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1.
This paper uses an event study to examine the transition from federal to state management of the Clean Water Act (CWA). I find that, overall, the transition from federal to state control has little effect on facility compliance, measured by the violation rate. However, states with a long run prevalence of corruption see a large decrease in the violation rate after authorization relative to states without corruption. Alternative specifications support these findings. I explore whether the response to transition to state control differs across political ideology, GDP and income per capita, government size, environmental preferences and government management performance. None of these alternative state level characteristics seem to account for the observed difference. 相似文献
2.
G. Pavlogeorgatos 《毒物与环境化学》2013,95(4-6):159-167
The primal purpose of this research project is to examine the size distribution of the Suspended Solids (SS) of an activated sludge pilot plant, under different operational conditions and during the introduction of wastewater contaminated with mercury of different concentrations (10–100 µg/L Hg(NO3)2). While the experiment was being conducted, the most important parameters of the pilot plant (COD, TOC, MLSS, SS, NH4, PO4, total number of bacteria – coccoids and rods, pH, DO, T etc.) were measured; this fact led to the inference of conclusions that connect the distribution of the size of the SS with those parameters. The main conclusions of this research work are: (a) the important interaction of the removal ability of the organic loading of the plant and the size distribution of the SS at the aeration tank and the outlet of the plant and (b) the input of the mercury-contaminated wastewater at the plant affects the size distribution of the SS at the aeration tank. The second conclusion probably indicates a possible way that microorganisms of the aeration tank react to the introduction of mercury. 相似文献
3.
New legislation for the protection of inland surface waters, transitional waters, coastal waters and ground waters has recently
been established in Italy. This law presents a new integrated approach, where all water bodies are considered as complex ecosystems
to be studied in each of their components. The new concept of environmental quality of the water body, based on the ecological
and chemical status, is also introduced. At the same time (i.e. the end of 2000), the European Community approved the European
Water Framework Directive based on the same basic environmental concepts and criteria of the new Italian law. This paper analyses
the important points and innovations required by the new Italian legislation for monitoring and classification of marine coastal
waters. Details of definitions, parameters, analysis and monitoring programs are discussed. A comparison with the European
Water Framework Directive is eventually given, underlining the specific characteristics of the Mediterranean sea, which have
to be taken into consideration when applying the European Directive to this particular ecoregion. 相似文献
4.
The number and distribution of pollutant concentration in a trapezoidal open channel flow with a side discharge is calculated
and effects of the bank gradient are investigated in this paper. A sigma-coordinate water quality numerical model is used
to simulate the process of both water and pollutant transportation in the trapezoidal channel open flow. The diffusion coefficient
used in the prediction is determined by two methods including constant coefficient and the depth-averaged k-epsilon turbulence
closure model. The change of the concentration with the bank gradient is acquired based on the simulation of cases with different
bank gradients. An analytical formula is derived by using the mirror image method and related diffusion theories, ignoring
the discharge momentum and the influence of the opposite bank. The formula can predict the number and distribution of pollutant
concentration with some acceptable errors. The results demonstrate that the bank gradient has great influence on the concentration
distribution which will decrease with the increase of the bank gradient approximately following a hyperbolic law. 相似文献
5.
Byungjin Lee Eun Seo Jo Dong-Wha Park Jinsub Choi 《Frontiers of Environmental Science & Engineering》2021,15(5):90
6.
Emergy is a thermodynamics-based entity that enables the implementation of a holistic environmental accounting system. It contributes to identify and measure all the inputs (energy and matter) supporting a given system, expressed in a common unit, namely solar emergy joule (sej). The emergy per unit product (called unit emergy value, UEV), is a measure of the environmental cost of a given resource. It is specific of the system/process and gives information on the dynamics, components and functioning of it. This paper presents the emergy evaluation of water resources within the watershed of the river Sieve, located in the Province of Florence (Italy). Along the river, an artificial basin has been created by means of a dam to preserve water quantity and quality, and to protect the Florentine area from dangerous floods and inundations. Different UEVs of water can be identified along the course of the river, especially upstream and downstream of the dam. These values quantify both the environmental and human efforts made to ensure and regulate the presence of water at different points of the river. The UEV of water flowing in the river increases from 1.35 × 105 sej/g upstream, to 5.80 × 105 sej/g downstream of the dam, depending mainly on man-made infrastructure. Along the watershed, three different systems of extraction, purification and distribution of water have been chosen on the basis of their dimension, type and location. UEVs of water distributed and the emergy investment necessary to implement different water management strategies are presented. The value of water purified and distributed decreases from 2.00 × 106 sej/g for the smallest plant in the mountainous area, to 1.72 × 106 sej/g for the largest plant, in the city of Florence, depending on production efficiency. 相似文献
7.
8.
牧草轮作对奶牛场污水氮、磷的净化效果研究 总被引:1,自引:0,他引:1
以土壤为基质,选择象草(Pennisetum purpureum)和黑麦草(Lolium perenne)两种牧草作为植被模拟人工湿地净化系统,研究牧草全年轮作在间歇流人工湿地中对奶牛场高质量浓度污水的适应性及对污水氮、磷的净化效果。结果表明:象草、黑麦草在间歇性高质量浓度污水中生长良好,可作为畜牧场高质量浓度污水修复植物进行全年轮作,并适时的收割,去除污水中的氮、磷。在不同污水质量浓度处理的牧草净化系统中,水力停留时间为8 d的条件下,铵氮的去除率为75.9%~94.9%;硝态氮的去除率为65.4%~90.9%;总氮的去除率64.2%~90.1%;总磷的去除率在90%以上;象草和黑麦草对污水中氮、磷的吸收转化在系统对氮磷净化中的贡献率平均分别为氮25.12%和20.03%、磷31.20%和20.42%;各处理氮、磷的去除效果与污水的质量浓度呈负相关。 相似文献
9.
Jung-Woo Kim Yakov A. Pachepsky Daniel R. Shelton Cary Coppock 《Ecological modelling》2010,221(12):1592-1604
Streambed sediment has been attracting attention as a reservoir for bacteria, including pathogenic strains. Soil and Water Assessment Tool (SWAT) has been augmented with a bacteria transport subroutine in SWAT2005 in which bacteria die-off is the only in-stream process. The purpose of this study was to develop the partial model of sediment-associated bacteria transport in stream and to evaluate the potential significance of streambed Escherichia coli (E. coli) release and deposition within the SWAT microbial water quality simulations. Streambed E. coli release and deposition were simulated based on the sediment resuspension and deposition modules in SWAT. The modified SWAT was applied to the Little Cove Creek watershed, Pennsylvania, which has forestry and dairy pasture landuses. Temporal changes in sediment E. coli concentrations were derived from monitoring data rather than from a streambed bacteria population model. Sensitivity analyses and calibrations were separately conducted for both hydrologic and bacteria parameters. Hydrologic calibration characterized soils in the watershed as pervious and thus the surface runoff was only moderately contributing to the streamflow. However, the surface runoff carried large numbers of E. coli to the stream, and sediment resuspension contributed to the persistent concentration of E. coli in stream water. Although the uncertainty of E. coli concentrations in streambed sediments and from wildlife probably affected the performance of the modified SWAT model, this study qualitatively confirmed the significance of modeling E. coli release from streambed and deposition for the SWAT microbial water quality simulations. Further developments should include modeling dynamics of bacteria populations within streambeds. 相似文献
10.
Feedlots produce a range of trace chemicals that impact human health and/or the environment. The most widely used growth promoter in intensive cattle production in Argentina is monensin, an ionophore polyether with antibacterial and coccidiostatic activity. Several beef cattle feedlots with different management systems, weather conditions, feed types and feedbunk types were selected in different agro-ecological areas of Argentina. Monensin concentrations in samples of pen soil, manure, feed and runoff were analysed. The monensin concentrations measured in soil samples suggest a strong dependence on the type of feed employed in the facility. During feed distribution by trucks to the feedbunks, some feed can reach the soil, thereby increasing the soil monensin concentration close to the feedbunks. The wide range of monensin concentrations detected in manure samples could be explained by the rapid degradation of monensin in the manure matrix. Monensin levels in runoff samples indicated that the distribution of monensin in the environment could be governed by surface phenomena including horizontal movement and adsorption of monensin in particulate material present in the runoff layers. This is the first study of monensin distribution in Argentinian feedlots and serves as the starting point for more sustainable and environmentally friendly feedlot management. 相似文献
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12.
We show that the degradation of phenol by Fe(III) and hydrogen peroxide is faster in the presence of humic acids. This is most likely due to faster reduction of Fe(III)-humate complexes by H2O2/HO2·/O2–· when compared with Fe(III)-H2O complexes. The fact that humic acids, a major class of naturally occurring compounds, favour the Fenton reaction has great relevance in the field of water and soil decontamination, where organic compounds usually have a negative effect. Furthermore, it adds insight into the self-depuration processes of natural aquifers. 相似文献
13.
Modeling the Effect of Population Dynamics on the Impact of Rabbit Hemorrhagic Disease 总被引:1,自引:0,他引:1
CARLOS CALVETE 《Conservation biology》2006,20(4):1232-1241
Abstract: The European wild rabbit ( Oryctolagus cuniculus ) is a staple prey species in Mediterranean ecosystems. The arrival and subsequent spread of rabbit hemorrhagic disease throughout southwestern Europe, however, has caused a decline in rabbit numbers, leading to considerable efforts to enhance wild rabbit populations, especially through habitat management. Because rabbit population dynamics depend on habitat suitability and changes in habitat structure and composition subsequent to habitat management, I evaluated the effects of population dynamics on the long-term impact of rabbit hemorrhagic disease on rabbit populations. I used an age-structured model with varying degrees of population productivity and turnover and different habitat carrying capacities, and I assumed the existence of a unique, highly pathogenic virus. My results suggest that disease impact may be highly dependent on habitat carrying capacity and rabbit population dynamics, and the model provided some insight into the current abundance of wild rabbits in different locations in southwestern Europe. The highest disease impact was estimated for populations located in habitats with low to medium carrying capacity. In contrast, disease impact was lower in high-density populations in habitats with high carrying capacity, corresponding to a lower mean age of rabbit infection and a resulting lower mortality from rabbit hemorrhagic disease. The outcomes of the model suggest that management strategies to help rabbit populations recover should be based on improving habitats to their maximum carrying capacity and increasing rabbit population productivity. In contrast, the use of strategies based on temporary increases in rabbit density, including vaccination campaigns, translocations, and temporal habitat improvements at medium carrying capacities, may increase disease impact, resulting in short-term decreases in rabbit population density. 相似文献
14.
控制稻田甲烷排放的农业耕作条件的研究 总被引:1,自引:0,他引:1
在1990—1992年期间中国环境科学研究院观测了北京地区洼里乡的稻田中甲烷的排放情况。其间农田中施用了有机堆肥和几种化学肥料,以观察化学肥料和有机肥料对甲烷排放的影响。结果显示,在通常的农业耕作条件下本地区甲烷排放水平为17.6mg/m~2·h,并且在整个生长期中间有两个排放高峰,高峰期甲烷排放量占全年排放总量的65%以上,试验结果还显示有机肥料具有增加甲烷排放的作用;化学肥料,如硫胺、尿素等,在其有效作用期间,有抑制甲烷排放的作用,间歇灌溉是有效控制甲烷排放的方法之一。 相似文献
15.
Obiri-Danso Kwasi Jones Keith Jones Keith Paul Nigel 《Journal of Coastal Conservation》1999,5(1):51-58
The ability of Morecambe’s three designated bathing waters to pass the EU Directive on Bathing Water Quality depends on the
time of day when the sample is taken, the indicator organism tested for and whether the test uses the most strict (Guideline)
or the least strict (Imperative) criteria. Morning and afternoon sampling for faecal coliforms, faecal streptococci and the
pathogenCampylobacter was carried out monthly over the 1996 and 1997 bathing seasons. In the afternoons average faecal coliforms declined by 77%
in 1996 and 87% in 1997 compared with the mornings, faecal streptococci by 79% and 83% and campylobacters by 66% and 86%.
This decline in bacterial numbers between morning and afternoon was related to variations in water temperature and levels
of ultraviolet radiation. All three bathing waters failed the Guideline criteria of the EU Directive on Bathing Water Quality.
Using the Imperative criteria, no bathing waters passed in the mornings of either year, some passed in the afternoons of 1996
and all passed in the afternoons of 1997. The increased pass rate in 1997 coincided with improved sewage treatment, high temperatures
and increased levels of sunshine. In 1997 sampling by the Environment Agency produced fewer failures than our morning sampling
but more than our afternoon sampling. Their sampling was done around midday. It is suggested that where possible all sampling
of EU designated bathing waters should be carried out in the early morning. 相似文献
16.
Jun Li Wentao Li Gan Luo Yan Li Aimin Li 《Frontiers of Environmental Science & Engineering》2019,13(1):6
17.
Jinjin Fu Quan Zhang Baocheng Huang Niansi Fan Rencun Jin 《Frontiers of Environmental Science & Engineering》2021,15(1):17
18.
Discharges of nutrients, urea, dissolved organic matter and heavy metals by a sewage underwater pipeline are analysed in comparison to environmental conditions in a shallow coastal zone. Variable thermo-haline stratifications of the water column and currents in upper (2.62-34.97 cm s-1) and deeper (0.83-10.91 cm s-1) layers drive vertical diffusion and lateral transport of wastewaters. Loads of reactive phosphorus (0.13 tons d-1) and ammonium (1.62 tons d-1) by the pipeline are not negligible compared to the major river loads in the gulf. High concentrations of urea (≤11.51 μmol N dm-3) were found in the area of wastewater release. Ammonium uptake (6.14-534 nmol N dm-3 h-1) strongly exceeded nitrate uptake (0.19-138 nmol N dm-3 h-1), indicating that discharges of ammonium by the pipeline are actively assimilated by plankton community even at low levels of light. Distribution of Zn (≤27.7 ppb), Cu (≤25.6 ppb), Cd (≤0.80 ppb) and Pb (≤13.5 ppb) in the water column and the measurement of their complex-forming capacity in seawater did not indicate a persistent perturbation of the pelagic environment due to heavy metals. 相似文献
19.
Samal Kaumbekova Mehdi Amouei Torkmahalleh Naoya Sakaguchi Masakazu Umezawa Dhawal Shah 《Frontiers of Environmental Science & Engineering》2023,17(2):15
20.
The Convention on Biological Diversity has catalyzed worldwide awareness of threats to biological diversity and stimulated global conservation strategies. These have led to national and international legislation and have generated debate about the most effective conservation actions. Under the EU Habitats Directive, all member states are obliged to establish a system for strict protection of species listed in Annex IV(a), which includes all bats. In England, this obligation has resulted in legislation that allows for derogation from strict protection under license, provided activities are undertaken to mitigate any potential negative effects on bat numbers. We used an evidence‐based approach to assess the cost‐effectiveness of mitigation strategies and the English bat‐derogation licensing process as a whole. We analyzed data from 389 bat derogation licenses issued in England from 2003 to 2005 relating to 1776 roosts and 15 species to determine the nature and extent of development and mitigation activities and their effects on bats. Overall the effects of licensed activities on roosts were negative. Despite the level of protection afforded to bats, the majority (68%) of roosts for which derogation licenses were issued were destroyed. There were species‐specific differences in the probability of roosts being destroyed, and impacts on roosts did not reflect a species’ conservation status. Information provided by licensees was inadequate and inconsistent. Most licensees (67%) failed to submit postdevelopment reports, and postdevelopment monitoring was conducted at only 19% of sites. Despite a minimum of £4.13 million spent on mitigation structures for bats from 2003 to 2005, it was unclear whether the licensing process meets EU obligations. On the basis of our results, we believe there is a need to overhaul the licensing process, to establish a comprehensive, standardized postdevelopment monitoring system, and to demonstrate that mitigation is commensurate with Britain's legal obligations. Mitigando el Efecto del Desarrollo sobre los Murciélagos en Inglaterra con Licencias de Derogación 相似文献