[Distribution Characteristics and Pollution Evaluation of Heavy Metals in Greenbelt Soils of Nanjing City].

Concentrations and the spatial distribution of heavy metals (Cr, Cu, Zn, Pb, and Cd) in greenbelt soils in the main areas of Nanjing City, Jiangsu Province, were investigated and pollution levels were assessed using the single factor pollution index (SFPI), Nemerow integrated pollution index (NIPI), and potential ecological risk coefficient (PERC). The results showed that the average concentrations of heavy metals in greenbelt soils exceeded their background values, with the SFPI results ranked Cd > Pb > Cr > Cu > Zn, and the mean NIPI was 2.72 indicating that the greenbelt soils are moderately polluted. The PERC of each heavy metal (Cr, Cu, Zn, and Pb) was less than 10, indicating that the greenbelt soils present a slight ecological risk, while the PERC of Cd reached 97.32, indicating a strong ecological risk. The composite PERC of all heavy metals was less than 150, indicating a slight ecological risk overall. The five heavy metals showed a patchy spatial distribution, with high concentrations of Cr, Cu, Zn, and Pb in the greenbelt soils of northeast areas, and high concentrations of Cd in the southwest and northwest. Based on the results of study, Cd pollution in greenbelt soils in main areas of Nanjing City is relatively serious, which requires further attention.

[Analysis on heavy metal concentrations in agricultural soils of Baoshan, Shanghai].

Based on the acquisition of heavy metal data from 216 topsoil samples of the agricultural land in Baoshan District, a typical region of Shanghai City, the content, distribution characteristics and sources of the heavy metals in agricultural soil of Shanghai Baoshan District were analyzed with the methods of combining multivariate statistics and geo-statistical. The results show that the average concentrations of the Cd, Hg, As, Cr, Pb, Cu and Zn in agricultural soil of Baoshan District are 0.195, 0.148, 7.44, 82.5, 29.1, 33.2 and 124.5 mg x kg(-1), they are lower than the secondary standards of the national soil environment; but the average concentrations of the Cd, Hg, Cr, Pb, Cu and Zn are more than background values of soil in Shanghai. Especially the Cd, Hg, Zn, they are 1.50, 1.48, 1.45 times higher than the background values, showing a net cumulative trend. The results of correlation analysis and factor analysis show that the sources of these elements can be divided into three categories; the Zn, Cd, Hg and Pb as one class; the Cr and Cu as another class; the As in a separate category. The concentrations of the former two classes are much higher than the background value, implying mainly from various human activities; the content of the As is almost the same as the background value of soil, it has the lowest degree of variation. Spatial structure analysis shows that the distribution of the As is influenced by the soil structural variations, such as soil parent material, topography, and other elements are mainly affected by random factors of human activities. Through the probability distribution of contour lines of the critical value, it can be found that the Cd, Zn, Cr, Cu, Hg come mainly from the point sources of pollution, but the source of Pb is relatively dispersed.

EST analysis of mRNAs expressed in neurula of Chinese amphioxus.

Amphioxus, a cephalochordate, is the closest living relative to the vertebrates. In order to investigate the molecular mechanisms of the early embryogenesis of amphioxus, we constructed a neurula embryo cDNA library of Chinese amphioxus (Branchiostoma belcheri tsingtauense) and generated 5235 expressed sequenced tags in the present study. The initial ESTs consisted of 638 clusters and 1855 singletons, which revealed approximately 2493 unique genes in the data set. Of these sequences, 35.52% ESTs matched to known genes, 12.76% matched to other ESTs, and 51.71% had no match to any known sequences in GenBank. Interestingly we found homologous genes related to neural development and human disease. Bioinformatic analysis showed the direct evidence that the gene homologue found only in vertebrates in previous studies also exists in the amphioxus genome. This study provides a preliminary view of the gene information involved in the development of neurula embryos of Chinese amphioxus and helps our understanding of vertebrate evolution at gene level.