The Influence of Anthropogenic Contamination On Metals Release From Coastal Sediment Suspensions with Aerated Sea Water

The zinc, cadmium, copper and lead release from the uncontaminated and contaminated coastal sediments with aerated sea water was studied. the metals transfer to the dissolved forms was monitored during one-two months by differential pulse anodic voltammetry (DPASV). the sediments with different initial degree of contamination were sampled in the Peter the Great Bay, Sea of Japan around Vladivostok-the biggest city in Russian Far East. Sediment contamination by metals led to increased release to solution of zinc due to sulphide oxidation and cadmium on account of organic matter decomposition. the copper behaviour was complicated by strong binding with organic matter and enhancements of copper release can only be seen in sediment with a low organic matter content. Significant lead transfer to dissolved forms was not observed regardless of sediment contamination. the temperature affected the release of cadmium and copper through enhanced organic matter destruction. the dissolved metal fluxes from the sediment transformation are compared with metal fluxes towards bottom. Such comparisons show that second contamination by dissolved metals of the studied coastal environment may be important for cadmium only.     

Organic Contaminants from Sewage Sludge Applied to Agricultural Soils. False Alarm Regarding Possible Problems for Food Safety? (8 pp)

Goal, Scope and Background Sewage sludge produced in wastewater treatment contains large amounts of organic matter and nutrients and could, therefore, be suitable as fertiliser. However, with the sludge, besides heavy metals and pathogenic bacteria, a variety of organic contaminants can be added to agricultural fields. Whether the organic contaminants from the sludge can have adverse effects on human health and wildlife if these compounds enter the food chain or groundwater still remains a point of controversial discussion. Main Features This paper presents an overview on the present situation in Europe and a summary of some recent results on the possible uptake of organic contaminants by crops after addition to agricultural fields by sewage sludge. Results Greenhouse experiments and field trials were performed to study the degradation and uptake of organic micro-contaminants in sludge-amended agricultural soil in crops, such as barley and carrots grown in agricultural soil amended with anaerobically-treated sewage sludge from a wastewater treatment plant, but studies hitherto have revealed no immediate risks. Common sludge contaminants such as linear alkylbenzene sulphonates (LAS), nonylphenol ethoxylates (NPE), polycyclic aromatic hydrocarbons (PAH), bis(diethylhexyl) phthalate (DEHP), showed neither accumulation in soil nor uptake in plants. Discussion It is assumed that the annual amount of sewage sludge produced in Europe will increase in the future, mainly due to larger amounts of high quality drinking water needed by an increasing population and due to increasing demands for cleaner sewage water. Application of sewage sludge to agricultural soils is sustainable and economical due to nutrient cycling and disposal of sewage sludge. However, this solution also involves risks with respect to the occurrence of organic contaminants and other potentially harmful contents such as pathogens and heavy metals present in the sludge. There have been concerns that organic contaminants may accumulate in the soil, be taken up by plants and thereby transferred to humans via the food chain. Results obtained so far revealed, however, no immediate risk of accumulation of common organic sludge contaminants in soil or uptake in plants when applying sewage sludge to agricultural soil. With very high dosages of sewage sludge, there may be a risk for accumulation of very apolar contaminants, such as DEHP, to the soil. Conclusions Any conclusions on the safe use of sewage sludge in agriculture have to be drawn carefully, as the studies performed until now have been limited. Further studies are required, and before final statements can be drawn, it is imminent to study a larger variety of common crops and the effect sewage sludge application may have on a possible accumulation of organic contaminants in the crops. Furthermore, a larger variety of organic contaminants need to be studied and special focus should be given to contaminants newly introduced into the environment. Besides investigating possible plant uptake of organic contaminants, the fate of these compounds in soil after sludge application need to be monitored too. Here, special attention has to begiven to studies on degradation and the formation of degradation products, to weathering and to leaching effects on groundwater, to the application of different crops on the same field (crop rotation), to the use of full-width tillage and strip tillage, and to long term application of sewage sludge on the soil. Recommendations and Perspectives There are environmental, political as well as economical incentives to increase the agricultural application of sludge. However, such usage should be performed with care as there are also ways in which sludge fertilisation could harm the environment and human health. Recently, a new European COST Action (859) has been established covering the field of food safety and improved food quality. Part of the Action is dealing with the application of sewage sludge in agriculture. Before any political and economical measures can be taken, the pros and cons have to be sufficiently investigated on a scientific level first. ESS-Submission Editor: Prof. Elena Maestri (elena.maestri@unipr.it)     

Estimating the non-market benefits of climate change adaptation of river ecosystem services: A choice experiment application in the Aoos basin,Greece

Mountains are important global reservoirs of water resources. However they are highly vulnerable to climate change as limited alterations in temperature and precipitation may cause harmful effects to water systems. Southern Europe and especially Greece are expected to undergo a drought trend over the next decades, resulting in less recharge for the aquifers and water services reduction. Thus, climate change may distort both natural and socioeconomic characteristics of freshwater ecosystem services deteriorating the general social welfare related to them. This paper examines the economic impacts of climate change on river uses of the Aoos basin in Greece. In this regard, a choice experiment is conducted to estimate the value changes in different ecological and economic services in a mountain community. The econometric simulations using conditional logit, random parameters logit and latent class models reveal that despite existing preference heterogeneity, respondents on average derive positive and significant welfare effects from climate change adaptation measures. The findings of the survey may assist in adaptation planning for the Aoos River basin, with possible extensions to other river systems enduring similar climate change indications.     

Adoption of irrigation water policies to guarantee water supply: A choice experiment

More efficient and sustainable use of water is increasingly becoming an urgency in drought prone parts of the world. In particular, in water scarce regions such as the Mediterranean, water supply is expected to become more uncertain because of climate change. Consequently, pro-active policy initiatives are proposed to increase supply reliability. Local context is important when the effectiveness of policies is assessed. The aim of this paper is to evaluate farmers’ acceptance of policy strategies to increase water supply reliability in the Segura, a water scarce river basin in the south-east of Spain. Results from a choice experiment suggest that farmers are willing to pay twice as much as their current irrigation water price to ensure water supply reliability through government supply guaranteed programs. However, they are averse to any institutional changes that might assist the government to achieve increased water supply.     

水质模型参数优化的遗传算法实现及控制参数分析

参数识别是数学模型应用的前提.遗传算法是一种通用的全局优化算法,结构简单.一个实际应用问题能否利用遗传算法解决,关键在于遗传算法的设计和控制参数的选取.本文结合水质模型参数优化的特点,提出采用正交试验设计的方法来考察遗传算法不同控制参数对参数优化性能的影响,结果显示,正交法较好地识别了关键影响因素,并提出可能的最优方案.表明遗传算法能较好地应用于复杂多参数水质模型的参数识别研究.     

Graduated stringency within collective incentives for group environmental compliance: Building coordination in field-lab experiments with artisanal gold miners in Colombia

Small-scale gold mining is important to rural livelihoods in the developing world but also a source of environmental externalities. Incentives for individual producers are the classic policy response for a socially efficient balance between livelihoods and the environment. Yet monitoring individual miners is ineffective, or it is very costly, especially on frontiers with scattered small-scale miners. We ask whether monitoring at a group level effectively incentivizes cleaner artisanal mining by combining lower-cost external monitoring with local collective action. We employ a mining-framed, threshold-public-goods experiment in Colombia's Pacific region, with 640 participants from frontier mining communities. To study compliance with collective environmental targets, we vary the target stringency, including to compare increases over time in the stringency versus decreases. We find that collective incentives can induce efficient equilibria, with group compliance – and even inefficient overcompliance – despite the existence of equilibria with zero contributions. Yet, for demanding targets in which the reward for compliance barely outweighs the cost, compliance can collapse. Those outcomes improve with past successes for easier targets, however, so our results suggest gain from building coordination via graduated stringency.     

Modelling the propagation of an internal solitary wave across double ridges and a shelf-slope

Evolution of the internal solitary waves (ISWs) in the northern South China Sea (SCS) has recently attracted the attention of many oceanographers in Taiwan and the United States. These ISWs are believed to have been induced by a branch of the Kuroshio current over Luzon Strait, which propagates westward over two ridges in the Luzon Strait between Taiwan and the Philippines, and further onto the continental margin with a shelf-slope in the SCS. This paper presents some preliminary results for the evolution of a depression ISW across two triangular obstacles using numerical modelling and laboratory experiments. The experimental results confirm that the intervals and relative height between the two obstacles are important factors in the interaction of an ISW with the obstacles. However, in the case of the movement of an ISW of depression-type across the Luzon Strait, the effect of the two ridges on the characteristics of the ISW might be less significant than that from the shelf-slope, due to the variations in relative water depth. Results from numerical experiments also show that the amplitude of an ISW can be augmented once the wave commences its contact with a shelf-slope, where an internal hydraulic jump and wave breaking with vortex motion are evident in the laboratory experiments. Eventually, an ISW of depression-type could become an elevation-type at the edge of the continental shelf landwards beyond the turning point, where the upper layer is larger than the bottom layer in a stratified water column.     

Chelant-assisted pulse flushing of a field Pb-contaminated soil

Laboratory experiments on a lead-contaminated soil were carried out to test the effects of chelant addition on metal leachability using column tests. Tests were aimed at studying metal mobilisation upon application of two different chelating agents (ethylenediaminetetraacetic acid [EDTA] and ethylenediaminedisuccinic acid [EDDS]). Column operation was arranged to simulate a flushing treatment in which the chelating agent is applied in a pulse mode to the soil for one bed volume, while deionised water was continuously introduced for the rest of the experiment. Two different concentrations (3 and 5 mmol·kg ^?1 respectively) of the two chelating agents and a control solution (deionised water) were tested in separate experiments; pH, total organic carbon and the total concentrations of Pb, Zn, Fe, Cd, Cu and Ni were monitored during each run. A seven-step sequential extraction procedure was used to evaluate metal partitioning and concentration in the contaminated soil after treatment as a function of depth. The results showed the effect of the nature of flushing solution on the hydraulic behaviour of the columns. Metal concentrations in the leachate increased considerably upon the application of chelants, thus indicating their suitability for metal extraction from contaminated soils. In view of full-scale application of soil flushing, particular concern should also be devoted to ensuring a homogeneous distribution of the solution within the contaminated area and an efficient collection of the exhausted extracting solution, as well as to recovering and recycling the chelating agent used.     

Terrestrial perturbation experiments for environmental assessment

The National Environmental Policy Act of 1969 (NEPA) was initially interpreted as requiring full disclosure of the environmental impact of a federal action. Because of the limitations of time, money, and manpower, the requirement that all impacts be considered has led to superficial analysis of many important impacts. Data collection has largely been limited to the enumeration of species because this information can be applied to the analysis of any problem. The President's Council on Environment Quality (CEQ) has provided a solution to this problem by reinterpreting NEPA as requiring analysis of those impacts that have significant bearing on decision making. Because assessment resources can now be concentrated on a few critical issues, it should be possible to perform field perturbation experiments to provide direct evidence of the effects of a specific mixture of pollutants or physical disturbances on the specific receiving ecosystem. Techniques are described for field simulation of gaseous and particulate air pollution, polluted rain, soil pollutants, disturbance of the soil, and disturbance of wildlife. These techniques are discussed in terms of their realism, cost, and the restrictions that they place on the measurement of ecological parameters. Development and use of these field perturbation techniques should greatly improve the accuracy of predictive assessments and further our understanding of ecosystem processes.Research sponsored by the Office of Health and Environmental Research, U.S. Department of Energy, under contract W-7405-eng-26 with Union Carbide Corporation.Publication No. 1816, Environmental Sciences Division, ORNL.     

碳纤维增强尼龙复合材料低温环境适应性试验设计与分析

目的设计碳纤维增强尼龙复合材料低温环境适应性试验,分析低温环境中材料性能变化特征和老化规律,研究该材料在低温条件下的环境适应性。方法选取碳纤维增强尼龙复合材料的冲击强度为主要表征指标,对制备的缺口冲击试样开展-50℃低温试验和寒冷低温气候的自然环境试验,定期测试其冲击强度性能,分析各试验条件下力学性能特征和老化趋势。结果低温条件下碳纤维增强尼龙复合材料会发生明显脆化,表现为冲击强度下降达40%以上,而从低温恢复到常温状态,该材料性能亦会恢复到稳定值附近。结论针对碳纤维增强尼龙复合材料在低温环境下的环境适应性,其低温使用时抗冲击能力会明显下降,出现"脆化"现象,但该材料低温贮存性能较为优异,结合自然环境试验结果,可认为,低温环境下该材料具有较好的环境适应性。