The factors controlling the partitioning of polybrominated diphenyl ethers and polychlorinated biphenyls in the water-column of the Pearl River Estuary in South China.

In this study, the distribution and partition of polybrominateddiphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in water from the Pearl River Estuary were investigated. A seasonal dependence for dissolved and particle phase PCB and PBDE levels was observed. A high dissolved phase level occurred in the dry season. The positive correlation between POC content in the particles and phase distribution coefficients (K(p)) suggested that POC may play an important role in determining the partition of PBDEs and PCBs. A linear correlation between the observed log K(OC) and log K(OW) for PBDEs and PCBs was found with slopes less than one. The observed log K(OC) values were lower than the predicted log K(OC) values for PBDEs (except for BDE28). The log K(OC) values were higher than the predicted values for PCBs. A combination of sorption to colloids (10-98% for PBDEs and less than 25% for PCBs) and adsorption to BC was responsible for this observation.