To compare the inorganic chemical compositions of TSP(total suspended paniculate),PM_(10)(particulate matter with an aerodynamic diameter less than 10 μm) and PM_(2.5)(particulate matter with an aerodynamic diameter less than 2.5 μm) in southern and northern cities in China,atmospheric particles were synchronously collected in Dalian(the northern city)and Xiamen(the southern city) in spring and autumn of 2004.The mass concentrations,twenty-three elements and nine soluble ions were assessed.The results show that in Dalian,the mass concentrations of Mg,Al,Ca,Mn and Fe in spring were 4.0-10.1,2.6-8.0,4.1-12,1.2-3.6 and 2.9-7.9 times higher,respectively,than those in Xiamen.The dust storm influence is more obvious in Dalian in spring.However,in Xiamen,heavy metals accounted for 13.9%-17.9%of TSP,while heavy metals contributed to 5.5%-9.3%of TSP in Dalian.These concentrations suggest that heavy metal pollution in Xiamen was more serious.In addition,the concentrations of Na~+,Cl~-,Ca~(2+) and Mg~(2+) were higher in Dalian due to the influence of marine aerosol,construction activities and soil dust.The NO~(3-)/SO_4~(2-) ratios in Dalian(0.25-0.49) were lower than those in Xiamen(0.51-0.62),indicating that the contributions of vehicle emission to particles in Xiamen were higher.Coefficient of divergence values was higher than 0.40,implying that the inorganic chemical composition profiles for the particles of Dalian and Xiamen were quite different from each other. 相似文献
Cyanobacterial blooms-produced microcystins are secondary metabolites which can accumulate in the food chain and contaminate water, thus posing a potential threat to the health of aquatic animals and even humans. Microcystin toxicity affects not only the liver but also the other organs, i.e., the brain. The serious neurotoxicity effects caused by microcystins then lead to various symptoms. This review focuses on the neurotoxicity of microcystins. Microcystins can cross blood-brain barrier with the transport of Oatps/OATPs, causing neurostructural, functional, and behavioral changes. In this review, potential uptake mechanisms and neurotoxicity mechanisms are summarized, including neurotransmissions, neurochannels, signal transduction, oxidative stress, and cytoskeleton disruption. However, further researches are needed for detailed studies on signaling pathways and the downstream pathways of neurotoxicity of microcystins. 相似文献
The public health and ecological impacts of volatile organic compound (VOCs) pollution have become a serious problem in China, arousing increasing attention to emissions control. In this context, this paper analyses the effectiveness of VOC reduction policies, namely pollution charges and environmental taxes at the national and industrial sector levels. It uses a computable general equilibrium model, which connects macroeconomic variables with VOC emissions inventory, to simulate the effects of policy scenarios (with 2007 as the reference year). This paper shows that VOC emissions are reduced by 2.2% when a pollution charge equal to the average cost of engineering reduction methods – the traditional approach to regulation in China – is applied. In order to achieve a similar reduction, an 8.9% indirect tax would have to be imposed. It concludes that an environmental tax should be the preferred method of VOC regulation due to its smaller footprint on the macroeconomy. Other policies, such as subsidies, should be used as supplements. 相似文献
Journal of Material Cycles and Waste Management - Disposal of waste CRT glass is now an urgent environmental protection issue. We collected waste CRT glass from monochrome and color television... 相似文献