Title: Tiered probabilistic assessment of organohalogen compounds in the Han River and Danjiangkou Reservoir, central China
Authors: Hongwei Sun, John P. Giesy, Xiaowei Jin, Jun Wang*
Affiliations: 1. Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
2. Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China
3. Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
4. China National Environmental Monitoring Center, Beijing 100012, China
Year: 2017
Journal: Science of the Total Environment
Link: http://www.sciencedirect.com/science/article/pii/S0048969717302115
Abstract: Occurrence of organohalogen contaminants (OCs) including 12 organochlorine pesticides (OCPs), 7 polychlorinated biphenyl congeners (PCBs) and 7 polybrominated diphenyl ethers (PBDEs) were investigated in the Han River, which is the largest tributary of the Yangtze River, and Danjiangkou Reservoir, the source of water for China's South-to-North Water Diversion Project. OCPs were found to be dominant in water, with concentrations of 0.14–11 and 2.9–59 ng L-1 during winter and summer, respectively. In sediment, OCPs were also predominant contaminants during summer (5.0–1.7 × 102 ng g-1), whereas during winter PCBs (4.3–2.3 × 102 ng g-1) were dominant. Concentrations of OCs observed during this study were generally less or comparable to those from other locations in the world. Concentrations of OCPs were significantly greater in lower reaches of the Han River, during winter. This observation might be due to proximity of this location to more developed areas. Distributions of OCs between water and sediment were not at steady state except for PBDEs during winter. This disequilibrium is likely due to continuing inputs of pollutants. A tiered assessment of risks to aquatic organisms was conducted for OCs. Initially species sensitivity distributions (SSD) were employed to determine predicted no effect concentration (PNEC), followed by evaluation based on hazard quotients (HQ). In subsequent tiers, a probabilistic approach was used to develop joint probability distributions, where species sensitivity distributions were compared to distributions of measured concentrations of OCs. Consistent results were obtained by use of all methods, which suggested endosulfans and heptachlors could pose risk to local aquatic organisms. Furthermore, heptachlors and PCBs might also cause potential adverse effect to health of humans through consumption of water.
