Biomonitoring of Toxic Metals and Metalloids in Hair and Nails of Fishermen from Lake Hawassa, Ethiopia.

Abstract

Contamination of aquatic ecosystems by toxic metals and metalloids poses potential health risks to fishing communities with high fish consumption. This study assessed arsenic (As), mercury (Hg), chromium (Cr), and copper (Cu) concentrations in paired hair and nail samples from 50 fishermen on Lake Hawassa, Ethiopia, using MP-AES. Descriptive statistics, Wilcoxon signed-rank tests, correlation analyses, and multiple linear regression were applied to evaluate elemental concentrations, relationships between biomarkers, and the influence of age and fishing experience. Nails generally showed higher elemental levels than hair. Median concentrations in hair and nails were 0.15 and 0.42 µg/g for As, 0.18 and 0.35 µg/g for Hg, 0.43 and 0.70 µg/g for Cr, and 8.73 and 7.73 µg/g for Cu, respectively. Significant differences between biomarkers were found for As (p = 0.029) and Hg (p = 0.038), but not for Cr and Cu. Elevated levels above reference values were more frequent in nails, especially for As (36%), Hg (30%), and Cr (30%). Hair and nail concentrations correlated positively for As (R²=0.15, p = 0.005) and Hg (R²=0.22, p < 0.001). Age and fishing experience were not major determinants, though fishing experience negatively correlated with hair Cr (β=-0.547, p = 0.004), and age with nail Cu (β=-0.511, p = 0.034). The findings confirm measurable exposure to toxic elements and suggest nails may be a more sensitive long-term biomarker than hair. This establishes baseline data and underscores the need for ongoing environmental and health surveillance in the region.