The single and combinational effects of cadmium （Cd） and fluoranthene （FLT） on germination, growth and photosynthesis of soybean seedlings were investigated. Exposure to 5, 10, or 15 mg Cd/L or 1, 5, or 10 mg FLT/L individually or in combination significantly decreased germination vigor （3 days） and final germination rate of soybean seeds, except at 1 and 5 mg FLT/L. The results of two-way ANOVA analysis and the Bliss independence model showed that at lower concentrations of FLT （1 mg/L）, the interaction between Cd and FLT on germination was antagonistic, whereas the interaction was synergistic when the concentration of FLT was 5 or 10 mg/L and the concentration of Cd was 15 mg/L. Growth, expressed as dry weight, length of shoot and root, leaf area, and photosynthesis, expressed as net photosynthetic rate, intercellular CO2 concentration, chlorophyll contents and fluorescence of soybean seedlings were also reduced by exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L, singly or jointly. Significant antagonistic effects of exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L on shoot growth and photosynthesis were observed, whereas synergy and antagonism of Cd and FLT were both observed for root growth.
Topsoil samples from 61 sites around the Guanting Reservoir,China,were measured for Cu,Zn,Cr,Ni,Cd,Pb and As concentrations.The mean concentrations of Cu,Zn,Cr,Ni,Cd,Pb and As were 16.8,59.4,37.8,18.3,0.32,20.1 and 8.67 mg/kg dry weight,respectively.Factors that influence the dynamics of these metals in soils around the watersheds of Beijing reservoirs were examined.The influence of atmospheric deposition,land use,soil texture,soil type and soil chemical parameters on metal contents in soils was investigated.Atmospheric deposition,land use and soil texture were the important factors affecting heavy metal residues.Soil type and soil chemical parameters were also involved in heavy metal retention in soils.The data provided in this study are considered crucial for reservoir remediation,especially since the Guanting Reservoir will serve as one of the main drinking water sources for Beijing in the foreseeable future.
Li XuTieyu WangWei LuoKun NiShijie LiuLin WangQiushuang LiYonglong Lu
Analyzing determinants that influence polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran（PCDD/F） emissions is helpful for decision-makers to find effective and efficient ways to mitigate PCDD/F emissions. The PCDD/F emissions and the contributions of the scale effect, structure effect and technology effect to emissions from eight main industrial sectors in2006, 2008 and 2010 in Shandong Province, were calculated in this article. Total PCDD/F emissions in Shandong increased by 52.8% in 2008（614.1 g I-TEQ） and 49.7% in 2010（601.8 g I-TEQ） based on 2006（401.9 g I-TEQ）. According to the decomposition method, the largest influencing factor on PCDD/F emission changes was the composition effect（contributed 43.4%in 2008 and 120.6% in 2010 based on 2006）, which was also an emission-increasing factor.In this case, the present industrial restructuring policy should be adjusted to control the proportion of production capacities with high emission factors, such as iron ore sintering and steelmaking and the secondary non-ferrous metal sector. The scale effect increased the emissions in 2008（contributed 21.9%） and decreased the emissions in 2010（contributed-28.0%）. However, as a source control measure, the excess capacity control policy indeed had a significant role in emission reduction. The main reason for the technology effect（contributed 34.7% in 2008 and 7.4% in 2010 based on 2006） having an emission-increasing role was the weakness in implementing policies for restricting industries with outdated facilities. Some specific suggestions were proposed on PCDD/F reduction for local administrators at the end.
Lin WangYonglong LuGuizhen HeArthur P.J.MolTieyu WangJorrit GosensKun Ni
