Residual effect of Polychlorinated biphenyls (PCBs) in sediment from CauBay River, Vietnam

Abstract

Background An evaluation of residual effect of Polychlorinated biphenyls (PCBs) in sediment from CauBay River, Vietnam was carried out. This river has been playing an important role in water supply and drainage for agriculture at Kieu Ky commune, Hanoi, the capital of Vietnam. Aims The aims of the this research are to assess the PCBs residue in sediment and its effect to the quality of soil of Kieu Ky commune at the downstream of CauBay river. Methods Twenty representative sediment and soil samples were collected in October 2012. The concentrations of PCBs in the sediment samples were investigated by GC/MS. Results In industrial and urban sampling sites, PCBs concentrations in sediment samples ranged from 10.02 to 169.52 ng g-1 dry weight, while those in agricultural sampling sites ranged from 8.02 to 24.37 ng g-1 dry weight. All sediment samples in CauBay river are lower than ERM level (180 ng g-1) and ninety percent of samples are higher than ERL level (22.7 ng g-1). Compositions analyses show that the predominance of heavily chlorinated PCBs, PCB138 and PCB153, are still remained when they penetrated the sediment from CauBay river and soil from Kieu Ky commune. In soil sample from Kieu Ky commune, PCBs was detected from 9.08 to 110.62 ng g-1 dry weight. There is a strong positive relation between residue of PCBs from sediment of CauBay river and from soil of Kieu Ky commune (Pearson’ correlation coefficient is 0.87). Conclusions Wide occurrence and high residue of PCBs has been found in the study area. There is a strong positive relation between residue of PCBs from sediment of CauBay river and from soil of Kieu Ky commune. Compositions analyses show that the predominance of heavily chlorinated PCBs are still remained when they penetrated CauBay river. The long-time release of PCBs levels is observed.