RISK OF MERCURY CONTAMINATION TO THE HEALTH OF FISH IN THE SOUTH CENTRAL UNITED STATES
Methyl mercury (MeHg) is a toxic heavy metal that contaminates all aquatic systems and can pose a risk to the health of fish. In this study, we examined how Hg deposition, fish trophic position and fish length affected MeHg risk to fish in 14 ecoregions of 6 states of the south central U.S. We used the National Descriptive Model for Mercury in Fish to estimate average MeHg concentrations of five size categories of bluegill (Lepomis macrochirus), a low trophic position invertivore, and largemouth bass (Micropterus salmoides), a high trophic position piscivore, at 728 sampling sites. We determined the percentage of sites where estimated MeHg concentrations in fish exceeded risk thresholds associated with potential 1) biochemical effects, 2) reproductive and behavioral effects and 3) growth effects. The percentage of sites where fish MeHg concentrations exceeded at least one risk threshold increased with Hg deposition in ecoregions, fish trophic position and fish length. Large-sized largemouth bass in ecoregions with high Hg deposition were at the greatest risk. Our results indicate that MeHg contamination in the south-central U.S. could negatively impact largemouth bass and perhaps other large, piscivorous fish species.
Ray Drenner (Co-Presenter/Co-Author), Texas Christian University, firstname.lastname@example.org;
Matthew Chumchal (Primary Presenter/Author), Texas Christian University, email@example.com;
Madeline Hannappel (Co-Presenter/Co-Author), Texas Christian University, firstname.lastname@example.org;
Spencer Weinstein (Co-Presenter/Co-Author), Texas Christian University, email@example.com;
Chris Gerstle (Co-Presenter/Co-Author), Texas Christian University, firstname.lastname@example.org;