Yet another negative effect humans have placed on the environment has been found. A new study from the USGS has found fish swimming in Pennsylvania rivers that contain aspects of both males and females. Yes, we're talking about hermaphroditic fish.
The June 30th U.S. Geological Survey (USGS) led study published in the Environmental Monitoring and Assessment, which came to light on July 1st, states that marine life in Pennsylvania is suffering from endocrine-disrupting chemicals (EDC). The endocrine system controls hormones and the glands that produce them. It regulates everything from mood to sexual function and reproductive processes.
The study, which tested male specimen from the Susquehanna, Delaware and Ohio rivers in Pennsylvania were shown to possess female traits. Smallmouth bass and white sucker fish showed signs of the consequence of endocrine-disrupting chemicals. Researchers found male smallmouth bass had immature egg cells in their testes. Bass are also said to be susceptible to the intersex change when exposed to EDC. White suckers on the other hand did not have egg cells, but were found with the yolk precursor in their blood. These characteristics are caused by hormones and hormone-mimicking substances found in the water.
LiveScienece reports that the researchers brought in fish from 16 sites in the area. Smallmouth bass intersex fish were found in each site. If a site was found to be downstream from a water treatment plant; the fish’s condition was typically worse.
“The sources of estrogenic chemicals are most likely complex mixtures from both agricultural sources, such as animal wastes, pesticides and herbicides, and human sources from waste water treatment plant effluent and other sewage discharges,” said Vicki Blazer, a research fish biologist and lead author of the study.
Estrogen has been found to be a big water pollutant, Live Science reported back in May. Among the many man-made estrogens is Ethinyl estradiol. It is found in many birth control medications, and was found to be very influential and hard to clean up once in the waterway.
Estrone, a natural estrogen, was the most common chemical found in the water and soil samples the crew collected in this study. They can also be found in pharmaceutical drugs, personal care products, herbicides and pesticides.
“The prevalence and severity of the immature eggs in smallmouth bass corresponded with the percent of agricultural land use in the watershed above the collection sites,” said Blazer. “Chemical compounds associated with estrogenic endocrine disruption, in particular estrone, a natural estrogen, were also associated with the extent and severity of these effects in bass.”
Scientists are working to understand the long-term ramifications of this discovery. This includes how humans will reap what they sow. EDC exposure is said to be a player in low sperm count, testicular cancer in men, breast cancer, obesity and autism.