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201.
Distribution of organochlorine compounds in the sea-surface microlayer, water column and sediment of Singapore's coastal environment 总被引:1,自引:0,他引:1
Hexachlorocyclohexanes (HCHs), dichlorodiphenylethanes (DDTs) and 38 PCB congeners were determined in the water column (sea-surface microlayer, subsurface, mid-depth and bottom water) and sediments from Singapore's coastal environment. The concentration ranges for summationHCHs, summationDDTs and summationPCBs in the seawater dissolved phase (DP) were 101-6110 (mean 1833), <5-405 (mean 76) and 60-6979 (mean 1611)pg/l, respectively. The concentration ranges for summationHCHs, summationDDTs and summationPCBs in the suspended particulate matter (SPM) were 26-2395 (mean 243), <5-124 (mean 19) and 38-3793 (mean 715) pg/l, respectively. Concentration levels in sediments ranged between 521 and 1758 (mean 1094), 50 and 290 (mean 88) and 339 and 1356 (mean 858) pg/g for summationHCHs, summationDDTs and summationPCBs, respectively. It was shown that the interfaces of the sea-surface microlayer (SML) and near bottom water are important compartments for the distribution of organochlorine compounds (OCs) in the water column. In comparison with data from China, the concentration levels in the water column and sediments of Singapore can be considered as low, but the reported levels were higher compared to available data from Europe. 相似文献
202.
We measured total mercury concentrations in water and fish of Lake Managua and Lake Apoyo. Water mercury concentrations were 10-fold higher in Lake Managua than in Lake Apoyo, although differences in mercury concentration in the most common native fish were not significant. One-fourth of the commercially fished tilapia in Lake Managua exceeded maximum recommended mercury levels for consumption among pregnant women and other at-risk groups, although bioavailability to fishes was lower than in previously studied sites in Brazil and Western Maryland. The lower bioavailiability may present important information for management options to reduce mercury exposure to fishes and humans. We recommend closer mercury monitoring among freshwater fish destined for international commerce. 相似文献
203.
Viswanathan S Eria L Diunugala N Johnson J McClean C 《Journal of the Air & Waste Management Association (1995)》2006,56(1):56-67
The impact of major gaseous and particulate pollutants emitted by the wildfire of October 2003 on ambient air quality and health of San Diego residents before, during, and after the fire are analyzed using data available from the San Diego County Air Pollution Control District and California Air Resources Board. It was found that fine particulate matter (PM) levels exceeded the federal daily 24-hr average standard during the fire. There was a slight increase in some of the gaseous pollutants, such as carbon monoxide, which exceeded federal standards. Ozone (O3) precursors, such as total hydrocarbons and methane gases, experienced elevated concentration during the fire. Fortunately, the absence of sunlight because of the cloud of thick smoke that covered most of the county during the fire appears to have prevented the photochemical conversion of the precursor gases to harmful concentrations of O3. Statistical analysis of the compiled medical surveillance data has been used to establish correlations between pollutant levels in the region and the resultant health problems experienced by the county citizens. The study shows that the increased PM concentration above the federal standard resulted in a significant increase in hospital emergency room visits for asthma, respiratory problems, eye irritation, and smoke inhalation. On the basis of the findings, it is recommended that hospitals and emergency medical facilities engage in pre-event planning that would ensure a rapid response to an impact on the healthcare system as a result of a large wildfire and appropriate agencies engage in the use of all available meteorological forecasting resources, including real-time satellite imaging assets, to accurately forecast air quality and assist firefighting efforts. 相似文献
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207.
Eric D. Larson Ernst Worrell Jeffrey S. Chen 《Resources, Conservation and Recycling》1996,17(4):273-298
Increasing volumes of municipal solid waste (MSW) pose disposal problems for many cities. Costs are rising as landfilling becomes more difficult. The production of clean transportation fuels (methanol or hydrogen) from MSW is one economically and environmentally promising option for dealing with these problems. An attractive feature is that elimination of essentially all air pollutant emissions is inherent in the process. Current and future air emissions standards should be easily met. Methanol or hydrogen used in fuel cell vehicles (FCV) can help address problems of deteriorating urban air quality due to vehicle pollution and heavy dependence of the transport sector on imported petroleum. Buses are initial targets for commercial application of fuel cells. Coupled with FCVs, MSW could become a major transportation energy resource. For example, less than 25% of New York City's MSW supply would be sufficient to produce the methanol or hydrogen needed to fuel the entire city's bus fleet, if the buses were fuel cell powered. Estimated breakeven tipping fees required for hydrogen or methanol from MSW to compete with the cost of these fuels made from natural gas today are $52 to $89/raw tonne MSW for hydrogen and $64 to $104/raw tonne MSW for methanol (in 1991$), depending on the gasification technology considered. For comparison, the average tipping fee today in New York City is $74/tonne (1991$). Because of the high fuel economies expected for fuel cell buses, total lifecycle costs per bus-km could be lower than for conventional diesel-engine buses. 相似文献
208.
Angel Hsu Amy Weinfurter Jeffrey Tong Yihao Xie 《Journal of Environmental Policy & Planning》2020,22(1):138-153
ABSTRACTInformation communication technologies (ICTs) generate new forums for transparency via governance-by-disclosure initiatives designed to improve environmental management and policy. Data generated by these programs are a means to empower citizens, narrowing the accountability gap between governments and people and enhancing public service. There is little empirical evidence, however, that supports the theory that citizen-generated data can be used to improve the accountability of local government officials. Citizen-led transparency efforts are emerging in China, as the country undergoes an information revolution that has brought ICTs to near ubiquity. We evaluate the transformative potential of a new ICT initiative, the ‘Black and Smelly Waters’ program, which China’s government launched to help enforce local government water remediation efforts. Many examples of citizen-generated transparency are grassroots initiatives, yet the Black and Smelly Waters program is distinct in its top-down structure. An empirical evaluation of preliminary data illuminates Black and Smelly Waters’s early successes and challenges as a means to generate transparency and accountability. We discuss these findings and propose a broad application of this new type of disclosure to reshape environmental management in China. 相似文献
209.
The responses of ecological computer simulations are significantly changed by the inclusion of human behavior patterns. Two computer simulations illustrate this principle for internal and external decision making. The Northwest Educational Trawler Simulation (NETS) models the interaction between fish populations, fishing effort, markets, and a fishing community. This simulation includes an internal decision making submodel for changing fishing effort based on observed behaviors of fishermen. NOGERO, a simulation of a mythical coastal fishing culture, uses external decision making where simulation users act as stewards. The patterns of model response vary depending on the attitudes and goals of decision makers. This shows how human behavior interacts with ecosystem dynamics to produce a variety of results. 相似文献
210.
Mammalian communities were studied on 10 surface mines over a four year period. The size and composition of these communities varied among the different areas. The size, composition, and spatial distribution of these mammalian communities were related to the structure of the plant community, and native plant species were of greater importance in determining size and composition of these communities than were those used in reclamation. 相似文献