Tracing the sources and microbial degradation of PCBs in field sediments by a multiple-line-of-evidence approach including compound-specific stable isotope analysis

Abstract Comprehensive monitoring is crucial for tracing micropollutants in the natural environment. To better evaluate the sources and natural attenuation of polychlorinated biphenyls (PCBs), three composite sediment cores were sampled from a closed pond near e-waste recycling plants, and a multiple-line-of-evidence approach (MLEA) including quantification, enantiomer analysis, microbial community profiling, and compound-specific isotope analysis (CSIA) was used to investigate the fate of PCBs in sediment cores. The difference in the maximum PCB concentrations and associated depths between sites 1/2 and 3 and the corresponding significant (p   1‰) of PCB congeners were observed, confirming that in situ degradation occurred in the sediment cores. The progressive enrichment in 13C with increasing core depth suggested strengthened microbial degradation of the residual congener pools. The results of this study suggested that MLEA analysis of PCBs can provide reliable information to better monitor the sources and fate of these compounds in the environment.