Contamination and risk profiles of triclosan and triclocarban in sediments from a less urbanized region in China

Triclosan and triclocarban are priority environmental contaminants of increasing concern to environmental health. After application, the chemicals enter the aquatic environment and easily distribute in bed sediment due to their hydrophobicity, and thus pose potential ecological risks. This study investigated the distribution and risks of triclosan and triclocarban in the sediment environment of a less urbanized region in South China. The sampling sites with high levels of triclosan and triclocarban were found to locate in the tributaries. When compared to other monitoring results obtained from more densely populated regions, the residues of triclosan and triclocarban in the investigated region were low, suggesting that these two chemicals conservation in sediment is related to anthropic activities. The results of risk quotients showed that high risks to aquatic organisms were posed by triclosan residues in sediment, while the risks to benthic organisms were quite low. Triclocarban residues in sediment posed minimal to medium risks to aquatic and benthic organisms. In summary, using either of the calculation methods of risk quotients, medium risks posed by the antimicrobials can be found in certain sampling sites with low population densities. The results may be useful in the development of evidence-based policies for the government.