Trace metal contamination and health risk assessment in fish from Lake Tana and Lake Hayqe, Ethiopia

Abstract

Trace metal contamination in aquatic ecosystems poses a significant environmental and public health challenge, especially in developing countries like Ethiopia. This study evaluates the concentrations, potential sources, and health risks of trace elements in Lakes Tana and Hayqe, focusing on the implications for adult fish consumers. Forty fish samples were collected, cleaned, and wet-digested using standard protocols, and trace element concentrations were determined using Flame Atomic Absorption Spectrophotometry (FAAS). The findings revealed that in Lake Tana, the mean concentrations (mg/kg) of Mn (22–27), Cd (6.8–15), Pb (4.8–7.8), and Cr (11) exceeded the permissible limits set by regulatory bodies for safe consumption, while Fe (15–57), Cu (4.7–6.1), and Zn (20–25) were within acceptable limits. Similarly, in Lake Hayqe, the mean concentrations of Zn (43–48), Cd (8.5–19), Cr (0.9–12), Pb (7.0–12), and Mn (35) were above satisfactory limits, except for Fe (86–90) and Cu (4.7–7.6), which were within safe thresholds. The non-cancer risks were less than 1, while the cancer risks were within the tolerable intake values of 10⁻⁴ - 10⁻⁶, indicating less health risk for fish consumers. Statistical analyses highlighted interrelationships among trace elements and identified contamination sources, underscoring anthropogenic activities as significant contributors. These results call for comprehensive monitoring and stringent regulatory measures to curb trace metal pollution and safeguard public health. Further research should explore the broader ecological consequences of metal contamination and investigate emerging pollutants in aquatic ecosystems.