This project collected sediment samples from ten Taiwanese rivers (i.e. Keelung River, Toucian River, Keya River, Dajia River, Jhuoshuei River, Beigang River, Puzih River, Shincheng River, Erren River and Siouguluan River) to determine concentrations of toxic substances such as mirex, hexabromocyclododecane (HBCD), nonylphenol (NP), bisphenol A (BPA), phthalate esters, polybrominated diphenyl ethers (PBDEs), organic and inorganic arsenic. The 2,160 analyzed data were completed. According to the past investigation, the concentrations of mirex in sediments of 20 Taiwanese major rivers were relatively low, but it is necessary to complete analysis of mirex in sediments of 30 major rivers for establishing the backgound data of mirex (belonging to persistant organic pollutants, POPs) in Taiwan. The concentrations of HBCD in sediments of 30 major rivers were relatively low, indicating the investigation on this compound could be stopped for planing investigation on the other POPs. The concentrations of NP and BPA in sediments of 30 rivers mostly decreased with time. However, the concentrations of NP and BPA in sediments of some rivers were relatively high or decreased in the past but increased in this year. The recent 3-year survey showed that the average DEHP concentrations in sediments from Danshuei River, Sindian River, Keelung River, Nankan River, Yanshuei River, Dian Bao River, Linbien River were still higher than 1.97 mg/kg (the lower limit of sediment quality). The two-stage long-term survey on PBDEs in the river environment showed that there was no decreasing trend on the concentrations of PBDEs in the river sediments. It is suggested that environmental monitoring of PBDEs should be continued and a review of control policies is needed. The concentrations of organic and inorganic arsenic were much lower than the lower limit of sediment quality. The future work on the environmental survey of toxic substances distribution was proposed and 22 priority toxic substances were suggested for environmental survey. “The database searching website for environmental distribution of toxic substances” was maintained and the information on the section of popular science was increased. “The handbook of investigation achievements on the toxic substances distribution in Taiwan, version 2016” was published as an e-book.

Toxic substances, Environmental distribution, River Sediment