Variation Of Polychlorinated Biphenyls Research Articles

Estimating the long term leaching potential of PCBs in soil

Polychlorinated Biphenyls (PCBs) are a group of man-made organic chemicals known as chlorinated hydrocarbons. PCBs were banned in 1979 due to its toxicity and persistence in the environment. Variations of PCBs were determined in soils and plants. Degradation of PCB Aroclors and congener patterns were investigated from known contaminated site at a former Military Air Base. PCB concentrations ranged between 17 - 1,040 µg L-1 at 0 - 0.5 m depth, between 36 - 898 µg L-1 at 1.0 - 1.5 m depth, between 20 - 73 µg L-1 at 4 m depth and 21 µg L-1 at 8 m depth. There is also a negative correlation between the mean of the Toxicity Characteristic Leaching Procedure (TCLP) of PCBs versus the sampling depth. Linear regression analyses were used to determine the correlation of the factors such as depth, Octanol/Water Partition Coefficient (Kow) and solubility affected Soil/Water Distribution Coefficient (Kd). Effects were found only when the soil depth is at 0.3 - 0.5 m (at 95% confidence level). Kd is positively correlated with Kow while Kd has some level of negative correlation with solubility. No effect was found at 1.0 - 1.5 m, 4.0 m, and 8.0 m. Organic Carbon/Water Partition Coefficient (Koc) showed high results exceeding the log Koc criteria of 4.5; as a result, this is now a matter of concern on the potential adverse effects of the substance on terrestrial organisms within its vicinity.

Comparison of trophic magnification factors of PCBs and PBDEs in Tokyo Bay based on nitrogen isotope ratios in bulk nitrogen and amino acids

Trophic positions (TPs) are key parameters for determining trophic magnification factors (TMFs) of environmental pollutants. We used compound-specific nitrogen isotope analysis of amino acids (CSIA-AA), with which we expected to obtain precise TPs, to estimate the TMFs of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the pelagic and benthic food webs of Tokyo Bay. The objective of the present study was to evaluate the difference between TMFs derived from TPs estimated by CSIA-AA (TPGlu/Phe) and TMFs derived from TPs estimated by bulk stable isotope analysis (TPbulk). TPGlu/Phe tended to be lower than TPbulk for many pelagic and benthic fishes. In the pelagic food web, the slopes for the relationships between PCB concentrations and TPGlu/Phe exceeded those between PCB concentrations and TPbulk for many congeners in samples from December 2014, and TMFGlu/Phe values (0.89–6.9) were higher than TMFbulk values (0.92–3.8). However, there were no statistically significant differences between the slopes of the relationships between PCB and PBDE concentrations and TPbulk or TPGlu/Phe for any of the congeners (analysis of covariance, P ≥ 0.08). In the benthic food web, PCB concentrations correlated with TPGlu/Phe for 9 PCB congeners in the samples collected during December 2014, although the concentrations of none of the PCB congeners correlated with TPbulk. A decrease of TMFGlu/Phe and TMFbulk values from December 2014 to May 2015 suggested that variation of PCB and PBDE concentrations in the organisms had more effect than TPs on the TMFs.