Department of Health advises against eating Lake Harriet largemouths, all Lake Elmo fish
Fishing on two popular Twin Cities lakes for the upcoming Minnesota fishing opener – and beyond – may have taken a hit after the Minnesota Department of Health advised Thursday, May 3 against eating fish from both lakes.
In its recommendation guidelines released Thursday, the MDH warned against eating all fish from Lake Elmo and largemouth bass from Lake Harriet in Minneapolis.
The MDH made the announcement in a press release regarding its new recommendations on how often to eat fish from certain Minnesota waters. The guidelines are updated as new monitoring data become available and are developed in collaboration with the Minnesota DNR and the Minnesota Pollution Control Agency, the release said.
This year’s guidance includes updated advice for six Twin Cities area lakes — Elmo, Harriet, Bde Maka Ska (formerly Calhoun), Lake of the Isles, Johanna and Twin – and the Mississippi River between the Ford Dam and the lock and dam at Hastings based on their levels of one type of contaminant known as perfluorooctane sulfonate (PFOS).
In the past, all of the aforementioned waters had levels of PFOS contamination that prompted a guidance limit of one meal per month for certain fish species, according to the release. The PFOS levels in the fish from five of the six lakes declined over the last decade, but the levels in fish from Washington County’s Lake Elmo remained high, the release continued.
MDH and MPCA officials say the most likely source of the elevated levels of PFOS in Lake Elmo is surface and groundwater contaminated by the former 3M disposal site in Oakdale, the release said, adding that the recent 3M settlement will allow further investigation and action as warranted to reduce the contamination. PFOS levels in Lake Harriet have been declining since the source of the PFOS – the nearby Douglas Corporation plating facility – was addressed starting in 2010. If PFOS levels in Lake Harriet continue to decline, the advice to avoid eating largemouth bass from the lake is likely to change as well.
MDH’s site-specific meal advice is meant to help limit exposure to contaminants like PCBs, mercury and PFOS by choosing fish lower in contaminants. The MDH also offers more general statewide safe-eating guidelines for avoiding exposure to contaminants in fish from all sources. Information on fish contamination in local lakes and waters also can be found on the DNR LakeFinder web app.
Based on updated scientific evidence and risk assessment for PFOS, the MDH last month changed the level at which it begins to advise not eating the fish at all – from 800 ng/g (nanograms per gram) to 200 ng/g – adding greater health protection. Applying this new threshold led to more restrictive fish consumption advice for some species in the six identified lakes, including not eating any fish from Elmo and no largemouths from Harriet.
In some studies, higher levels of PFOS in a person’s body have been associated with higher cholesterol, changes to liver function, changes in thyroid hormone levels and reduced immune response. Given the potential health effects of long-term exposure at elevated levels, MDH Assistant Commissioner Paul Allwood said the new guidance applies to everyone, not just higher risk populations.
“We recognize that some people may like to eat the fish they catch from these lakes, but this recommendation is prudent based on the available information,” Allwood in the release. “It’s important to note that our guidelines are based on long-term exposure, not the kind of short-term exposure you might have from a few meals.”
T.J. DeBates, the DNR’s east metro fisheries supervisor, said that even with the new recommendations, anglers should still consider fishing Elmo and Harriet on a catch-and-release basis. The open-water fishing season opens Saturday, May 12.
The guidance released Thursday focuses on fish from those six lakes and from the Mississippi River between the Ford Dam and the Hastings lock and dam because those were the bodies of water in which recent fish tissue data (from within the past five years) were available, the release said. This is because water contamination levels can drop quickly as contaminant sources are eliminated or mitigated, the release continued.
Over the next year, state agencies will collect and analyze fish from other waters to update the data and guidance, and in the coming months, MDH also will complete a more in-depth assessment of the potential benefits and risks of consuming fish containing PFOS at low levels, according to the release.