The effect of mangrove reforestation on the accumulation of PCBs in sediment from different habitats in Guangdong, China

The distribution of PCB homologues in mangrove forests and mud flat were quite different, which indicated that mud flat preferred to accumulate the low-and moderately-chlorinated biphenyls while the mangrove forests accumulated the high-chlorinated more easily. However, obvious differences were found in the sites in Shenzhen, probably because the mangrove forests were established just two years ago in Shenzhen. In this study a direct correlation between PCBs concentrations and organic carbon contents was weak correlation. This may be caused by other accumulation factors such as grain size and the different accumulated patterns of PCBs for mangrove sediments and mud flat. [Display omitted] ► We investigate the influence of mangrove reforestation on the accumulation of PCBs. ► Both natural and the restored native mangrove forests rehabilitate PCBs pollution. ► The exotic species Sonneratia apetala is not recommended here for its aggravation of PCBs. To investigate the influence of mangrove reforestation on the accumulation of PCBs, the concentrations and homologue patterns of polychlorinated biphenyls in surface sediments from different mangrove forests and their adjacent mud flats in Guangdong Province were determined. The total PCB concentrations in the sediments ranged from 3.03 to 46.62ngg−1 (dry weight). Differences in the accumulation and distribution of PCBs were found between the mangrove sites and the mud flats. Furthermore, the natural forests and restored mangrove forests of native species showed slight PCB contamination, whereas the exotic species Sonneratia apetala exacerbated the PCB pollution at certain sites. It was suggested that the native mangrove species Kandelia candel and Aegiceras corniculatum could represent good choices for the phytoremediation of PCB contamination.