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Can eating fish caught in freshwater be dangerous to your health?
Yes, say research scientists studying polyfluoroalkyl substances (PFAS) that have leached into drinking water supplies and local waterways.
The Environmental Working Group (EWG) came out with a recent report that says even eating one freshwater fish may contain enough of these pollutants, so it would be the equivalent of drinking one month of water contaminated with poly-fluoroalkyl substances. According to the study, eating just one fish could be 2,400 times greater than the Environmental Protection Agency (EPA) water health advisory.
According to a news release by EWG, “People who consume freshwater fish, especially those who catch and eat fish regularly, are at risk of alarming levels of PFAS in their bodies,” said David Andrews, Ph.D., EWG senior scientist and one of the study’s lead authors. “Growing up, I went fishing every week and ate those fish. But now, when I see fish, all I think about is PFAS contamination.”
“These test results are breathtaking,” said Scott Faber, EWG’s senior vice president for government affairs. “Eating one bass is equivalent to drinking PFOS-tainted water for a month.”
According to the Environmental Protection Agency, PFAS are found in water, air, fish, and soil locations across the nation and globe. In addition, the EPA says, “thousands of PFAS chemicals are found in many different consumer, commercial and industrial products.”
The EPA says it is working with researchers and partners across the country to identify how harmful these chemicals are to people and environments, as well as to find a way to remove them from drinking water and how to manage and safely dispose of them.
One of the ERG study’s authors, Tasha Stobier, Ph.D. of EWG, told NewsBreak that even four fish meals a year could double the PFAs in your blood.
Those same researchers say eating freshwater fish from any lake or stream has the potential to cause you harm. However, because the water in large lakes doesn’t circulate much, PFAS particles are more readily picked up by fish in their food and passed on to you when you catch and eat them. Findings in the study state that locally caught freshwater fish are far more polluted than commercially caught fish from the ocean.
Called “forever chemicals,” exposure to PFAS can cause “cancer, liver damage, decreased fertility, and increased risk of asthma and thyroid disease,” according to the U.S. Centers for Disease Control and Prevention (CDC).
PFAS have also been linked to increased cholesterol levels, changes in liver enzymes, decreased vaccine response in children, increased risk of high blood pressure or pre-eclampsia in pregnant women, lower birth weight, and increased kidney or testicular cancer.
The EWG study is the first to link U.S. fish consumption to PFAS found in blood samples. The study also compares contaminant levels in freshwater fish to seafood fish sold commercially.
Study samples came from 501 fish fillets collected from 2013 to 2015 from across the U.S. Of those, 152 fish samples were tested in the 2015 Great Lakes study, and all of those fish had overall higher levels of PFOS (Perfluorooctane sulfonic acid) when compared to those in the National Rivers, and Streams Assessment conducted in 2013.
Because water in rivers and streams gets flushed, these waters have less PFAS pollution than the Great Lakes and other smaller lakes and ponds.
Included in the EWG work was a comparison of PFAS in freshwater fish to commercially caught fish tested from 2019 to 2022. Those freshwater fish had 278 times higher levels of PFAS than commercially caught fish from the ocean.
Because of the decrease of PFOS by manufacturers, those levels are decreasing in rivers and streams. However, Andrews noted chemical levels are still so high that eating fish is likely to impact one’s serum levels.
EWG has long called for strict regulation of PFOS and the other toxic “forever chemicals” known as PFAS. They have also asked for more tests of food such as fish since diet is thought to be a significant source of PFAS exposure for Americans.
lar issue for “communities with environmental justice concerns, whose survival often depends on eating freshwater fish they’ve caught,” says the new EWG news release
EWG found the median amounts of PFAS in freshwater fish were 280 times greater than forever chemicals detected in some commercially caught and sold fish. In addition, the testing data from the Environmental Protection Agency and Food and Drug Administration showed that consuming a single meal of freshwater fish could lead to similar PFAS exposure as ingesting store-bought fish every day for a year.
Freshwater fish are an important source of protein for many local people. PFAS contamination threatens those who cannot afford to purchase commercial seafood. In addition, communities that depend on fishing for sustenance and traditional cultural practices are inordinately harmed. This makes exposure to chemical pollutants in freshwater fish a textbook case of environmental injustice.
“Identifying sources of PFAS exposure is an urgent public health priority,” said Stoiber.
One glimmer of good news is that the study found that the biggest contributing factor to PFAS levels came from PFOS, responsible for about 74 percent of total findings, have largely been phased out from manufacturing. “Perfluorooctane sulfonic acid (PFOS) is the PFAS that can build up to levels of concern in fish,” states the Minnesota Department of Health.
The FISH Project
The newest studies on freshwater fish are adding to a catalog of water woes caused by people. Minute particles of mercury found in fish have long been known to cause problems for pregnant women. More than a decade ago a study (the FISH project) was done along the North Shore to improve advice given to women who ate fish.
The Fish are Important to Superior Health (FISH) project started after a 2011 study by the Minnesota Department of Health (MDH) showed that 10 percent of newborns tested in the North Shore – Arrowhead region had mercury above levels of concern in their blood. Too much mercury can cause lasting problems with understanding and learning.
That study spurred collaboration among Sawtooth Mountain Clinic, Grand Portage Health Service, North Shore Health, Grand Portage Band of Lake Superior Chippewa Trust Lands, and MDH to reduce mercury exposure in women in the area and pilot an in-clinic screening for high mercury exposure. Nearly 500 women from Cook County, Grand Portage, and the surrounding area participated in the FISH Project.
Participants provided information about which fish they ate and how often they ate fish. They also had a blood sample analyzed for mercury and healthy fatty acids. In addition, they received information about healthy diets, including which type (species) of fish to eat and how often they can eat.
As former CEO of the Sawtooth Mountain Clinic Rita Plourde pointed out at the time, “Fish and fishing is our history and a strong part of the culture of the communities along the North Shore. Our board of directors and staff appreciate any opportunity to improve our patient care and community health. Together with our patients, we wholeheartedly agreed to do whatever was needed to educate and ultimately reduce mercury exposure in women who are or may become pregnant, thereby reducing mercury levels in future babies. Now we know we can eat fish wisely and give birth to healthy babies!”
Some women in the FISH project were asked to participate in a follow-up clinic visit six months after their initial visit. Changes at the follow-up were positive: the project did not cause women to eat less low-mercury fish, and fatty acid levels did not change. However, many women said they ate more fish. Mercury levels had declined in the follow-up group and the participants with elevated mercury reduced their consumption of fish species shown to contribute most to higher mercury exposure.
“We want women and children to eat fish. The benefits outweigh the risks if they choose fish low in mercury and other contaminants,” said Pat McCann, research scientist for MDH.
Minnesota’s health department has fish consumption guidelines for lakes that tell how much and what type of fish can be safely eaten.
Ontario lakes study
Our neighbors to the north have been engaging in long-range research whose results could profoundly impact the planet’s fresh water.
The International Institute for Sustainable Development (IISD) is based in Winnipeg, but its outdoor lab is not far from the Northwest Angle.
The Experimental Lakes Area (ELA) consists of 58 lakes and watersheds east of Kenora. It has been called the world’s largest freshwater laboratory. Lakehead University in Thunder Bay has contributed to the ongoing exploration at ELA.
Currently, IISD Experimental Lakes Area is studying how microplastics and antidepressants affect aquatic life.
Microplastics, which are five millimeters or smaller plastic particles, have been found in fish, turtles, birds, and zooplankton. Microplastics move through wind currents and watersheds, ending up everywhere. These pollutants block digestive tracts and alter feeding behavior. There is also evidence that microplastics and smaller units called nano plastics can move from the stomach of a fish to its muscle tissue, the portion that people eat.
These microplastics, similarly to PFAS, are a large suite of contaminants; there are dozens of polymer types that alone make up 4,283 additives detected in human blood and urine. These additives include flame retardants, plastic stabilizers, and colorants.
According to authors Cayla Cook and Eva Steinle-Darling, who authored a story for Water ONLINE April 13, 2021,
“Microplastics and PFAS are often found together in the environment and recent research has indicated that microplastics may increase PFAS toxicity (Pramanik et al. 2020; Le Bihanic et al. 2020; Sobhani et al. 2021).
So, concludes the long report by Cook and Darling “The co-occurrence of these two contaminants may come as a surprise to the public, utilities, or industries as each has historically been treated as an isolated issue; however, this is not always the case. Simultaneous microplastics and PFAS monitoring by utilities and industries can begin to shed light and increase knowledge on this co-occurrence. Moreover, source control of PFAScoated textiles which shed microfibers could have a concurrent, positive impact on environmental and potable water quality. Increasing our understanding on their co-occurrence and considering concurrent mitigation strategies, including source control and treatment technologies, will lead to long-term sustainable solutions.”
Let’s hope so. At least for the fish and smaller life that live in our once thought to be “pristine” waters.
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