WASHINGTON, July 14 (UPI) — Amounts of mercury in a popular game fish species in Lake Erie are increasing after thirty years of declining levels, U.S. researchers say.
A study of 5,807 fish samples collected from the Great Lakes between the 1970s and 2007 showed a steady decline in mercury levels for most of that period in the upper lakes of Superior and Huron, but in recent years mercury levels have risen in Lake Erie walleye, a release by the American Chemical Society said Wednesday.
Government regulations and improved emissions control technologies have greatly reduced environmental mercury emissions, but their impact on mercury levels in Great Lakes fish is unclear, the study said.
The Great Lakes is the largest group of freshwater lakes in the world, and their $7 billion fishing industry is of significant economic importance to both the United States and Canada.
There are concerns high levels of mercury in fish can potentially cause adverse health effects in people, the study notes.
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