Chemicals that mimic hormones in the body, known as endocrine disruptors because they can confuse and affect the endocrine system, cause irreversible changes to the brains of turtles, according to new research conducted by University of Missouri researchers.
Dr. Cheryl Rosenfeld and Scott Givan collected cells from the brains of turtles who were exposed to ethinyl estradiol, a synthetic hormone used in birth control pills, and Bisphenol-A, an endocrine-disrupting chemical that is used to produce hard, polycarbonate plastic and is often found in food packaging. Because BPA easily leaches into products it touches, such as the acidic tomatoes in a can that is lined with BPA, nearly every person in the United States is likely to have traces of BPA in their urine, as previous research has shown.
According to Rosenfeld and Givan’s work, the endocrine disruptors changed the behavior of turtles in such a way that they essentially rewired the gender of turtle’s brains, as the University of Missouri’s Decoding Science blog puts it.
Male turtles exposed to either chemical were found to “act like females” in their behavioral responses. The research has important implications for wildlife because both BPA and ethinyl estradiol “have been identified in all aquatic environments tested to date, including rivers and streams,” Decoding Science explains. “Thus, exposure of turtles and other species that inhabit such environments can potentially lead to irreversible effects.”
How birth control and plastics chemicals end up in the water
Chemicals from birth control pills are present in the water supply due to the phenomenon known as pharmaceutical pollution. Researchers say that drugs pollute waterways when nursing homes or hospitals flush unused products down the toilet.
Nursing homes especially “have often been guilty of flushing medications down the toilet or drain after a patient dies or is transferred to another facility,” Harvard Medical School’s newsletter wrote in 2011. Additionally, “the typical American medicine cabinet is full of unused and expired drugs, only a fraction of which get disposed of properly.”
And researchers have identified industrial waste-water as one potential source of BPA pollution in aquatic waterways.
The lesson for humans
Of course turtles and humans don't respond to environmental exposures the same way, but the impact that BPA has on the amphibians' brains still carries important lessons for people, Dr. Rosenfeld explains. She says that her research looked at the turtle’s cortex and hippocampus specifically, two parts of the brain that also guide cognition, learning and memory in humans. "They're governing the same types of processes in turtles and humans,” she tells ConsumerAffairs.
Researchers like Dr. Rosenfeld are particularly concerned about the impact that endocrine disruptors have on the developing brains of fetuses and babies, who are more vulnerable to chemical exposures than adults. “BPA is one chemical that can easily cross the placenta,” Rosenfeld says.
Though it’s difficult for anyone to avoid BPA entirely, Rosenfeld says the best way for expectant mothers and other concerned people to minimize exposure is to avoid canned food and eat fresh as much as possible. In the long-term, with United States regulators unwilling to say that BPA is harmful or remove it from consumer products, Rosenfeld would like to see companies label products that contain endocrine disruptors. "If you're not going to regulate it, at least let the consumer know which products contain it," she said.
Plastics industry cries Fake News
The idea of labeling products with endocrine disruptors like BPA is one that will likely never win support from the American Chemistry Council, the group that represents the plastics industry. One recent blog post by trade group spokeswoman and researcher Dr. Steven Hentges describes research on Bisphenol-A alternatives, which are often still from the Bisphenol chemical family, and therefore may pose similar problems, as “Fake news.”
“If BPA-Free were a substance, it’s now being studied — and that’s the origin of the fake news,” Hentges proclaimed.
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