Effects of diuron transformed chemicals on life history traits of the copepod Tigriopus koreanus

Diuron is commonly used as a booster biocide in antifouling paints to prevent adherence of aquatic organisms to the hulls of ships. Under aerobic conditions, bacteria can metabolize diuron to 3,4-dichloroaniline and 4,5-dichlorocatechol, which may induce adverse effects on aquatic organisms. We investigated the acute and chronic effects of these three chemicals on the marine copepod Tigriopus koreanus. In the acute toxicity test, diuron was the most toxic of the three chemicals. In the chronic toxicity test, developmental time was increased by diuron and 3,4-DCA, but was reduced by 4,5-DCC. Fecundity was increased by diuron but reduced by 3,4-DCA. Exposure to 4,5-DCC resulted in a female-biased sex ratio. Post-exposure expression of detoxification, antioxidant, and DNA-repair genes differed depending on the chemical and sex. These results suggest that not only diuron but also its decomposed chemicals may affect marine copepods, and decomposed products of booster biocides should be evaluated for a comprehensive environmental toxicity assessment of decomposable organic pollutants.