Ramji Bhandari, a MU assistant research professor and a visiting scientist at the U.S. Geological Survey, is conducting a study through USGS and is finding a synthetic hormone in human birth control pills that can cause defects in fish.
Bhandari said birth control pills are not totally absorbed in the body and can reach waterways by being flushed down toilets, poured down sinks and excreted in urine. The estrogenic chemical can gather in fairly heavy doses.
The recent USGS survey found that fish exposed to this synthetic hormone called 17a-ethinylestradiol, or EE2, produced offspring that struggled to fertilize eggs.
“The defect actually goes to the next generation, or even goes to the third and fourth generations, which is called transgenerational,” said Bhandari. He said transgenerational organisms were never exposed to the chemical directly, but their grandparents were.
According to the survey published in late March, the next generation of the originally exposed fish suffered a 30 percent decrease in their fertilization rate.
Bhandari expanded his experiment from past experiments by working with a chemical called BPA, which is used widely in plastics. The BPA had a similar effect on Japanese medaka fish used for the research.
“We used Japanese medaka fish because this fish has a shorter generation and can reproduce quicker than slow reproducing species such as smallmouth bass.”
Bhandari said over the years, researchers have seen fish that have developed ovaries where their testes should be, and evidence is leading scientists to believe EE2 and BPA contributed to these defects.
“The USGS surveyed a lot of aquatic habitats in the United States and found the vast population to have these defects, so that means that these studies indicate that these aquatic habitats are somehow contaminated by estrogenic chemicals,” Bhandari said.
“The estrogenic chemicals work just as the natural hormones do in the body, so they act as signals turning on estrogen pathways,” said the recent study’s co-author, Don Tillitt, research toxicologist at USGS’s Columbia Environmental Research Center in Missouri.
Both researchers said they plan to continue their work.
“We know these defects can occur in fish, as well as other species, so the next step that we have to take is look at environmental concentrations,” Tillitt said.
Bhandari said, “We would like to do more and more work with the water and other chemicals and see whether the environmental concentration has similar effects with the natural population.”