Close

A new study found that water polluted with synthetic human hormones can impact marine life. For instance, freshwater fish exposed to even the smallest estrogen from oral contraceptives could lead them to produce more female offspring and fewer populations in general.

The study described how synthetic human hormones from oral contraceptives were found in waterways near sewage treatment plants that are not designed to filter pharmaceuticals.

Scientists used a synthetic version of Ethinyl estradiol commonly used in birth control pills to see if those hormones affect the fish exposed to oral contraceptives in the water.

Human Hormones Affect Fishes

The researchers used killifish in their exp[eriments as these fish are tiny and easy to catch, making them perfect as test subjects as they do not require much space. They are a type of rare fish in that they have a placenta and give birth to a live young every 28 days to make up for dying quickly as they are popular with predators.

The study, published in Aquatic Toxicology, showed the fish produced fewer offspring when exposed to 5 nanograms per liter of synthetic Ethinyl estradiol compared to those that were not. The fish also gave birth to more female offspring than male offspring.

The researchers also found Ethinylestradiol in streams at over 60 nanograms per liter. Not only that, but they also found menopausal hormone therapy that is used to prevent osteoporosis and palliative treatment for breast cancer, MailOnline reported.

A human's body can only absorb a small amount of the medicines that they intake. Almost 90% of it gets flushed down the toilet and into the wastewater treatment facility. Although the sewage systems might be good at treating many things, they are not designed to remove the medications mixed with the water, said biologist Latonya Jackson, the lead author of the study from the University of Cincinnati.

She added that much of the residue gets flushed into the wastewater treatment plants when women who take birth control or are under hormone therapy go to the bathroom.

Read Also: 16 Species of Ultra-Black Fish Goes Invisible in the Ocean's Dim Backdrop

Human Hormones Can Affect Genetic Makeup of Fish' offspring

Aside from affecting the population of the fish, Jackson would also work with the Environmental Protection Agency to find out if the human hormones present in the water could affect the genetic makeup of the offspring of the fish.

Given that around 15 million women in the United States use birth control pills regularly, in which most of them are on Ethinyl estradiol, it is most likely that synthetic human hormones are present in the water.

A 2010 study revealed that estrogen in the US drinking water comprises less than one percent birth control pills, but local water systems did not test for Ethinyl estradiol.

Moreover, estrogen does not only get to the streams by means of sewage, but it could also come from livestock and dairy products. Studies show that estrogen in bodies of water led male fish to develop ovaries and other female characteristics. Additionally, a 2015 study from Washington State University found a connection between the growing decline in sperm count and Ethinylestradiol.

Read More: Walking Fish Are More Common Than You Think 11 New Species Found

Check out more news and information on Fish on Science Times.