spring Institute, which had just launched the Cape Cod Breast Cancer and Environment Study. “The Institute’s scientists are working with those of us in the community to investigate possible relationships between environmental pollution and breast cancer,” Chase says. “Our goal is to identify preventable causes of the disease not just for Cape residents, but for everyone.”
Cape Study researchers have since undertaken many stages of research, from tracking pesticide spraying on golf courses to interviewing women about their gardening habits. Central to the investigators’ work is their geographic information system (GIS), a sophisticated computer mapping database that now represents the most comprehensive source of information about health and the environment on Cape Cod.
The GIS allows researchers to overlay environmental data from many sources, such as the area maps that they have painstakingly reconstructed to document pesticide applications made in the past 50 years. Maps of drinking water supply wells have been overlaid onto historical land use maps to identify potential sources of contamination. And, with land use information dating back to the 1950s, the researchers can assess how transformations to the land—from forests to farms to residences—may have contributed to chemical exposures in humans.
In the most recent phase of the study, the research team interviewed more than
Researchers are combining information about historical land use on Cape Cod with the location of a woman’s home to determine her exposure to compounds being studied for breast cancer. She would likely have been exposed to pesticides if her home was built, for example, on old farmland or downwind from a cranberry bog.
Eleven communities on Cape Cod have
breast cancer rates that are at least 15
percent higher than those of the rest of
Massachusetts. Pesticide use is one
factor Silent Spring Institute scientists
are analyzing closely. Historically,
pesticide use on Cape Cod may have
been unusually high because of the
large number of cranberry bogs, such as
the one pictured here; wetlands
harboring mosquitoes; and wooded
areas susceptible to gypsy moths and
2,100 Cape Cod women—both those with and without breast cancer—about personal health, exercise habits, and household product use. “We asked women about their use of pesticides and certain products that may contain estrogen mimics,” says Julia Brody, PhD, executive director of the Institute. “Because we know that a woman’s exposure to her own estrogen increases breast cancer risk, researchers have been asking whether estrogen mimics in household products and environmental pollutants can also increase risk. The Cape Study will help answer that question.”
The estrogen-like compounds the scientists are investigating can be found in everyday products, including pesticides, detergents, plastics, and cosmetics. “Some of the compounds we are studying are also a focus of research on prostate cancer, asthma, and reproductive health problems,” Brody says. “We hope the data we collect will help to identify causes not only of breast cancer but also a variety of health problems.”
As part of the interview phase of the study, women provided the addresses of all the houses on the Cape in which they had lived since 1948. Working with a GIS consulting firm, Applied Geographics, Inc., Institute researchers created a “spatial proximity tool” aimed at evaluating the likely exposure of each residence to potentially hazardous chemicals. The considerations are numerous: a nearby forest may have acted as a buffer against previous pesticide sprayings, for example, or a house may have been built on the site of a former farm, which had undergone repeated applications of chemicals that can persist in soil for decades. With the GIS, the investigators are now able to recreate for each woman a history of possible environmental exposures as she has moved from house to house.
With the interviews now completed, Institute researchers are turning their attention to linking the women’s personal details with environmental data in the GIS. In addition, from the homes of 120 of the women interviewed, the scientists are taking air and dust samples that will be analyzed for more than 80 chemicals.
Throughout their work, the researchers have made much of the information in the GIS available through an atlas on the Institute’s website. With information about breast cancer incidence, historical pesticide use, drinking water quality, census data, and land use, the atlas serves as a source of information about the Cape environment and as a resource for those who want to explore possible effects of the environment on health.
The investigators hope that the overlays of information they have entered into the GIS will help them detect any associations between areas of likely environmental impact and patterns of breast cancer incidence. For Jane Chase, who has four children and nine grandchildren living on the Cape, the study results cannot come too soon. “Cancer has changed a lot in my life and in how I think about things,” she says. “This study gives me hope that we don’t have to accept breast cancer as a fact of life. It’s important that we keep pushing forward to find the answers so that we can protect future generations.” ■
|Measuring Indoor Risks to Health|
How can we determine what chemicals we are exposed to indoors, where most of us spend much of our time? Silent Spring Institute researchers have developed methods to test for more than 80 chemicals in the air and dust in homes and businesses. These chemicals were targeted because they may have implications for breast cancer and other health concerns.
The pilot study, conducted by
Ruthann Rudel, a senior scientist at
Silent Spring Institute, and colleagues at