Already linked to problems with the development of the male reproductive organs, the controversial plastic additive bisphenol A (BPA) has been shown to induce profound behavioral changes in fish that are exposed to the chemical. BPA is widely used in plastic food containers and container liners and its safety is the subject of vigorous public debate.
University of Wisconsin-Milwaukee researcher Daniel Weber said the profound behavioral changes he observed after exposing the fish to BPA were similar to those he'd seen when exposing fish to mercury. Like developmental exposure to mercury, adult fish that had been exposed to tiny amounts of BPA as embryos had learning and memory problems. Weber's pilot study is the first to identify a neurobehavioral effect of BPA in zebrafish exposed to concentrations comparable to what humans might encounter in the environment.
"What was amazing is that exposure only happened at the embryonic stage," explained 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."
For the study, BPA, 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. The study notes that while the low concentrations of BPA didn't cause physical malformations or cardiac defects, behavioral deficits still occurred.
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 said. "We've seen that with children." Interestingly, Weber saw no differences in the resulting behaviors of male and female fish. He expected there might be as BPA is a kind of estrogen.
Related:
Discuss this article in our forum
Evidence links BPA to heart disease in later life
Asthma risk rises with BPA exposure
Exposure to plastics reduces semen quality
Cash register receipts the new BPA bogeyman
Source: University of Wisconsin-Milwaukee
