This project collected sediment samples from ten Taiwanese rivers (i.e. Danshuei River, Dahan River , Sindian River, Bajhang River, Jishuei River, Zengwun River, Gaoping River, Linbien River, Hualien River, and Beinan River) to determine concentrations of toxic substances such as endosulfan, hexabromocyclododecane (HBCD), nonylphenol (NP), bisphenol A (BPA), phthalate esters, polybrominated diphenyl ethers (PBDEs), organic and inorganic arsenic. The investigation was also conducted for the rivers whose sediment contain high concentrations of toxic substances, such as NP in Keya River, HBCD in Donggang River, Lanyang River, and Shincheng River, PBDE in Keelung River and Keya River. A total of 1,896 analyzed data was collected. The results showed the concentrations of endosulfan in sediments were ranged from 0.01~0.2 ug/kg, which were similar to the measurements from other countries. The concentrations of HBCD were near 2 ug/kg, which were lower than the measurements from other countries. The concentrations of NP and BPA in most sediments were lower than the past measurements, but NP concentrations in Danshuei River still had the highest levels among 30 Taiwanese major rivers. The concentrations of di(2-ethylhexyl) phthalate (DEHP) in the river sediments were decreased. The average DEHP concentrations in sediments from Danshuei River, Sindian River, Nankan River, Yanshuei River, Dian Bao River, Linbien River were still higher than 1.97 mg/kg (the lower limit of sediment quality in action, which means need to increase the monitoring frequency). The concentrations of PBDEs in sediments from Nankan River and the whole Danshuei River were the highest among 30 rivers. The concentrations of As3+ (arsenic) were much lower than the lower limit of sediment quality in action, which means need to increase the monitoring frequency. 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 improved in searching functions. “The handbook of investigation achievements on the toxic substances distribution in Taiwan, version 2015” was edited and published as an e-book.

Toxic substances, Environmental distribution, River Sediment