Widely used in industrial products, Polychlorinated Biphenyls (PCBs) and PolybrominatedDiphenyl Ethers (PBDEs) are characterized by persistence, bioaccumulation and potential toxicity. PCBs and PBDEs can accumulate and remain in the sediment, which may pose an unacceptable risk to sediment-dwelling organisms. These organisms tend to accumulate organic pollutants and transfer them along the food chain, causing adverse health effects to wildlife and humans. 

As the second largest urban lake in China, East Lake is located in the northeast of Wuhan. It was very important for fishery production and the life of local residents for aquatic sport and recreation. However, with the rapid industrialization and urbanization, environmental pollution around the lake has been constantly increasing during the past three decades.  

In order to evaluate the current contamination situation with selected PCBs and PBDEs in surface sediment of the East Lake, Prof. WANG Jun and his research team from Wuhan Botanical Garden analyzed the spatial distribution, seasonal variations, identified their possible sources and assessed the potential eco-toxicological risks of these compounds collected in winter 2012 and summer 2013. 

Qualitative and quantitative analysis of PCBs and PBDEs was carried out with an Agilent 7890A gas chromatograph equipped with an electron capture detector (GC-ECD) and a Model 5975 mass spectrometer (MS) using electron-ionization ion source (EI) in the selected ion monitoring mode.

Results showed that the total PCB concentration ranged from not detected to 107.1 ng g^-1dw with PCB-28, 101 and 180 as the dominant congeners in both winter and summer. The total PBDE concentrations ranged from 9.7 to 151.3 ng g^-1dw, with the dominant congeners following the order: BDE-28> BDE-99> BDE-47. 

The concentrations of PCBs in the sediment samples collected in summer were almost two times greater than those in winter, which may be caused by the contaminations input, originated from urban and land runoff generated in the rainy period. However, the concentrations of PBDEs, which probably originated from historical usage of penta-BDE mixtures, did not show much seasonal variations. 

In comparison to published guidelines and the hazard quotient approach, potential eco-toxicological risk of PCBs was low, while potential eco-toxicological risk from PBDEs was moderate in the East Lake, China. 

This research was published in Ecotoxicology entitled “Concentrations and risk assessment of polychlorinated biphenyls and polybrominated diphenyl ethers in surface sediments from the East Lake, China”  

Seasonal variations of total PCBs (a) and PBDEs (b) in surface sediment from the East Lake (Image by YUN Xiaoyan)