Low levels of BPA cause hyperactivity and learning impairment - http://www.sciencedaily.com/releases/2012/04/120404101812.htm


The results he observed were similar to those he'd seen when exposing the fish to mercury during their early development -- profound behavioral changes occurred not only immediately after hatching, but also in adulthood.

Like developmental exposure to mercury, adult fish that had been exposed to tiny amounts of BPA as embryos had learning and memory problems, compared to fish that had not been exposed.

Weber, a researcher with the NIEHS Children's Environmental Health Science Core Center at UWM, collaborated with Robert Tanguay at Oregon State University. Their pilot study, funded by the center, is the first to identify a neurobehavioral effect of BPA using a zebrafish model exposed to concentrations comparable to what humans might encounter in the environment.

"What was amazing is that exposure only happened at the embryonic stage," says Weber, "but somehow the wiring in the brain had been permanently altered by it. It's an example of why children are not just little adults when it comes to gauging the effects of contaminants."

BPA is widely used in plastic food containers and container liners. Conflicting reports of its safety have made it the subject of vigorous public debate. Amid the debate, the Campbell's Soup Company recently announced it would be removing BPA from the linings of the company's soup cans as soon as a viable alternative is found.

At issue is the amount of exposure with some studies concluding BPA is a health risk only at concentrations that are higher than environmental levels. Results of this study, however, suggest that lower concentrations may be more potent during early-life exposures. This study tested three different small amounts considered environmentally relevant.

The compound, which mimics the hormone estrogen, was added to the aquatic environment of fish embryos in their first two days of life. Then they were returned to clean water for the ensuing 10 months while they grew into middle-age adulthood.
Since zebrafish mature in only a few months, they are a useful model to test effects of toxicity over a lifetime. Scientists also can control the conditions and timing of chemical exposure with zebrafish because the embryos can live outside the mother.
Tanguay says the low concentrations of BPA they used don't cause physical malformations or cardiac defects. But even without physical abnormalities, behavioral deficits can still occur, as this study indicates.

Weber says multiple behavioral outcomes are not only changed by BPA, but those behaviors -- immediate hyperactivity and later-stage learning impairment -- may be inter-related.

"Being hyperactive -- or even hypersensitive to an environmental stimulus -- makes it difficult to learn," he says. "We've seen that with children."

Original paper found here - http://www.sciencedirect.com/science/article/pii/S0300483X1100463X