by Carol Potera
Excerpt: Although polychlorinated biphenyls (PCBs) were banned in the United States in 1977, they persist in the environment. These bioaccumulative chemicals can damage the immune, reproductive, endocrine, and nervous systems. When looking for environmental sources of PCBs, scientists generally measure dietary intake from fish, meat, and milk. However, older wood floor finishes that harbor PCBs may present an underestimated route for exposure, finds Ruthann Rudel, a toxicologist at the nonprofit Silent Spring Institute in Newton, Massachusetts.