Heavy metal bioaccumulation in Etroplus suratensis residing in inland rivers and Amblygaster sirm in marine habitats in Sri Lanka: A comparative study

Abstract

Inland and marine fish are primary protein sources of the Sri Lankan diet. Prolonged consumption of contaminated fish can cause critical health implications such as chronic kidney disease (CKDu). This study investigates the bioaccumulation of heavy metals in edible fish from inland rivers and coastal regions using Etroplus suratensis residing in inland rivers and Amblygaster sirm in marine habitats in Sri Lanka for the analysis. Inland fish samples were collected from Nikawewa and Mahakandarawa tanks in Kurunagala and Anuradhapura districts, respectively, while marine fish samples were collected from the coastal region near Trincomalee harbour. The analysis of heavy metal/ metalloid (i.e., Pb, Cr, As, Cd, and Ni) contents in fish samples revealed that muscle tissues of inland fish samples had significantly higher levels of Pb and Cr, exceeding the Maximum Permissible Limits (MPL). In contrast, marine fish exhibited negligible amounts of heavy metals across all tissues. Health risk assessments indicated that the Estimated Daily Intake (EDI), Total Hazard Quotient (THQ), and Carcinogenic Risk (CR) values for Pb and Cr in inland fish were significantly higher than those in marine fish, suggesting potential health risks. One-way ANOVA and Tukey's pairwise comparisons confirmed significant (p < 0.05) geographical and tissue-specific variations in heavy metal concentrations. Inland regions showed higher contamination levels than coastal regions. Gut tissues generally had the highest concentrations of heavy metals, followed by muscle, gill, and liver tissues. These findings underscore that the inland fish samples from the studied regions may pose adverse health effects, emphasizing the need for continuous monitoring and regulation to mitigate heavy metal contamination and safeguard human health.