Risks from mercury in anadromous fish collected from Penobscot River, Maine

Area of Science:

• Environmental Science
• Ecotoxicology
• Fisheries Science

Background:

• Migratory fish are crucial components of aquatic ecosystems.
• Mercury contamination is a significant environmental concern impacting wildlife and human health.
• Anadromous fish populations in the Penobscot River are ecologically and culturally important.

Purpose of the Study:

• To quantify total mercury levels in six migratory fish species from the Penobscot River.
• To compare measured mercury concentrations against established human health and wildlife reference values.
• To assess potential risks associated with the consumption of these fish for both humans and wildlife.

Main Methods:

• Tissue and roe samples from alewife, American shad, blueback herring, rainbow smelt, striped bass, and sea lamprey were collected over two years.
• Total mercury concentrations were determined using established analytical methods.
• Data were compared to U.S. Environmental Protection Agency (EPA) reference doses and wildlife toxicity values.

Main Results:

• Mercury concentrations varied significantly among species, ranging from 4 microg/kg ww in American shad roe to 1040 microg/kg ww in sea lamprey.
• Sea lamprey exhibited the highest mercury levels in both sampling years.
• Consumption of rainbow smelt, striped bass, and sea lamprey posed potential risks to mink, otter, and eagle populations.

Conclusions:

• Current fish consumption advisories adequately protect human health from mercury, except for sea lamprey.
• Specific fish species, particularly sea lamprey, present ecological risks to top predators.
• The study provides critical data for future human health and wildlife risk assessments concerning anadromous fish consumption.