Antagonistic Effects, Sources, and Distribution of Selenium and Toxic Metals in Fish from Selenium-Rich and High Cadmium Areas, Dashan Region, China

The Gongxin River is one of the main rivers in the Dashan Region of Anhui Province in China, which is a Se-rich and high-Cd area, but no research has focused on the concentration, source, antagonism, and health risks of Se and TMs in fish. In this study, 120 fish samples (14 species), 24 sediment samples, and 24 water samples were collected to investigate the antagonistic effects, sources, and health risks of TMs and Se in fish from a typical selenium-rich and high cadmium region. Zn and Se in fish from the Gongxin River were higher than in the background, which might be attributed to the different feeding habits of different fish species. The apparent antagonism between Se and Cu, Pb, and Cd was explored, and the results showed that 30%, 75%, and 100% of the Se/Cu, Se/Pb, and Se/Cd ratios were greater than one, indicating that Cu, Pb, and Cd in fish might be combined with or detoxicated by Se. The source analysis of the elements showed that the geological background was the source of TMs and Se in fish samples. The amounts of Se and TMs were all within China’s acceptable level guidelines, signifying no harm to citizens from eating fish.