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PFOS found in most Seneca Lake fish at hundreds of times NYS limit

  • / Updated:
  • Peter Mantius 

When the state tested 34 lake trout and yellow perch from Seneca Lake for the toxic ‘forever chemical’ PFOS in 2020, most were found to be contaminated at hundreds of times the state’s enforceable limit for identical compound in public drinking water.

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For 27 of the tested fish (79 percent), PFOS exceeded 2,000 parts per trillion, and five fish registered more than 15,000 ppt. 

The chemical is considered so hazardous that the state Department of Health requires public water systems to undergo expensive cleanup measures if it exceeds 10 parts per trillion in public tap water.

But the Health Department is silent on the potential risks of eating Finger Lakes-caught fish that are many times more contaminated. 

DOH even urges anglers “to eat up to four meals per month from the state’s fresh waters,” except when the the agency specifically warns about contamination in particular waterbodies. No such warnings for PFAS contamination apply to fish caught in the Finger Lakes, including Seneca Lake. (Warnings do apply to certain fish in Owasco and Canadice lakes for PCBs or mercury.)

DiSanto Propane (Billboard)

The previously unpublished test results on Seneca Lake fish were obtained through a Freedom of Information Law (FOIL) request. They tend to confirm the findings of a recent national study, which concluded that PFAS class chemicals — particularly PFOS (perfluorooctane sulfonic acid)— accumulate dangerously in freshwater fish.

Anglers should be informed of the FOIL data, given the potential health hazards, said Dan Corbett, president of Seneca Lake Pure Waters Association (SLPWA).

“As a fisherman and consumer of local fish, this information will affect my future plans on any consumption,” said Corbett, a retired engineering director at Corning Glass.

The Health Department doesn’t issue its “DON’T EAT” fish warnings until PFOS exceeds 200,000 parts per trillion.

But the state has never even tested for PFAS class chemicals in fish from six of the 11 Finger Lakes — Skaneateles, Owasco, Keuka, Canandaigua, Honeoye and Conesus — according the response to WaterFront’s FOIL request and a lengthy joint statement to WaterFront from the state Department of Environmental Conservation and DOH.

The DEC has tested fish from five of the Finger Lakes for PFAS, but state officials provided data for only three of those — Seneca, Otisco and Canadice lakes. 

The agency declined to give results of 2019 PFAS tests of lake trout from Cayuga Lake or 2021 tests for rainbow smelt from Hemlock Lake. The denied Cayuga results — now nearly four years old — were said to be “awaiting analysis,” while the Hemlock results were “not subject to FOIL” because they were still in draft form.

In a March 8 statement to WaterFront, the agencies said: “DEC is measuring PFOS levels in hundreds of fish from many New York waterbodies annually and we are finding most fish sampled from New York waterbodies have PFOS levels below advisory levels set by DOH … DEC is working with the DOH to develop a sampling plan to conduct fish contaminant analysis, and the Finger Lakes are being considered for this year’s sampling.” (Read the entire DEC/DOH statement here.)

The 2020 test results released under FOIL show that Seneca Lake fish were far more contaminated with PFOS than fish from either Otisco or Canadice lakes.

Only nine of 20 fish tested from Otisco showed PFOS above 2,000 ppt, and the highest reading was 2,950 ppt. Only three of 22 fish from Canadice registered more than 2,000 ppt, and the highest was 2,390 ppt.

Five Seneca Lake fish had PFOS readings ranging from 15,500 ppt to 34,700 ppt.

Corbett said SLPWA is currently working with the Finger Lakes Institute and Seneca Lake’s National Lake Trout Derby to study contamination — including PFAS chemicals — in local fish. But he said the analysis is incomplete and no results are ready for release.

The PFOS contamination in Seneca Lake fish were generally in line with a recent national study published in the journal Environmental Research. It was conducted by scientists from the Environmental Working Group (EWG) in Washington, D.C., and Duke University.

Researchers for the EWG study found the median level of PFOS in 501 freshwater fish collected nationwide by the U.S. Environmental Protection Agency was 8,410 ppt.

The study concluded that freshwater fish tended to be far more contaminated with PFAS chemicals, and PFOS in particular, than were commercially caught fish sold in grocery stores and supermarkets.

New York State officials acknowledge that certain PFAS chemicals “accumulate in fish, and levels in fish can be many times greater than in the water” they swim in.

PFOS accumulates much more quickly than any of the thousands of other chemicals in the PFAS class, and it is typically the central focus of federal and state tests for PFAS in fish. 

PFOS quickly reaches the bloodstream of anglers who eat contaminated catches. 

On average, Americans had PFOS in their blood at 4.3 ppt in 2018, and one person in 20 registered as high as 14.6 ppt. People who test between 2 and 20 ppt in their blood face “potential adverse effects,” the National Academies of Science reported last July.

PFAS levels in blood have been steep decline in recent years, as manufacturers like 3M have been phasing out the manufacture and use of the chemical class. 

However, eating freshwater fish can cause those blood contamination levels to spike higher.

For example, a 2022 study of anglers near Onondaga Lake found that the most frequent consumers of freshwater fish had median levels of PFOS in their blood at 9.5 times the U.S. median, as well as traces of PFDA, another PFAS compound, at 26.9 times the U.S. median.

In their study, EWG scientists reported that eating just one freshwater fish a year (contaminated at the EWG average of 8,410 ppt) would be as risky as drinking for a month tap water tainted with PFOS at 48 ppt –nearly five times the DOH’s enforceable limit.

Eating that EWG ‘average’ fish once a month would raise contamination levels in blood by 11.07 ppt. Eating the fish weekly — as the New York DOH recommends — would raise it by 47.96 ppt, researchers calculated. 

Exposure to PFAS chemicals has been linked to kidney and testicular cancer, infertility, developmental problems in children and other health issues. Despite the known risk to humans, the chemicals continue to be used in making a host of consumer goods, including stain-resistant products, cosmetics, dental floss, food packaging and clothing.

This European Environment Agency graphic shows health effects of PFAS exposure on men and women.

Scientists are divided on what levels of PFAS exposure threatens public health. And state and federal officials are not even close to agreeing where thresholds should be set for health advisories or enforced cleanups.

For example, the EPA for years set its health advisory guideline for PFOS at 70 ppt. But last June the agency slashed that unenforceable threshold to 0.02 ppt, citing more recent health studies.

David Q. Andrews, an EWG scientist, said the study he co-authored points to a need for wider testing, more online sharing of test results and revised warnings about eating freshwater fish.

“In general, freshwater fish are contaminated at such a level that exposure due to consumption is likely a bigger concern even than contaminated drinking water,” Andrews said in a recent interview with WaterFront.

The federal test data EWG relied on included fish caught near the New York shores of lakes Erie and Ontario, which frequently registered PFOS above 20,000 ppt. EWG also cited data from several New York rivers, which ranged up to 72,400 ppt for the Hudson.

In its 2020 study of PFOS in Seneca Lake fish, the DEC collected lake trout at the north end of the lake “with collections extending down the east side to the Ovid/Romulus area.” A few lake trout were also taken from “the west side of the lake around mid-lake.” The yellow perch were collected aground Geneva and the northwest area of the lake, the agency said.

News reports about the EWG study were posted on several websites frequented by Finger Lakes anglers. Many who responded with online comments expressed skepticism about its conclusions about the potential health risks of freshwater fish.

Andy Anderson, posting on the Fishing Report Upstate NY website, called the study “a corporate money grab.”

Anderson continued: “More and more people are eating their catches these days. Funny, I just asked my 9-month old’s pediatrician if freshwater fish was OK for him to try, provided no (state) advisories. He said it was perfectly fine.”

Andrews of EWG said that while consulting a pediatrician is a “reasonable approach,” many doctors don’t have up-to-date information about the prevalence of PFOS in freshwater fish or the health risks involved. 

He said the EPA should promptly set new nationwide health advisories for eating freshwater fish.

Even so, Andrews acknowledged that “there’s an underlying lack of trust even in fish advisories.” He said it wasn’t unusual for people to eat the fish they had caught while standing next to a state DON’T EAT the fish warning.