Analysis of heavy metals in Ictalurus punctatus (channel catfish), Perca flavescens (yellow perch), and Aplodinotus grunniens (freshwater drum) in a Coastal Lake Michigan Watershed

Abstract

Studies on metals in Great Lakes fish have focused typically on mercury (Hg), with less attention on other contaminants. Few studies exist on fish from drowned river mouths supplying the Great Lakes. This paper reports on metals in 3 common species, Ictalurus punctatus (channel catfish), Perca flavescens (yellow perch), and Aplodinotus grunniens (freshwater drum, a.k.a. sheep head) sampled from a coastal lake in West Michigan, USA. 135 fish were taken with pole and line methods from 6 different locations from July 2019–July 2021. Flank tissues were processed and analyzed by ICP-OES techniques for antimony (Sb), arsenic (As), barium (Ba), cadmium (Cd), cerium (Ce), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), magnesium (Mg), manganese (Mn), nickel (Ni), selenium (Se), and zinc (Zn). Eight metals detected at quantifiable levels were Ba, Cr, Cu, Fe, Mg, Mn, Se, and Zn. Mg levels were the highest for all sites and all fish, with averages ranging from 300-1400 ppm (mg/kg of wet tissue). Zn concentrations ranged 11–21 ppm, Fe 4–14 ppm, Se 1–5 ppm, Mn about 0.4–1 ppm, and Cu below 1 ppm. Cr was only quantifiable in 34 % of the fish at <1 ppm, and Ba was detectable in 20 % of the fish, from approximately 0.1 to 4 ppm. Results were examined for statistically-significant differences between species and sites. Comparison of 3 species from one site showed sheep head had lower levels of all metals, except Fe, which were indistinguishable from perch. Cu was higher in catfish than perch, and Mn and Ba concentrations were lower in sheep head by 10× and 100×, respectively, when compared to other species. Zn, Mg, Fe, and Mn concentrations were different in perch from different sites; and, sheep head contained different concentrations of Se, Zn, Fe, Mn, Cr, Cu, and Ba between sites.