Mercury widespread in Chesapeake Bay headwaters fish

Release Date:

Bay Journal — By Jeremy Cox — Updated July 2, 2020

"Nearly half of all gamefish in freshwater lakes, streams and rivers in the Chesapeake Bay watershed may be unsafe to eat because of high levels of mercury, a new study suggests.

In the first study to examine mercury across a spectrum of fish in the six-state region, scientists found that the pollutant remains prevalent in the environment in its most toxic form despite years of declining mercury emissions.

The totals vary widely by location, a possible indication that local conditions are raising or lowering the risk of contamination, according to the research conducted by three U.S. Geological Survey scientists.

“Our goal here was to really do a first cut of what we saw across the landscape,” said Collin Eagles-Smith, a USGS research ecologist. “Hopefully, that can be a springboard for future studies to get a better sense at why.”

The study centers on the type of mercury that is most toxic to humans: methylmercury. The neurotoxin is formed when inorganic mercury interacts with certain bacteria. It is particularly harmful to fetuses and children, potentially leading to intellectual deficits and problems with motor skills.

In the Chesapeake Bay watershed, mercury is the main trigger for fish-consumption advisories. Coal-fired power plants and trash incinerators are the largest sources of the pollutant in the region, scientists say. Once released into the air, mercury can travel great distances before getting deposited into waterways through rainfall or as a gas.

The Chesapeake watershed’s mercury levels — with 45% of all fish in the study exceeding the consumption standard — are similar to those found in many parts of the country, the authors say. The findings underscore the importance of checking for public health advisories before eating any wild-caught fish, said James Willacker, the study’s lead author. . ."

Read the full article at the Bay Journal

 

« Return to Chesapeake Bay Activities — News