Distribution of polychlorinated biphenyls in soil around three typical industrial sites in Beijing, China.

We investigated three locations in Beijing, China, containing different industrial plants that may cause pollution of polychlorinated biphenyls (PCBs). The highest soil concentration of 1,000 pg g(-1) (dry wt) was found in the chemical plant. The concentrations of ΣPCBs tended to decrease with distance from each of the investigated sites. The principal component analysis demonstrated that there were not substantial differences in PCB homologue patterns among these industrial sites. Tri-CBs and tetra-CBs were the dominant congeners. Based on the data obtained in this investigation, further study of the emission of PCBs from these industrial sites in Beijing is warranted.

[Analysis of ecological risk and the content situation of polybrominated diphenyl ethers in sediments from Northeast China River Basin].

To investigate the polybrominated diphenyl ethers (PBDEs) pollution status, sediment samples were collected from major rivers in northeast China. Contents of 41 PBDEs congeners in sediments were measured using GC-NCI-MS. BDE209 was not detected, measured level of total PBDEs (excluding BDE209) ranged from 0.91 to 17.67 ng.g-1 dry weight, the highest concentrations of PBDEs were detected in the sediment samples from upstream and downstream of Jilin City in the Second Songhua River Basin, with 15.86 and 17.67 ng.g-1. BDE207 and BDE47 were the predominant PBDE congeners, with their concentrations accounting for 86. 5% and 76. 6% of the total PBDEs concentration measured in the samples. Each congener content difference was not obvious in other river sediments. PBDEs levels monitored in the present study were compared to those reported recently for districts located at home and abroad, and with ecological risk analysis. PBDEs content is at a low level in sediments of Northeast China River Basin and there is no ecological risk.

[Distribution characteristics and environmental significance of heavy metals in soil particle size fractions from tropical forests in China].

Three tropical forest soils were collected from Haikou, Qionghai and Tunchang in Hainan Island. Soil particle size fractionations were conducted using the standard dry-sieving procedure. Distribution of heavy metals in bulk samples and particle size fractions was determined by ICP-MS. The distribution characteristics and the response to organic carbon and iron were discussed. The results showed that the distribution of heavy metals was highly associated with the particle size fractions and variable patterns were found, which decreased with the increasing size. The accumulation of Cr, Ni, Cu, Zn, Cd and Cd was predominantly contributed by the particles finer than < 53 microm in diameter, whereas As mainly accumulated in particle size of 53-1 000 microm. Generally, the microaggregate (< 250 microm) contributed 14.38%-65.04% of heavy metals to the contents in bulk soil and the silt-clay aggregates (< 53 microm) contributed 2.61% -32.01%. The content of heavy metals except for As and Cd and Pb in Haikou soil in these different size fractions were controlled by the organic carbon and iron contents, which increased with the decreasing particle size.

[Distribution, sources and ecological risk assessment of polychlorinated biphenyl in sediments from Songhua River Basin].

In order to find out the distribution, source and pollution situation of Polychlorinated Biphenyls (PCBs) in sediments of Songhua River basin, GC-ECD and GC-MS were used to determine the PCBs contents in sediments of Songhua River basin. Regulations of the United States Environmental Protection Agency (EPA), the Canadian Sediment Quality Guidelines (SQG) and the potential ecological risk index (Er) were utilized to evaluate the ecological risk of PCBs in the sediments. The results showed that 2-10 PCBs congeners were detected in the sediments. The total contents of PCBs varied from 0.83 ng x g(-1) to 125.53 ng x g(-1) in sediments of Songhua river basin, 0.83-4.44 ng x g(-1) for Nen River, 12.44-125.53 ng x g(-1) for Second Songhua River, and 1.74-6.25 ng x g(-1) for the mainstream of Songhua River. The highest level of PCBs was detected in sediments of Second Songhua River, which mainly came from pollution sources which are related with industrial products such as paint, insulation materials and the like, and were distributed along the river. While in other rivers, the dominant PCB was Dichlorobiphenyl, which mainly came from the atmospheric deposition. Risk assessment using three methods (EPA, SQG and Er) showed that PCBs in the sediment of the Second Songhua River has already reached the medium to high level of contamination, and PCBs in sediments of other rivers has no ecological risks at the moment.