Mercury in Adirondack Park fish raises health concerns

Adirondack Park’s pristine waters hide contaminant dangers in fish

By Mike Lynch

The Adirondack Park, containing more than 3,000 lakes, ponds, rivers and streams, is an angler’s paradise.

Record brook trout can be caught in backcountry ponds, northern pike can be plucked from big lakes and lake trout can be hooked with trolling lures. 

But despite the unspoiled look of Adirondack waters, many of the fish contain contaminants that can be harmful, especially to children and pregnant women.

The main concern is mercury, although scientists have been studying whether “forever chemicals,” such as per- and polyfluoroalkyl substances, are now making their way through the food chain.

The issue of mercury isn’t a secret. Scientists raised the alarm about it being in the environment decades ago, along with acid rain, from coal-fired power plants in the Midwest and other sources. The state Department of Health has been issuing advisories about limiting the number of fish people should eat for years. 

But it’s also unclear if the mercury problem will be going away anytime soon, even though environmental regulations have severely limited the airborne pollutants making their way to the Adirondacks. 

“We’re not seeing very strong decreases (of mercury) in fish,” said Charles Driscoll, a Syracuse University professor who has studied watershed health in the Adirondacks for decades.

He clarified there is a lot of variability in mercury contamination and that some water bodies are in better shape than others. For instance, western lakes have been hit harder by airborne pollutants and acid rain. In addition, weather patterns, particularly storms, play a factor in releasing mercury from soils into water. 

But the question is worth asking: Why is the amount of mercury in some fish not decreasing? It’s a complicated situation that is currently being analyzed by scientists. 

Several forms of mercury appear to be decreasing in the environment, based on studies at SUNY College of Environmental Science and Forestry’s Huntington Forest in Newcomb, Driscoll said. However, one form of mercury, particulate mercury, caused by burning biomass appears to be increasing, counteracting positive trends. 

Another issue, says Peter McIntyre, director of Cornell University’s Adirondack fishery program, is that you can’t just rid mercury from the environment. “Once you dump a bunch of mercury in a system, it’s going to be there for quite a long time,” he said. 

That mercury in the soil leaches into water bodies and under the right conditions transforms to methyl mercury, which is considered harmful to animals and humans and makes its way through the food web, impacting everything from insects to bats, birds and fish. 

Now Cornell, SUNY ESF and Syracuse University are looking at whether climate change may be creating conditions that create more of this dangerous form of mercury.

Lakes are getting warmer and browner, and staying ice-free longer. This is causing the water to contain less oxygen, which is believed to promote the formation of methyl mercury from its nontoxic inorganic form. 

“Other studies have shown us that there is an association between anoxia (low oxygen levels) in the water column and mercury that ends up in organisms,” said Stephen Jane, who has worked on the study for Cornell. “Whether or not that translates into the amount that ends up in those sort of upper trophic level organisms like fish that people consume, it’s a little premature to say.” 

Jane said results from that study are expected within the next six months. 

Driscoll is more direct. 

“Climate change is working against the recovery of fish,” Driscoll said.

Health department advisory

The state health department has updated its fish consumption advisory in the Adirondacks in 2022 and statewide this year. 

“It’s not necessarily that the mercury levels have gotten worse in fish,” said Audrey Vangenechten, DOH fish advisory outreach program manager. “It’s that DOH revised our guidelines to be more protective.”

The previous advisory for the Adirondacks pertained to specific water bodies and there were 65 advisories compared to the roughly two dozen now in place for locations. The new advisory is more species-specific as opposed to location-based. For instance, it recommends that no one eat walleye greater than 19 inches.

It relies on data gathered by the state Department of Environmental Conservation, which samples about 1,500 fish from 50 waters a year.

RELATED READING: New York’s top doctor: Adirondack fish offer nutrition; but eat sparingly

The advisory is broken into two categories. The sensitive population — women who can get pregnant under 50 and children under age 15—and the general population. 

Fish such as walleye, lake trout, bass, and large yellow perch generally contain the most mercury. The health department recommends that the sensitive population refrain from eating these fish and that the general population only eat one meal of eight ounces per month. 

The state advises that some other fish, such as trout and panfish, should be included in only four meals per month, with the sensitive population being restricted to one. 

The fish with higher mercury levels generally are larger and older and feed on younger fish, which have mercury. Other species with lower levels, such as brook trout, will still have mercury but feed on things like insects, which have less mercury.

What happens if you eat the fish?

Mercury poisoning is rare but one risk of eating too many fish is it can cause mercury to build up in the body over time. (It can also leave through detoxing over time.) Too much mercury can cause fatigue, memory problems and hair loss. It’s especially problematic for fetuses and young children, and it can cause permanent neurological or heart damage. 

But fish still have health benefits and doctors often recommend continuing to eat them, if you fall in the right category. 

“Fish, of course, are an excellent source of protein,” Darci A. Beiras, head of pediatrics at Adirondack Health in Saranac Lake, said. “They have iron, they have the omega fatty acids, which help with brain development. So, it’s a matter of balancing out that intake.” 

She recommends people pay attention to their portion sizes and look at the state and federal guidelines, a message echoed by the DOH. That might mean eating smaller trout as opposed to large bass or walleye, which may be older and have accumulated a lot of contaminants. 

“Fishing is still really, really fun,” Vangenechten said. “And eating locally caught fish is still good for you. Just be aware of the advisories and make smart choices.”

But the presence of contaminants still gives some people pause. 

Valorie Titus is a board member for the New York chapter of Backcountry Hunters and Anglers, a national organization, and a natural resources faculty member at Paul Smith’s College. 

She calls the risks from toxins “disheartening.” She’s not opposed to eating the fish and encourages people to get out and experience the outdoors, but just do research ahead of time to understand the risks. 

“It definitely is concerning as a parent to see these toxins are still an issue, even in a place as pristine as the Adirondacks,” she said.