From the San Francisco Estuary Institute:
Ten species of popular fish to eat from San Francisco Bay may contain dangerous levels of “forever chemicals”—but where they’re caught in the Bay can make a big difference.
A team of scientists with the San Francisco Estuary Institute (SFEI) tested fish samples collected throughout the Bay since 2009 for a notorious group of chemicals called PFAS, or “forever chemicals”, which cause rampant harm in humans from reproductive issues to cancer. The research detected 20 types of these “forever chemicals” in total, including one never documented before in marine fish.
“It’s been really important work because we don’t have a lot of PFAS tissue data throughout the state,” says Wesley Smith, a senior toxicologist with the California Office of Environmental Health Hazard Assessment. “It’s really helping us think about how we develop our risk assessment for PFAS in fish.”
California doesn’t yet have health guidelines for PFAS in fish. But Massachusetts’ guidelines, the strictest in the nation, suggest that fewer than one in five of the fish samples could safely be eaten daily. A third of the samples had too much PFAS to eat even once a week.
“We know already that [PFAS are] impacting all of us,” says Miguel Méndez, an environmental scientist with SFEI and the lead author of the new research. “But we also know that there’s a lot of communities in the Bay that fish, and a lot of these communities tend to be underrepresented and more marginalized in the Bay. And so we know that those communities are being impacted more.”
LaDonna Williams is a leader in one such community in Richmond, near where San Francisco Bay bottlenecks into the entryway of the Sacramento-San Joaquin Delta. She used to eat fish caught near her home “for breakfast, lunch, and dinner.”
“Dinner would be either fried fish, baked fish, or we stewed it,” she says. “My family would dry fish and use it as seasonings for gumbo.”
Most of the recent samples from fish caught in Williams’ neck of the Bay have low enough levels of a common PFAS to safely eat once a week, based on Massachusetts’ recommended limit. But further south in the San Francisco Bay, the results were more concerning: four in five samples collected exceeded that same once-a-week threshold.
Smith also notes that many people eat more of a fish than just the fillet, especially in Bay Area cultural communities that often fish from the Bay. Most studies, including this one, focus on information testing the fillets for contamination. But Smith says that PFAS might concentrate even more in the skin, eyes, or other organs, exposing people who enjoy eating the whole fish to even higher risk.
Even so, he emphasizes how important this research is to move California towards recommending PFAS thresholds for safe fish consumption.
“There’s the theoretical science,” says Smith, but “it’s so important to actually have monitoring done.”
Williams agrees. She now eats less fresh-caught fish, but still advocates for more research to protect her fellow fishers from the dangers of home-cooked fish served with a side of contaminants.
“We need some real in-depth information,” she says, “so that we really can come up with some solutions.”
This project was funded by the Regional Monitoring Program for Water Quality in San Francisco Bay and the San Francisco Bay Regional Water Quality Control Board.
READ THE STUDY: Spatial Trends and Health Risks of Per- and Polyfluoroalkyl Substances in San Francisco Bay Fish from 2009 to 2019, ES&T Water
