Bioaccumulation Of Polybrominated Diphenyl Ethers (PBDEs) In Tree Bark Andheavy Metals In Tree Ringsat E-waste Recycling Area

Wenling, located in Taizhou, Zhejiang province, has been involved in e-waste recycling activities for several decades. In this study, tree bark and the corresponding air samples were collected at Yanggong’ao, Wenqiaozhen, Danyashan and Changyudongtian to investigate the relationship between the polybrominated diphenyl ethers (PBDEs) concentrations in bark and those in air, thesignificant correlation(r2=0.64-0.99; P<0.05) for individual PBDE congeners indicated that atmospheric PBDEs were the principle source for the accumulation of PBDEs in the barks. What’s more, the log KBA (bark-air partition coefficient) of individual PBDE congeners at the four sites ranged from5.69to6.79which were in good agreement with previous studies. Furthermore, the different barks were sampled to discuss the influence of the tree species, trunk circumference and bark thickness on the accumulation processes of PBDEs from air into the bark. The results of different PBDE concentrations indicated that barks with a thickness of0to3mm collected from weeping willow, Camphor tree and Masson pine, the trunk circumferences of which were100to150cm, were better PBDEs passive samplers. Finally, the PBDE concentrations in camphor tree barkssampled at different sites in Wenling were from26.53-1317.68ng/g dw (mean587.38ng/g dw). The high PBDEs levels in Wenling reflected that crude household workshops contributed heavy pollution of PBDEs to the neighboring environment.The Dendroanalysis was applied to investigate the historical dynamics of heavy metal concentrations caused by e-waste recycling activities in Wenling. Heavy metals (Pb、Cu、Cr、 Ni、Sn and Sb) in tree rings collected from Yanggong’ao, Mukengcun, Tongshancun (e-waste recycling areas) and Changyudongtian (the control area) were determined. The results showed that the heavy metal concentrations in tree rings collected from e-waste recycling areas were significant higher than these collected from the control area. It was also found that the heavy metal concentrations in tree rings had been obviously rising since1995and the increment speed in tree rings in e-waste recycling areas were much higher than these in the control area. It was suggested that e-waste recycling activities might be the main factor leading to the heavy metal pollution in Wenling.