Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in water pose a great threat to ecosystem and human health due to the persistent, toxic and bioaccumulative nature. South China, as one of the rapid economically developed regions and the most densely populated region in China, experienced severe heavy metals pollution and organic contamination. Therefore, it’s critical to understand the levels of PCBs and PBDEs in the water resources for water management and human health in South China. 

Dr. YANG Yuyi, under the supervision of Prof. WANG Jun from Wuhan Botanical Garden, investigated the pollution levels, distribution and risk assessment of seventeen PCBs and nine PBDEs detected from nine important water sources in South China using gas chromatograph analysis.  

The solid-phase extraction and the Chromatographic analysis revealed that the concentrations of total PCBs and PBDEs in the water sources, South China ranged from 0.93 to 13.07 ng L^-1 and not detected (nd) to 7.87 ng L^-1, respectively. 

The patterns of PCBs and PBDEs homologues indicated that the historical use of Aroclors 1248, 1254 and 1260, and the commercial products of PBDEs were the main source of contamination in South China. In addition, self-organizing map neural network (SOM), an effective tool to classify the metal pollution, was used to classify the nine water sources into three clusters.

The cancer risks of PCBs and PBDEs were all below 10^-6 (the accepted level of cancer risk for water pollutants was in 10^-4-10^-6), revealing the PCBs and PBDEs in water source, South China had no harm to human health. 

This project was supported in part by Natural Science Foundation of Hubei Province of China, Open Funding Project of the Key Laboratory of Aquatic Botany and Watershed Ecology, Chinese Academy of Sciences, and the Hundred Talents Program of the Chinese Academy of Sciences. Results were published in Ecotoxicology and Environmental Safety entitled “Occurrence, distribution and risk assessment of polychlorinated biphenyls and polybrominated diphenyl ethers in nine water sources”. 

The pattern of PCB congeners in nine water sources, South China (Image by Dr. YANG Yuyi)