This study investigated the occurrence and distribution of pesticides in surface water (lakes, major rivers and tributaries) and potential discharge sources (fish ponds, livestock and poultry farms, and sewage treatment plants) in Wujin District (northwest of Taihu Lake), Jiangsu province, China. An analytical liquid chromatography-tandem mass spectrometry method was developed for 38 pesticides, which was applied in the monitoring of 240 surface water samples and 76 potential discharge source samples. Eleven insecticides and five fungicides with temporal and spatial variation were detected in surface water. The total pesticide concentrations in surface water in different seasons were as follows: March > August > June > November. The two most polluting and widespread pesticides were carbendazim (maximum concentration 508 ng L −1 , detection rate 100%) and imidacloprid (maximum concentration 438 ng L −1 , detection rate 88%). Gehu Lake (S46) and Sanshangang River (S12) were seriously polluted water bodies. Seven insecticides and four fungicides were detected in the potential discharge sources; and their composition changed significantly with the seasons. The concentrations of detected organophosphorus pesticides and neonicotinoids ( e.g. acetamiprid in March and dichlorvos in November) in a few non-agricultural planting sources were far greater than those detected in surface water, and hence a few fish ponds, livestock and poultry farms, and sewage treatment plants might be the potential discharge sources of pesticides in the surrounding surface water. The estimated input flux of the studied pesticides from upstream rivers to Taihu Lake was 141.95 kg a −1 . Furthermore, more attention should be paid to the medium or high aquatic ecotoxicological risk presented by the levels of organophosphorus pesticides, carbamates, and benzimidazoles.
Sediment adsorption is one of the main fates of antibiotics in aquatic environments. However, few studies have compared the physicochemical properties of sediments from the same aquatic ecosystem but at different locations and correlated them with antibiotic adsorption efficiency. To predict the adsorption of antibiotics in water–sediment systems more accurately, this study conducted experiments with tetracycline (TC) and oxytetracycline (OTC) in tetracyclines, ciprofloxacin (CIP) in fluoroquinolones, and roxithromycin (ROX) in macrolides. Sediments from different locations in Lake Taihu, China, were collected to determine the adsorption properties of CIP, TC, OTC, and ROX. Moreover, the physicochemical properties of the sediments were measured and the correlation between these properties and antibiotic adsorption were discussed to establish a model for predicting adsorption parameter K d . The antibiotic adsorption performance of sediments was high in heavily polluted and grassy areas but poor in estuarine areas of the lake, suggesting that adsorption effectiveness was affected by the physicochemical properties of sediments. Based on the established model, the specific surface area, organic carbon , and cation exchange capacity played the most significant roles. The study further determined that the predicted and actual values showed a good linear fitting relationship. Therefore, the model effectively predicted the antibiotic adsorption performance of different sediments and provided recommendations for the environmental trend and risk assessment of antibiotics.
危险品化学品经营许可证（带存储）