This project encompasses three major objectives: (1) To establish a screening mechanism for investigating pesticides and veterinary antibiotics, (2) To develop methods for detecting pesticide and veterinary antibiotic levels in environmental matrices, (3) To conduct an environmental survey and analyze the distribution of pesticides and veterinary antibiotics in Taiwanese river basins. The first objective involves the creation of a screening mechanism for pesticide investigation. The process for pesticide investigation referred from the principles outlined in the "Environmental Distribution of Chemical Substances Background Investigation Project in 2022," which incorporates screening criteria for the environmental distribution of pesticides outlined by the ministry of Agriculture. This process is designed to identify high risk pesticides for planning environmental distribution investigations. For veterinary antibiotics, target analytes are selected based on international lists of important veterinary antibiotics, domestic antibiotic usage, as well as those mentioned in related researches. The second objective is to establish analysis methods for detecting pesticide and veterinary antibiotic levels in alterative environmental media. Due to the absence of available standard testing methods for analyzing multiple pesticides or veterinary antibiotics in sediment or aquatic biological samples in Taiwan, the pesticide analysis referred to the methods provided by the Food and Drug Administration (FDA) and published reports. For veterinary antibiotics, the analytical methods referred to the U.S. Environmental Protection Agency (USEPA) and published techniques. Additionally, the analysis of water samples is modified based on the "Residue Pesticide Detection Method in Water" from Taiwan's Ministry of Environment and "Pharmaceuticals and Personal Care Products in Water, Soil, Sediment, and Biosolids by HPLC/MS/MS" from USEPA. Finally, it involves a survey of the distribution of pesticides and veterinary antibiotics in river basins. This includes the compilation of statistical data on agricultural land areas from the Department of Agriculture in Taiwan in 2021. Two river basins are selected in the central and western regions of Taiwan because of these districts have a high proportion of agricultural land, and they located in the major river basins from the Water Resources Agency of the Ministry of Economic Affairs. All sampling design, and sampling process are developed for river water, sediment, and aquatic organism. Throughout this project, an expert consultant committee on the " Screening Method in Pesticides and Veterinary Antibiotics " has been completed. This committee recommended an updated screening method to prioritize and adjust the sampling plan for designated pesticides and veterinary antibiotics in river investigations. So far, the analysis of pesticide and veterinary antibiotics measurements have been finished. Finally, the analytical results can be used to develop management strategies and recommendations, as well as laying the groundwork for future discussions on the presence of pesticide and veterinary antibiotic residues in the environment.

Environmental distribution, Pesticides, Veterinary antibiotics, River, Sediment, Fish