Occurrence, distribution and ecological risks of antibiotics and pesticides in coastal waters around Liaodong Peninsula, China

Highlights: • 13 antibiotics and 15 pesticides were screened in coastal waters of China. • Simazine, atrazine and sulfamethoxazole were found to be predominant pollutants. • The pollution level in the Bohai Sea was higher than that in the Yellow Sea. • Atrazine and acetochlor showed relatively higher risks to aquatic organisms. -- Abstract: Mariculture activities and river inputs can lead to pollution of micropollutants (e.g., antibiotics and pesticides) in coastal seawater which is the base of the most dynamic ecosystems due to its hosting some of the highest biodiversity and biological production in the world. It is thus of importance to investigate the occurrence and risks of organic micropollutants in coastal waters. In this study, 13 antibiotics and 15 pesticides were screened in coastal waters around the Liaodong Peninsula, China. Among the targets, thirteen were detected with concentrations up to 64.8 ng L⁻¹. Simazine, atrazine and triadimenol were found to be the predominant pesticides with detection frequencies of 100%, and sulfamethoxazole was the predominant antibiotic with a detection frequency of 62.5%. The total level of the pollutants in the Bohai Sea was generally higher than that in the Yellow Sea, and a seaward decreasing trend of the pollutants was observed. Terrestrial inputs and mariculture were distinguished as main pollution sources by principal component analysis. Finally, ecological risk quotients were calculated and atrazine and acetochlor showed relatively higher risks to aquatic organisms.