Testing people for pollutants

In doing so, they've placed California in the vanguard of a national biomonitoring movement.

Biomonitoring involves looking for "pollution in people" -- testing bodily substances, usually blood and urine, for the presence of harmful substances, such as dioxins, polychlorinated biphenyls, or PCBs, and DDT. Traditionally, estimates of human exposure to toxic substances have been based on measurements of chemicals found in food, soil, air and water.

Because many chemicals accumulate in the fat cells of the breasts, the milk of new mothers -- particularly during the first few weeks of nursing -- contains a high concentration of chemicals. Testing the milk could offer insight into any possible connection between pollution and disease.

"Biomonitoring is telling us what's in our bodies and are [the levels of those toxic substances] going up or down -- are there things we need to worry about?" says Kim Hooper, a state scientist who is co-directing the breast-milk biomonitoring study in Torrance, the Central Valley and Marin County. That study, of 120 women, is conducted by the Environmental Protection Agency and is already underway.

Activists in the field of breast cancer, frustrated that genetics and diet only partly explain the dramatic rise in rates of the disease in the past 50 years, are pushing to expand biomonitoring even further. They want a statewide program that will focus on possible causes of breast cancer as well as other diseases.

Legislation sponsored by the Breast Cancer Fund, a nonprofit health advocacy group, would -- among other things -- make California the first state in the nation to regularly test mothers' milk for dangerous chemicals.

"It became very clear to us that what is not being addressed is the unexplained risk factors in breast cancer," says Jeanne Rizzo, executive director of the group. "We saw more and more science connecting synthetic chemicals with breast cancer."