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861.
太湖北部表层沉积物重金属污染及其生物毒性研究 总被引:2,自引:0,他引:2
在分析太湖北部梅梁湾、竺山湾和贡湖表层沉积物和野生铜锈环棱螺体内重金属残留水平基础上,利用潜在生态危害指数法评价了区域重金属污染的潜在生态风险,并利用综合污染指数法评价了野生铜锈环棱螺受重金属污染的状况。研究结果表明,3个区域表层沉积物孔隙水的生物综合毒性处于低毒到中毒水平,而表层沉积物重金属污染均处于较低的生态风险,但3个区域的野生铜锈环棱螺体内重金属的综合污染指数处于中度到重度的污染水平。由此可以得出太湖北部沉积物重金属污染对底栖生物仍具有一定的潜在生态风险。 相似文献
862.
Wei Chao Guo Huaming Zhang Di Wu Yang Han Shuangbao An Yonghui Zhang Fucun 《Environmental geochemistry and health》2016,38(1):275-290
Environmental Geochemistry and Health - High-F− groundwater is widely distributed in Xiji County, which endangers the safety of drinking water. In order to evaluate the key factors... 相似文献
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867.
土壤中苯氧羧酸类除草剂的降解动态 总被引:5,自引:0,他引:5
在室内模拟条件下研究了 2甲 4氯、2,4-D和除草醚在土壤中的降解动态 .将它们放在 3种不同有机质含量的土壤中培养 ,隔一段时间取出测定它们在土壤中的含量 ,发现随着时间的延长 ,它们的含量在逐渐减少 .在未考虑土壤中微生物的作用时 ,上述 3种农药在土壤中的稳定性与土壤中的有机质含量及 pH值似乎存在一定的相关性 .除草剂在有机质含量高的土壤中降解较快 ,2甲 4氯 ,2 ,4-D和除草醚在黑土中的降解半衰期分别为 28.6d,27.3d,71.5d;而在红土中的降解半衰期分别为223.6d,301.4d,97.6d,苯氧羧酸类除草剂在酸性土壤中表现得更为稳定 . 相似文献
868.
Sensitivity of air quality model prediction to parameterization of vertical eddy diffusivity 总被引:1,自引:0,他引:1
This paper investigates the effects of vertical eddy diffusivities derived from the 3 different planetary boundary layer (PBL)
schemes on predictions of chemical components in the troposphere of East Asia. Three PBL schemes were incorporated into a
regional air quality model (RAQM) to represent vertical mixing process and sensitivity simulations were conducted with the
three schemes while other options are identical. At altitudes <2km, all schemes exhibit similar skill for predicting SO2 and O3, but more difference in the predicted NOx concentration. The Gayno–Seaman scheme produces the smallest vertical eddy diffusivity (Kz) among all schemes, leading to
higher SO2 and NOx concentrations near the surface than that from the other 2 schemes. However, the effect of vertical mixing on O3 concentration is complex and varies spatially due to chemistry. The Gayno–Seaman scheme predicts lower O3 concentrations than the other two schemes in the parts of northern China (generally VOC-limited) and higher ones in most
parts of southern China (NOx-limited). The Byun and Dennis scheme produces the largest mixing depth in the daytime, which bring more NOx into upper levels, and the mixing depth predicted by the Gayno–Seaman scheme is the smallest, leading to higher NOx and lower O3 concentrations near the surface over intensive emission regions. 相似文献
869.
An YJ 《Chemosphere》2006,62(8):1359-1365
The acute toxicities of lead (Pb) and copper (Cu) to important crop plants Sorghum bicolor, Cucumis sativus, Triticum aestivum, and Zea mays were compared. The EC50 values (the concentration of metals in the soil that reduces the growth of shoots and roots by 50%) were derived using the Trimmed Spearman-Karber method. The EC50s-shoot (root) in mg Pb kg-1 dry soil and mg Cu kg-1 dry soil were in the range of 519 to >1280 (285-445), and 48-232 (<40-110), respectively. Those concentrations are likely to occur in some abandoned mine areas in Korea. The figures indicate that Cu is more toxic than Pb to the plants in this study, and that root growth is more sensitive to the toxicity endpoint than shoot growth in Cu- or Pb-amended soils. On the other hand, seed germination is insensitive to both Pb and Cu toxicities. The Pb- and Cu-sensitive plants were also identified. Among the plants tested, T. aestivum and S. bicolor were most sensitive to Pb and Cu, respectively. Z. mays was most resistant to both Pb and Cu. The combined effects of Pb and Cu depend on the plant species, and no general phenomenon was observed. Bioaccumulations of Pb and Cu were observed in all test species, and they are concentration-dependent. These differences in the toxicities of Pb and Cu in plant species should be taken into account in biomonitoring and ecological risk assessment. 相似文献
870.
栉孔扇贝内参基因稳定性研究 总被引:3,自引:2,他引:1
合适的内参基因对准确定量目标基因表达水平非常重要。利用实时定量聚合酶链式反应(RT-qPCR)分析了不同发育阶段和雌激素暴露条件下栉孔扇贝性腺组织中β-actin、β-TUB、EF-lα、18SrRNA和GAPDH5个内参基因的表达水平,并利用RefFinder软件对其表达稳定性进行了分析。结果表明:在所考察的内参基因中,EF-lα在栉孔扇贝不同发育阶段和雌激素暴露下的表达均最为稳定,可作为定量目标基因表达水平的内参基因之一。 相似文献