To assess impacts and risks of sediments dredging on water environmental quality of Wulihu Lake, the principal components analysis method and the Monte Carlo romantic sampling model were used. Five principal constitue...
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To assess impacts and risks of sediments dredging on water environmental quality of Wulihu Lake, the principal components analysis method and the Monte Carlo romantic sampling model were used. Five principal constituents of Wulihu Lake were generalized and defined by using sixteen water quality index data, and it was studied the characteristics of the variation of every principal component and the comprehensive component with sediment dredging. The result show that during sediment dredging the water quality of Wulihu Lake were more serious, and the values of the comprehensive component and the principal component Fl increased to the highest level, were 1.15 and 5.0, respectively. This indicated that sediment dredging had great impacts on the water environment of Wulihu Lake, including sediment re-suspension, water transparency decrease, release of the internal nutrients and heavy metal ions etc. The risk of heavy metal release from re-suspended sediments and its certainty level were assessed and forecasted with the equilibrium partitioning model and the Monte Carlo romantic sampling method. The results also suggested that during sediment dredging, most of heavy metal ions have a great risk of release from re-suspended sediments with the certainty level over 90%;especially for Ni2+ and As, the release levels of which were 28.6% ~ + infinity of EQS and 34% ~ + infinity of EQS, respectively. Thus, sediment dredging would cause a temporary risk of water quality deterioration in Wulihu Lake. Others, the application of Monte Carlo sampling model may offer a new tool to assess a potential risk of deteriorations in water environment with sediments dredging.
作者：
WANG Xiaodong XIAO Qianfen CUI Shihai LIU Shushen YIN Daqiang WANG LianshengState Key Laboratory of Pollution Control and Resources Reuse
School of the Environment Nanjing University Nanjing 210093 China State Key Laboratory of Pollution Control and Resources ReuseSchool of the Environment Nanjing University Nanjing 210093 China State Key Laboratory of Pollution Control and Resources ReuseSchool of the Environment Nanjing University Nanjing 210093 China State Key Laboratory of Pollution Control and Resources ReuseSchool of the Environment Nanjing University Nanjing 210093 China State Key Laboratory of Pollution Control and Resources ReuseSchool of the Environment Nanjing University Nanjing 210093 China State Key Laboratory of Pollution Control and Resources ReuseSchool of the Environment Nanjing University Nanjing 210093 China
Experimental and epidemiological studies suggest that some man-made and natu- rally occurring chemicals related to the environment have the potential to interrupt normal func- tioning of the endocrine systems of human...
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Experimental and epidemiological studies suggest that some man-made and natu- rally occurring chemicals related to the environment have the potential to interrupt normal func- tioning of the endocrine systems of humans and wildlife. These chemicals, termed EDCs (Endo- crine disrupting Chemicals), pose serious threats to the reproductive capability of humans and wildlife. Because of the structural diversity and various types, development of structure-based rapid screening methodologies is important and necessary for the assessment of the environ- mental pollutants. In this paper molecular hologram based QSAR models were developed with the combinatory application of partial least square (PLS) regression for a large diverse set of 105 environmental estrogens. Quantitatively predictive models were developed based on only mo- lecular structures, which can be used for the accurate prediction of estrogenicity to rapidly screen potential environmental endocrine disrupting chemicals.
作者：
HU Min ZHANG Jing WU ZhijunState Key Joint Laboratory of Environmental Simulation and Pollution Control
College of Environmental Sciences Peking University Beijing 100871 China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China
Totally 23 precipitation samples were collected in Beijing from May to November in 2003. In order to investigate the chemical composition of precipitation samples, pH, conductivity, concentrations of water-soluble ion...
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Totally 23 precipitation samples were collected in Beijing from May to November in 2003. In order to investigate the chemical composition of precipitation samples, pH, conductivity, concentrations of water-soluble ions and organic acids were analyzed. The average pH of pre-cipitations is 6.18, belonging to the neutral range; the average conductivity is 52.23 μS/cm, which indicates that precipitations in Beijing are obviously polluted; SO 24? , NO3 ? are the most abundant anions with the average concentrations of 521 and 174 μeq·L?1, respectively; the average 2SO 4? /NO3? equivalent ratio is 3.1, which decreases by about 15% compared with the result of 1994; NH+ 4 and Ca2+ are the most abundant cations with the average concentrations of 376 and 397 μeq·L?1, respectively; formic acid, acetic acid and oxalic acid are the main organic acids with the average concentrations of 4.62, 4.60 and 1.17 μeq·L?1, respectively, accounting for 2% of the overall anions. Obvious differences between concentrations before and after precipitation are also observed by SJAC (Steam Jet Aerosol Collector), which shows the removal of particles from the atmosphere by precipitation.
Volatile organic compounds(VOCs)are important precursors of atmospheric chemical *** a whole mixture,the ambient VOCs show very strong chemical *** on OH radical loss rates in the air,the chemical reactivity of VOCs i...
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Volatile organic compounds(VOCs)are important precursors of atmospheric chemical *** a whole mixture,the ambient VOCs show very strong chemical *** on OH radical loss rates in the air,the chemical reactivity of VOCs in Beijing was *** results revealed that alkenes,accounting for only about 15%in the mixing ratio of VOCs,provide nearly 75%of the reactivity of ambient VOCs and the C4 to C5 alkenes were the major reactive species among the *** study of emission characteristics of various VOCs sources indicated that these alkenes are mainly from vehicle exhaust and gasoline *** reduction of alkene species in these two sources will be effective in photochemical pollutioncontrol in Beijing.
Supplying water to the ecological environment with certain quantity and quality is significant for the protection of diversity and the realization of sustainable development. The conception and connotation of eco-envi...
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Supplying water to the ecological environment with certain quantity and quality is significant for the protection of diversity and the realization of sustainable development. The conception and connotation of eco-environmental water requirements, including the definition of the conception, the composition and characteristics of eco-environmental water requirements, are evaluated in this paper. The classification and estimation methods of eco-environmental water requirements are then proposed. On the basis of the study on the Huang-Huai-Hai Area, the present water use, the minimum and suitable water requirement are estimated and the cor-responding water shortage is also calculated. According to the interrelated programs, the eco-environmental water requirements in the coming years (2010, 2030, 2050) are estimated. The result indicates that the minimum and suitable eco-environmental water requirements fluc-tuate with the differences of function setting and the referential standard of water resources, and so as the water shortage. Moreover, the study indicates that the minimum eco-environmental water requirement of the study area ranges from 2.84×1010m3 to 1.02×1011m3, the suitable water requirement ranges from 6.45×1010m3 to 1.78×1011m3, the water shortage ranges from 9.1×109m3 to 2.16×1010m3 under the minimum water requirement, and it is from 3.07×1010m3 to 7.53×1010m3 under the suitable water requirement. According to the different values of the water shortage, the water priority can be allocated. The ranges of the eco-environmental water re-quirements in the three coming years (2010, 2030, 2050) are 4.49×1010m3?1.73×1011m3, 5.99×10m3?2.09×1011m3, and 7.44×1010m3?2.52×1011m3, respectively.
The seasonal variations of dissolved nitrogen and phosphorus in the surface sediments from 3 lake regions of gulfs of Meiliang, Gonghu and Xukou of different trophic levels in the northeast part of Lake Taihu were stu...
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The seasonal variations of dissolved nitrogen and phosphorus in the surface sediments from 3 lake regions of gulfs of Meiliang, Gonghu and Xukou of different trophic levels in the northeast part of Lake Taihu were studied through rapid release experiment. There was significant correlation between total phosphorus (TP) and its released dissolved total phosphorus (DTP) in spring and summer, and dissolved organic phosphorus (DOP) was the main one. The form transformation of DOP and dissolved inorganic phosphorus (DIP) was more active in spring and summer than autumn and winter. The total nitrogen (TN) of the sediments of alga type lake region decreased in summer, and the total nitrogen increased greatly in sediments of clean type lake region in summer. The NH4+-N released from sediments was higher in summer and winter, and reached the greatest value in summer;the NO3--N released from sediments in summer increased greatly and little relatively in winter. The TN of sediments in summer and its released NH4--N, NO3--N in the clean type region were higher markedly than these in the alga type region.
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