Quantcast
Environmental News for a Healthier Planet and Life

Intersex Fish Found in Three Pennsylvania Rivers Linked to Endocrine Disrupting Chemicals

A study led by the U.S. Geological Service (USGS) finds intersex fish in three watersheds of Pennsylvania and shows strong connections between these occurrences and increased pollution in waterways from endocrine-disrupting chemicals.

In fish and humans, endocrine disrupting effects include direct effects on traditional endocrine glands, their hormones and receptors such as estrogens, anti-androgens and thyroid hormones. Photo credit: RTD Photography/Flickr

The studyReproductive Health Indicators of Fish from Pennsylvania Watersheds: Associations with Chemicals of Emerging Concern, examined three species of fish in three separate watersheds of Pennsylvania to assess whether characteristics caused by hormones and hormone-mimicking compounds, such as immature eggs in male fish, were present. In aquatic environments, the presence of these intersex characteristics is widely used as a biomarker for assessing exposure to estrogenic chemicals, as well as anti-androgenic chemicals which inhibit development of male characteristics.

Male smallmouth bass from all sites sampled had immature eggs in their testes; prevalence was lowest in the Ohio drainage, intermediate in the Delaware and highest in the Susquehanna. While these findings were disturbing in and of themselves, the study was also able to draw a connection to the increased presence of intersex characteristics and areas of high agricultural use.

Fish collection sites in Pennsylvania drainages from 2007-2010. Image credit: Reproductive Health Indicators of Fish from Pennsylvania Watersheds

“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 Vicki Blazer, PhD, a research fish biologist and lead author of the study. “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.”

In other words, sites in the Susquehanna drainage  had a higher prevalence and severity of these effects than sites in the Ohio drainage and when compared against the percentage of agricultural land use, which is higher in the Susquehanna, a link was established.

Microscopic appearance of testicular tissue in smallmouth bass and sucker species collected at the Susquehanna and Ohio drainages in 2007-2008. Image credit: Reproductive Health Indicators of Fish from Pennsylvania Watersheds

Interestingly, the same connection could not be drawn from the data concerning wastewater treatment plants, leading researchers to conclude that there was no significant relationship between the number of wastewater treatment plants and the prevalence of immature eggs in male fish. Data did show, however, that the severity of intersex characteristics of male small mouth bass generally increased at downstream sites from wastewater treatment plants.

Read page 1

“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 wastewater treatment plant effluent and other sewage discharges,” said Dr. Blazer.

Percentage of male smallmouth bass with testicular oocytes collected in the three major river drainages in Pennsylvania in 2007-2008. Image credit:
Reproductive Health Indicators of Fish from Pennsylvania Watersheds

Endocrine Disruption and Agriculture: Not Only a Problem for Fish

If you are wondering why such a strong correlation could be drawn between agricultural use and water contaminated by endocrine-disrupting chemicals, then one need only look to the nation’s environmental law responsible for water pollution control and the chemical-intensive practices common to most conventional forms of agriculture. Under the Clean Water Act (CWA), agriculture is exempt from most water pollution standards and permitting requirements—even when it comes to pesticides. This leaves one of the largest sources of all kinds of pollutants completely unfettered and free to pollute, significantly contributing to everything from algal blooms and dead zones to intersex fish and pesticide contamination.

In fish and humans, endocrine disrupting effects include direct effects on traditional endocrine glands, their hormones and receptors such as estrogens, anti-androgens and thyroid hormones, as well as signaling cascades that affect many of the body’s systems, including reproductive function and fetal development, the nervous system and behavior, the immune and metabolic systems, the liver, bones and many other organs, glands and tissues. Hundreds of scientific articles have been published across the globe demonstrating how a broad selection of chemicals can interfere with the normal development at all ranges of exposure. Scientists discovered effects for some widely used chemicals at concentrations thousands of times less than federal “safe” levels of exposure derived through traditional toxicological tests. Whatever the exposure level, neither fish nor human are protected from most endocrine-disrupting chemicals present in our waterways.

EcoWatch Daily Newsletter

A ringed seal swims in a water tank at the Osaka Aquarium Kaiyukan on July 26, 2013. Kazuhiro Nogi / AFP / Getty Images

Ringed seals spend most of the year hidden in icy Arctic waters, breathing through holes they create in the thick sea ice.

But when seal pups are born each spring, they don't have a blubber layer, which is their protection from cold.

Read More Show Less
A volunteer sets up beds in what will be a field hospital in the Cathedral Church of St. John the Divine on April 8, 2020 in New York City. The cathedral has partnered with Mount Sinai Morningside Hospital and is expected to have more than 400 beds when opened. Spencer Platt / Getty Images

New York state now has more confirmed coronavirus cases than any single country save the U.S. as a whole.

Read More Show Less
Sponsored
Moroccan patients who recovered from the novel coronavirus disease celebrate with medical staff as they leave the hospital in Sale, Morocco, on April 3, 2020. AFP / Getty Images

By Tom Duszynski

The coronavirus is certainly scary, but despite the constant reporting on total cases and a climbing death toll, the reality is that the vast majority of people who come down with COVID-19 survive it. Just as the number of cases grows, so does another number: those who have recovered.

In mid-March, the number of patients in the U.S. who had officially recovered from the virus was close to zero. That number is now in the tens of thousands and is climbing every day. But recovering from COVID-19 is more complicated than simply feeling better. Recovery involves biology, epidemiology and a little bit of bureaucracy too.

Read More Show Less
Reef scene with crinoid and fish in the Great Barrier Reef, Australia. Reinhard Dirscherl / ullstein bild / Getty Images

By Elizabeth Claire Alberts

The future for the world's oceans often looks grim. Fisheries are set to collapse by 2048, according to one study, and 8 million tons of plastic pollute the ocean every year, causing considerable damage to delicate marine ecosystems. Yet a new study in Nature offers an alternative, and more optimistic view on the ocean's future: it asserts that the entire marine environment could be substantially rebuilt by 2050, if humanity is able to step up to the challenge.

Read More Show Less

Trending

A daughter touches her father's head while saying goodbye as medics prepare to transport him to Stamford Hospital on April 02, 2020 in Stamford, Connecticut. He had multiple COVID-19 symptoms. John Moore / Getty Images

Across the country, the novel coronavirus is severely affecting black people at much higher rates than whites, according to data released by several states, as The New York Times reported.

Read More Show Less