ScienceNot yet confirmed elsewhere1 publisher2 min readPublished
Some Quebec fish, seafood and meat samples outpace tap water as a source of PFAS intake
Université de Montréal chemists tested Quebec grocery food for 76 PFAS and put intake from some fish, seafood and meat samples above tap water's. The estimates make diet a PFAS pathway on the scale of drinking water, one that treating tap water leaves untouched.
The Scientist · Science desk
What happened
- Once typical consumption was factored in, grains emerged as an important source of exposure despite modest concentrations, because bread and pasta are eaten in large quantities.
- Across modeled diets running from omnivorous to little or no meat, estimated total PFAS intake fell as animal products were cut.
- The work follows earlier research by the same Universite de Montreal group showing that Quebec's drinking water is contaminated with PFAS.
Why it matters
- decision Food monitoring that ranks items by PFAS concentration alone would underrate grains, since intake depends as much on how much of a food people eat.
- constraint Going plant-based lowers estimated intake but cannot remove it, because grains contribute PFAS in every diet the team modeled.
- exposure Heavy fish and seafood eaters are the most exposed group in the omnivore modeling, since those foods held both the highest concentrations and the widest mix of compounds.
The tap-water comparison holds for "some samples" of fish, seafood and meat, according to phys.org's account of the study, published in the Journal of Food Composition and Analysis [1][3]. PFAS showed up across many food categories, sometimes at levels that matched drinking water's contribution to daily exposure [2]. The account does not report how many samples were tested, which water concentrations were used, or the intake figures behind either comparison.
Exposure here is modeled. Researchers weighted measured concentrations by the amount of each food people typically eat [7]. That weighting reorders the list. Fish averaged about 1.9 ng/g [5], roughly two and a half times the top of the range reported for dairy and plant-based foods [17]. Sauvé put the point in terms of grains. "To estimate our exposure to a contaminant, we must consider both its concentration in the food and the amount of the food that we consume," he said. "Since we eat such large quantities of grain products, the effect of the contamination is amplified." [8]
The chemistry explains why animal foods top the concentration list. The PFAS found in food were mainly long-chain compounds, which generally stay in the body longer than short-chain ones [12]. PFOS and PFOA can build up in a small aquatic creature, then in the fish that eats it, then in a larger fish, rising at each stage as mercury does [13]. Land animals are likely to accumulate PFAS from their diet too, but most are herbivores and sit lower on the food chain [14].
Plants take up little long-chain PFAS, which stays bound to soil particles, while smaller, more mobile molecules reach them more easily [15]. "This highlights an important fact: not all PFAS follow the same pathway in the environment," Sauvé said [16].
The thing this doesn't tell you is what any one shopper takes in. The estimates apply typical consumption to foods bought in one province's grocery stores [1][7], and the samples that beat tap water were a subset [3]. I'd still take the direction seriously. That subset fell in fish, seafood and meat, the foods holding the long-chain compounds that accumulate up food chains and stay in the body longer [3][13][12].
What to watch
- Release of the sample counts and daily intake figures behind the food-versus-water comparison in the Journal of Food Composition and Analysis paper.
- Blood testing that checks whether Quebec residents who eat more fish and seafood carry higher levels of long-chain PFAS such as PFOS and PFOA.
- Whether Canadian exposure guidance on PFAS begins to count dietary sources alongside drinking water limits.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
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- [1]
A team led by Sebastien Sauve, a chemistry professor at Universite de Montreal, analyzed foods sold in Quebec grocery stores for 76 different PFAS compounds; the findings are published in the Journal of Food Composition and Analysis.
- [2]
The team found PFAS in many food categories, sometimes at concentrations high enough to contribute to daily exposure as much as drinking water does.
- [3]
Estimated PFAS intake from some samples of fish, seafood and meat was considerably higher than from water.
- [4]
Several years ago, a research team led by Sauve showed that Quebec's drinking water is contaminated by PFAS.
- [5]
On average, PFAS levels were approximately 1.9 ng/g in fish, 1.3 ng/g in seafood and 1.2 ng/g in meat; dairy and plant-based products generally had lower concentrations, ranging from 0 to 0.75 ng/g.
- [6]
The modeled exposure estimates factored in the quantities of food typically consumed.
- [7]
To estimate what enters the body, the team factored in typical consumption quantities; by this measure grains emerge as an important source of exposure because they are consumed in large quantities as bread, pasta and other grain products, even though they are not among the most contaminated foods.
- [8]
"To estimate our exposure to a contaminant, we must consider both its concentration in the food and the amount of the food that we consume. Since we eat such large quantities of grain products, the effect of the contamination is amplified."
- [9]
The team modeled PFAS exposure for diets ranging from omnivorous to little or no meat; estimated total PFAS intake was lower for people who consume fewer animal products.
- [10]
Grains contribute significantly to exposure in all diets, so switching to a plant-based diet will reduce some exposure but won't eliminate PFAS entirely.
- [11]
Animal proteins account for a substantial share of exposure among omnivores; fish and seafood contain both the highest concentrations and greatest variety of PFAS detected in the study.
- [12]
Among the 76 PFAS tested, it was mainly long-chain PFAS that turned up in food; long-chain PFAS generally stay in the body longer, while short-chain PFAS are eliminated more quickly.
- [13]
Certain long-chain PFAS, including PFOS and PFOA, can bioaccumulate in organisms and move up the food chain, from small aquatic creatures to fish to larger fish, with concentrations able to increase at each stage, as with mercury.
- [14]
Land animals are also likely to accumulate PFAS present in their diet, but they are generally lower on the food chain since most are herbivores.
- [15]
Plants do not readily absorb long-chain PFAS, which tend to stay tightly bound to soil particles, but smaller PFAS molecules can be more mobile and are more easily taken up by plants.
- [16]
"This highlights an important fact: not all PFAS follow the same pathway in the environment."
- [17]
Average PFAS concentration in fish (about 1.9 ng/g) was roughly 2.5 times the top of the 0 to 0.75 ng/g range reported for dairy and plant-based foods.
Sources
1 independent publisher whose own reporting we read for this story.
- phys.orgFood testing reveals how diet can add to exposure to 'forever chemicals'
1 article · October 9, 2026
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