Occurrence and risk assessment of triclosan in freshwater lakes in the middle Yangtze River basin (Wuhan, Central China)

ABSTRACT

Triclosan (TCS) is an endocrine disrupting chemical which is commonly used as a disinfectant in pharmaceuticals and personal care products (PPCP's). Since early 2020, the worldwide outbreak of COVID-19 has increased the use of PPCP's, so the occurrence and impact of TCS on freshwater lakes should be considered. However, little attention has been given to the effect of TCS on freshwater lakes in China. This study is the first attempt at a risk assessment focusing on the temporal and spatial occurrence of TCS in freshwater lakes in the middle Yangtze River basin. The surface water and sediments of Donghu Lake and Liangzi Lake (Wuhan, Central China) were collected from October 2020 to August 2021. The maximum concentrations of TCS were 466 ng/L and 239 ng/L in surface water, 71 ng/g and 25 ng/g (dry weight) in sediments of Donghu Lake and Liangzi Lake, respectively. Significant temporal and spatial differences of TCS were observed within and between the lakes, with the highest concentrations measured in winter. Furthermore, higher concentrations of TCS were observed in areas that are more impacted by human activities. There was a significant positive correlation between TCS and nitrogen in the surface water. A risk assessment using the risk quotient (RQ) method showed that a potentially high risk (RQ > 1) was found only in surface waters from Donghu Lake, and that the sediments posed a lower risk than the surface waters. These results provide timely data on the temporal and spatial occurrence of TCS in freshwater lakes in China following the outbreak of COVID-19 and demonstrate a possible high risk of exposure to TCS for aquatic biota.