People in the United States are probably exposed to levels of the hormone-disrupting chemical bisphenol A (BPA) at levels far higher than previously believed, according to a study conducted by researchers from the University of Missouri and published in the journal Environmental Health Perspectives.
“Our data raise grave concern that regulatory agencies have grossly underestimated current human exposure levels,” the researchers wrote.
BPA is a plastics ingredient commonly used to make water bottles and food containers, and to line cans of food, beverages and infant formula. Prior studies have found traces of the chemical in 90 percent of people tested. Because the chemical mimics the effects of estrogen, a male sex hormone and thyroid hormones, it can cause a wide array of developmental problems, brain damage and cancer.
Industry and government sources have consistently played down the danger from the chemical, however, claiming that the liver removes it from the body so quickly that its actual health effects are minimal even in cases of great exposure. This position is based on a 2002 study which has since been criticized for not using sensitive enough tests for the chemical.
In the new study, researchers used more sensitive blood tests on mice and monkeys that were fed a daily dose of BPA. Contradicting the findings of the 2002 study, they regularly found BPA concentrations equivalent to more than eight times the Environmental Protection Agency’s (EPA’s) exposure threshold.
The EPA has ruled BPA exposure of up to 50 milligrams per kilogram of body weight safe, but even this level has been criticized as dangerously high.
“In 2006, researchers found that BPA — at concentrations lower than those already found in pregnant women, fetuses, and adults, and well within the range of our typical human exposure — causes estrogen receptors to initiate unnaturally rapid responses, changing our basic cellular function,” writes Donna Jackson Nakazawa in her book The Autoimmune Epidemic.
“Significant effects can be seen at extremely low levels of exposure — parts per billion and even per trillion — levels currently present in blood samples taken from people as well as animals.”