ILL WIND: A young boy wears a mask against pollution in Linfen, China. Preliminary results from a study conducted in Tongliang, China, reveal that children exposed to highly polluted air while in the womb had more changes in their DNA—and a higher risk of developmental problems—than did those whose mothers breathed cleaner air during pregnancy. Image: Peter Parks AFP/Getty Images
- A central goal of molecular epidemiology is to tie environmental factors to genetic changes that contribute to disease.
- Some biologists have questioned the approach, because few candidate molecular markers of susceptibility, exposure or early disease have yet been proved to foretell future illness.
- Now researchers may have found the best test case yet for environmental molecular epidemiology: a city in China whose coal-fired power plant was shut down in 2004.
- Preliminary analysis shows that children born in 2002, when the plant was still operating, have smaller heads and lower scores on developmental tests than those born a year after the plant closed. They also have correspondingly higher levels of pollution-related genetic abnormalities.
Editor's Note: This story was published in the August issue of Scientific American.
A few heaping piles of scrap metal and a rusty coal shed are all that is left of the power plant that until recently squatted like an immense, smoke-belching dragon in the middle of Tongliang, a gray city of 100,000 in south-central China. As we walk toward the shed, a Belgian Shepherd begins barking furiously, jerking its iron chain and baring sharp teeth. A brown-eyed face peeks out from the open doorway—it belongs to a girl in a stained shirt, holding a tabby cat that jumps away to hide under a slab of concrete as we approach. The girl is no more than six or seven years old and appears to be living in the shed with her father, who watches us warily from within.