How do PFAS interact with lake food webs?


New Hampshire Bulletin

Published: 06-13-2023 4:55 PM

This summer, Dartmouth scientists will be studying six New Hampshire lakes to learn more about PFAS in lake food webs. The study “will examine PFAS movement from lake sediment and water to fish and other organisms,” according to the project proposal. 

Research will build upon recent studies in New Hampshire lakes that detected PFAS in loon eggs. The lakes covered by the study include Arlington Mill Reservoir, Beaver Lake, Canobie Lake, Cobbetts Pond, Horseshoe Pond, and Robinson Pond. All but Arlington Mill Reservoir have been flagged for elevated PFAS levels in fish tissue by the Department of Environmental Services

Per- and polyfluoroalkyl substances, more commonly referred to as PFAS, are a family of fluorine-containing compounds that includes over 8,000 different chemicals. The impacts of these chemicals are still being studied, and are thought to have harmful developmental and reproductive effects on wildlife. 

In humans, there are several health issues linked to PFAS, such as various cancers and liver damage, as well as issues with thyroid, reproductive, and immune systems. 

“The reason that PFAS is on everybody’s radar these days is because there’s a real emerging literature on the human health effects based upon toxicological studies,” said Celia Chen, the project coordinator of the Dartmouth study.  

However, most of the impacts of PFAS in ecosystems and wildlife are still unknown. Last week the Executive Council approved $90,000 in grant funds to be awarded to Dartmouth for the new study, which was also funded in part by the U.S. Geological Survey and the university. 

Dartmouth researchers hope to better understand the pathways through which PFAS accumulate and move through aquatic food webs. This can be challenging, as bioaccumulation – the buildup of chemicals in fish – differs between organisms and PFAS compounds. 

“For things like aquatic food webs, the animals that we consume, in terms of human exposure, are generally fish or shellfish, things like that. And [PFAS] gets into those animals in different ways,” Chen said. 

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Researchers also aim to identify the types and amounts of PFAS compounds in state lakes, lake sediment, and lake organisms. 

“For regulatory organizations they want to know, for fish consumption advisories …, which species have high concentrations,” she said. “But we kind of want to know why.” 

Chen explained that she will be looking to see if biomagnification plays a role in PFAS concentrations in lake food webs, like it has in the case of mercury contamination. 

Biomagnification is the increase in concentration of a contaminant in the tissues of organisms at increasingly higher levels of the food chain. 

“We know for mercury, that things that are higher on the food chain – top predators – have higher concentrations than organisms lower on the food chain,” she said. “Is that the same for PFAS?”

To answer these research questions, a series of field studies will be conducted by Dartmouth researchers this summer. The goal is to present preliminary findings to the Department of Environmental Services in June 2024, but Chen emphasized that this relies upon an ambitious gathering of environmental samples. Those out fishing on the study’s selected lakes this summer can choose to assist researchers by donating their catch to the study

The study’s findings may be important for developing regulatory thresholds and adding to the body of research being used to assess health and ecological risks posed by PFAS. The results will also help inform state and federal entities with an interest in protecting freshwater resources.