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An existing model of radiocaesium transfer to grasses was extended to include wheat and barley and parameterised using data from a wide range of soils and contact times. The model structure was revised and evaluated using a subset of the available data which was not used for model parameterisation. The resulting model was then used as a basis for systematic model reduction to test the utility of the model components. This analysis suggested that the use of 4 model variables (relating to radiocaesium adsorption on organic matter and the pH sensitivity of soil solution potassium concentration) and 1 model input (pH) are not required. The results of this analysis were used to develop a reduced model which was further evaluated in terms of comparisons to observations. The reduced model had an improved empirical performance and fewer adjustable parameters and soil characteristic inputs. 相似文献
44.
Natural and anthropogenic influences on heavy metals in airborne particles over the Korean Peninsula
Young Sung Ghim Yongjoo Choi Young-Soo Chang Jeongsoo Kim 《Environmental science and pollution research international》2014,21(18):10713-10724
Six monitoring stations were selected to characterize the variations in airborne concentrations of heavy metals in South Korea between 1999 and 2012. Three stations represented higher concentrations, and three represented lower concentrations. The heavy metals monitored at these stations include cadmium, chromium, copper, iron (Fe), lead, manganese (Mn), and nickel. During the study period, concentrations of heavy metals at many stations, including those around the Seoul metropolitan area, showed a decreasing trend. However, concentrations of Mn and Fe that are primarily of crustal origin increased at four of the six stations. Some stations were significantly affected by emissions from the local industrial complex (IC), and heavy metal concentrations at those stations were relatively high even in summer. Many heavy metal concentrations were higher in spring than in winter, but wintertime concentrations of Cr and Pb were higher at the stations representing lower concentrations due to the dominant influence of combustion emissions. At stations less affected by emissions from the IC, concentrations of Fe and Mn that are predominantly crustal in origin were higher in spring, when Asian dust (AD) events are most frequent. Although Mn concentrations were also high at stations within the steelmaking IC during AD periods, they were much higher during non-AD periods due to local emissions. Variations in heavy metal concentrations, which are heavily influenced by emissions from the IC, warrant individual analysis because their emission characteristics differ from those of typical cases. 相似文献
45.
Hye-Jin Kim Kyung-Suk Cho Mark N. Goltz Jee-Hyeong Khim Jae Young Kim 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1237-1244
ABSTRACT To test the possible use of composted food waste and wastewater sludge as biofilters to treat gas-phase volatile organic compounds (VOCs), batch experiments were conducted with an isolated strain that could degrade aromatic compounds under aerobic conditions. A benzene and trichloroethylene (TCE) mixture was used as the gas-phase pollutant in experiments with composted food waste, sludge, and soil. Under aerobic conditions, benzene was degraded as a primary substrate and TCE was degraded cometabolically, with water contents varying from 6 to 60% (volume of water added/volume of solid). Optimal water content for VOC removal was 12% for the soil, 36% for the composted food waste, and 48% for the sludge. The extent of VOC sorption and biodegradation at the optimal water content was different for each material. With the same initial VOC concentration, more VOCs were removed by sorption onto the composted food waste and the sludge, while less VOCs were biodegraded in comparison with the results using soil. The reason the biodegradation in the soil was greater may be partly attributed to the fact that, due to less sorption, the aqueous-phase concentration of VOCs, which microorganisms could utilize as a carbon source or cometabolize, was higher. We also speculate that the distribution of microorganisms in each medium affects the rate of biodegradation. A large number of microorganisms were attached to the composted food waste and sludge. Mass transfer of VOCs and oxygen to these microorganisms, which appear to have been heterogeneously distributed in clusters, may have been limited, resulting in hindered biodegradation. 相似文献
46.
Hospital wastes are infectious wastes generated in hospitals and need to be disposed in such a way that they do not spread
disease. In this experiment, 5, 10, 15 and 20% cow manure (CM) were mixed with hospital wastes (HW), and mixed wastes were
subjected to vermicomposting. In control treatment, only HW was used for vermicomposting. Results suggested that significantly
(P ≤ 0.05) higher total nitrogen content was recorded in vermicomposts when 10% or more CM was added to HW. Higher mineralization
rate (decrease in C/N ratio) and cellulase activity is probably responsible for rapid organic matter decomposition (loss of
total organic carbon). Ergosterol content i.e., total fungal biomass and cellulolytic fungal population were almost constant
initially, but increased in the latter stage of vermicomposting. All the vermicompost samples, prepared in this experiment,
showed the absence of coliform bacteria. Therefore, it could be concluded that 10% CM addition with HW was the most economical
to obtain best quality vermicompost in terms of nutrient content and microbial status. 相似文献
47.
Young Nam Chun Mun Sup Lim Kunio Yoshikawa 《Journal of Material Cycles and Waste Management》2012,14(1):65-73
A rotary drum dryer having an internal rotating body was designed and tested in this study. It was shown that the developed
dryer is effective for drying sewage sludge. The best operating conditions in the dryer were low energy input and almost 10%
moisture content. The conditions are 255°C for the rotary drum temperature, 17 min for the sludge residence time, and 55 kg/m3 h for the dryer load. Under these conditions, the drying efficiency was 84.8%. The average diameter of dried sludge was less
than 8 mm, and the weight reduction rate was 80%. Parametric screening studies achieved the following results. The drying
efficiency increased with the increase of the internal temperature and the sludge residence time in the rotary drum, while
the drying efficiency decreased when increasing the dryer load. In addition, it was shown that NH3 and CO2 were the primary components released from the sewage sludge drying process. The amounts of both of these components increased
when the rotary drum temperature was increased. 相似文献
48.
Data from surveys conducted by six separate recycling education programs funded under the Clean Michigan Fund are compared. The findings indicate that a strong pro-recycling attitude exists among the populations sampled with a significant percentage of respondents planning to increase their level of recycling in the future. To aid this increase in participation these data suggest that education efforts should focus on helping people become more familiar with the details of how to recycle. And finally, these data support the idea that efforts to promote waste reduction and recycling behavior should focus on non-monetary motives. 相似文献
49.
Marc O. Ribaudo C. Edwin Young 《Journal of the American Water Resources Association》1989,25(1):71-78
ABSTRACT: A framework for estimating the water quality benefits from soil erosion was developed. The framework is based on the linkages between soil erosion and offsite damages. The linkages are: erosion on the field, movement of eroded materials to waterways, impact of discharged material on water quality parameters, impact of water quality changes on ability of water to provide economic services, and the economic value of the changes in water use. These linkages need to be modeled in order to estimate the water quality benefits from reductions in soil erosion. Methods for modeling each link on a geographic level, which enables the analyses of national soil conservation, were examined. Areas where data or models were found to be lacking include transport of sediment and nutrients to water systems, impact of discharged materials on water quality parameters, and impact of water quality on ability of water to provide economic services. An economic evaluation of 1983 soil conservation programs was presented as an example of how the framework could be used. A number of simplifying assumptions were made to represent links that could not be modeled with available data. 相似文献
50.
Peter Wathern Stephen N. Young Ian W. Brown Dawn A. Roberts 《Environmental management》1987,11(1):7-12
The EEC Shellfish Directive is a policy designed to protect and, where necessary, improve the quality of designated shellfish waters. Its implementation within the UK, however, has had no effect upon water quality for two reasons. First, the policy has important defects, having ambiguities concerning public health provisions and lacking designation criteria. Second, UK government has sought to achieve formal compliance, while at the same time ensuring that its full financial impact on public expenditure has been contained. Consequently, only those fisheries which already comply with water quality standards have been designated. Within Wales, one fishery has been designated, while other, commercially more important, but grossly contaminated shellfisheries have not. 相似文献