Word: pcbs
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While the consensus favors a fat connection, other explanations haven't been ruled out. One is chemical pollution in the food chain--specifically, DDE, a breakdown product of the pesticide DDT, and PCBs, once used as flame retardants in electrical equipment. Both chemicals are plausible suspects because they mimic hormones that play a key role in the development of the reproductive system. Beyond that, says Dr. Walter Rogan, an epidemiologist at the National Institute of Environmental Health Sciences in Research Triangle Park, N.C., both chemicals are ubiquitous in the environment, and they persist in the body for years after exposure...
...that reason, he chose PCBs and DDE for one of the very few large, long-term studies of chemical exposure and puberty in humans. Rogan and his colleagues began with some 600 pregnant women, measuring concentrations of the chemicals in their bodies. When their babies were born, the researchers then measured levels in the mothers' breast milk. Finally, the team monitored the children as they grew and entered puberty...
...most prominent effect, reported last spring in the Journal of Pediatrics, was that boys exposed to DDE and girls exposed to PCBs were heavier than their unexposed peers at age 14. The study also noted an intriguing fact: girls with high prenatal PCB exposure tended to hit the first stages of puberty a bit earlier than others. Rogan stresses that the numbers were too low to be statistically significant. "If there is an effect of environmental chemicals on puberty," he says, "it's pretty small, because we studied these kids in detail over a long period of time...
Could other substances besides PCBs and DDE influence sexual development? Perhaps, Rogan says. But few compounds are as persistent and pervasive. Hormones given to livestock, for instance--another frequently invoked possibility--break down very quickly in the body. "I have not studied the effects of hormones in beef or dairy cattle," Rogan says. "It's not something I'm running out to study either...
...enemy. Silt running off dirt roads and clear-cut forest land ruins coral reefs and U.S. salmon rivers. Pesticides and other toxics sprayed into the air and washed into rivers find the ocean. (Midway's albatrosses have in their tissues as much of the industrial chemicals called PCBs as do Great Lakes bald eagles.) The biggest sources of coastal pollution are waste from farm animals, fertilizers and human sewage. They can spawn red tides and other harmful algal blooms that rob oxygen from the water, killing sea life. The Mississippi River, whose fine heartland silt once built fertile delta wetlands...