Heavy metal pollution characteristics and health risk assessment of fish in Dongjiang River

The aim of this study was to investigate the contamination status of heavy metals in fish in the Dongjiang River Basin. 34 points of major fish (Hemiculter, pangasius, mahi-mahi, Mozambique tilapia, Qi's tilapia, and fine-scale channel catfish) were collected from the Dongjiang River Basin in 2021. The main experimental methods were the removal of liver parts from fish and microwave digestion followed by LC-ICP-MS measurement of Zn, Cu, As, Cd, Mn, Cr and Ni using a high performance liquid phase inductively coupled plasma mass spectrometer. The test results showed that the levels of Zn, Cu, As, Cd, Mn, Cr and Ni in fish from the entire Dongjiang basin in 2021 ranged from nd~49.99, nd~1.82, nd~0.09, nd~0.32, nd~43.92, 0.47~1.72 and nd~1.14 mg-kg-1 respectively, with mean values of 22.74, 1.01, 0.03, 0.05, 20.6, 0.97 and 0.22 mg-kg-1, respectively, which did not exceed the limits in the National Food Safety Standards for Contaminants in Food. The results of the single-factor pollution index and the composite pollution index also showed that the heavy metal contamination level of the fine-scale catfish was light and the other five fish species were non-polluting. The results of the single and multiple heavy metal composite hazard factors showed that the TTHQ values of all six fish species were less than 1, indicating that there was no potential health risk to the exposed population for these six fish species in the Dongjiang basin.