Quantification of the resource recovery potential of municipal solid waste incineration bottom ashes

Municipal solid waste incineration (MSWI) plays an important role in many European waste management systems. However, increasing focus on resource criticality has raised concern regarding the possible loss of critical resources through MSWI. The primary form of solid output from waste incinerators is bottom ashes (BAs), which also have important resource potential. Based on a full-scale Danish recovery facility, detailed material and substance flow analyses (MFA and SFA) were carried out, in order to characterise the resource recovery potential of Danish BA: (i) based on historical and experimental data, all individual flows (representing different grain size fractions) within the recovery facility were quantified, (ii) the resource potential of ferrous (Fe) and non-ferrous (NFe) metals as well as rare earth elements (REE) was determined, (iii) recovery efficiencies were quantified for scrap metal and (iv) resource potential variability and recovery efficiencies were quantified based on a range of ashes from different incinerators. Recovery efficiencies for Fe and NFe reached 85% and 61%, respectively, with the resource potential of metals in BA before recovery being 7.2%ww for Fe and 2.2%ww for NFe. Considerable non-recovered resource potential was found in fine fraction (below 2 mm), where approximately 12% of the total NFe potential in the BA were left. REEs were detected in the ashes, but the levels were two or three orders of magnitude lower than typical ore concentrations. The lack of REE enrichment in BAs indicated that the post-incineration recovery of these resources may not be a likely option with current technology. Based on these results, it is recommended to focus on limiting REE-containing products in waste for incineration and improving pre-incineration sorting initiatives for these elements.     

瑞典维纳恩湖的沉积物和鱼类种群中的汞:污染后的恢复状况

过去流入维纳恩湖的含汞废水颇多.通过连续测定沉积物和鱼体中的汞来监测其影响和恢复状况.汞的主要源头来自湖北岸的一座氯工厂.尽管60年代从源头流出的废水中汞水平有了根本性的减少,附近湖泊沉积物中汞的水平从70年代中期以来只下降了一半多.狗鱼(Esox lucus)体内汞的水平在同期下降的幅度相似.湖泊受影响最大的部分比受影响最小的部分要高出30%.湖泊中的鲈鱼(Percafhviatilis)和三文鱼鱼体内汞水平不高.尽管维纳恩湖沉积物中汞水平有所增加,比起位于同一地区而没有受当地汞废水污染湖泊内的鱼来说,维纳恩湖鱼体内汞的水平相对来说并不算高.据估算,湖内鱼类总生物量所含的汞不到湖泊底部沉积物上层活性生物层所含汞总量的千分之一.这显示了各种环境因子的潜在影响,并促使我们将来要继续对汞水平进行监测.     

环境监测策略评价

在环境监测中,监测系统在非预期事件出现时能够发出早期预警是很重要的.这些事件具有突发,或者难以观测到的性质.在设计这类监测系统时,必须在成本和风险之间达到一个适当的平衡.传统意义上有两类和早期预警系统相关联的风险,即没有检测到重要变化的风险和错误预警的风险.本文的目的是阐述一种在考虑了传统类型的风险和成本的情况下来比较不同监测系统性能的方法.这个方法被试用于地衣植被的监测中,并采用预期效应作为性能的度量标准.在估计事件的概率时,应用了空间微观模拟技术(spatial microsimulation)和蒙特卡罗模拟技术.所评估的监测计划基于卫星图像、航空照片、野外采样和土地覆被图.研究的主要结论是,标准化质量度量在环境监测方法可用性的评估中是极为有用的.另外,空间微观模拟技术在效益和成本估计中是可用的.不过要改进算法,还需要应用宏观约束(macroconstraints)来修正模拟模型.     

雄性波罗的海灰海豹(Halichoerus grypus)骨组织的矿物密度

本文利用非侵入计算层析X射线摄影法(pQCT)研究了雄性波罗的海灰海豹(4～23岁龄)骨组织的矿物密度(mg/cm3).资料按照收集的年份分组.A组1850～1955年,有机氯(OCs)大量引入之前的时期;B组1965～1985年,OC污染十分严重的时期;C组1986～1997年,OCs浓度逐渐减小的时期.测量结果的复现性良好,变异系数(CV)为0.1%～2.1%.1986～1997年收集的标本中桡骨小梁的矿物密度比1965～1985年收集的标本的明显要高(p＜0.05).1986～1997年收集的标本中,下颌骨的皮层骨矿物密度明显地低于1850～1955年收集的标本(p＜0.05).这些结果表明小梁和皮层骨在一段时间内的不同响应.在OC污染非常严重的时期(1965～1985年),小梁骨矿物密度最低,而在1985～1997年收集的标本中,皮层骨密度最低,该时段是一个OC污染程度相当低的时期.有关这些效应背后的机制目前尚不知道.但是,可以假定这里涉及到OCs.由于目前缺乏有关研究个体中OCs残留水平的资料,因此不可能评估OCs在这方面的影响.     

Rival recognition affects male contest behavior in sand lizards (Lacerta agilis)

Individual male sand lizards meet repeatedly during mate search and engage in costly interactions. If males can recognize rivals, the number of costly fights with a predictable outcome may be reduced. In staged contests between males, second interactions are on average significantly shorter than first ones, suggesting individual recognition. When aggressive behavior differs substantially between the sexes, the more aggressive sex may be predicted to have more variation in skin traits located on the parts of the body displayed during contests; this would facilitate individual recognition. Male (aggressive) sand lizards are more variable in two of three lateral skin traits displayed during males' contests, while females (non-aggressive) are more variable in one dorsal skin trait; in four other dorsal traits there was no difference in variability between the sexes.     

Species-specific antipredator capacities and prey refuges: interactions between piscivorous perch (Perca fluviatilis) and juvenile perch and roach (Rutilus rutilus)

The outcome of predator-prey interactions depends on the characteristics of predators and prey as well as the structure of the environment. In a replicated field enclosure experiment, we tested the effects of quantity and quality of different prey refuges (no structure, structure forming a partial refuge, and structure forming a complete refuge) on the interaction between piscivorous perch (Perca fluviatilis) and juvenile perch and roach (Rutilus rutilus). We quantified the behaviour of the predators and the prey and predator-induced prey mortality. The piscivores stayed in or close to the prey refuge and were more dispersed in the presence than in the absence of prey refuges. Survival of juvenile perch and roach decreased in the presence of predators and was higher for juvenile roach than for juvenile perch. In addition, juvenile perch survival increased with refuge efficiency Roach formed schools which were denser in the presence of predators, had a higher swimming speed (both in the open water and in the refuge) and used a larger area than juvenile perch. Both prey species decreased their distance to the prey refuge and increased the proportion of their time spent in the refuge in the presence of predators. The number of switches between the open-water habitat and the prey refuge was higher for juvenile roach than for juvenile perch. Juvenile perch used different parts of the prey refuge in a flexible way depending both on presence of predators and refuge type whereas juvenile roach used the different parts of the prey refuge in fixed proportions over all refuge treatments. Our results suggest that juvenile roach had a overall higher capacity to avoid predation than juvenile perch. However, in the presence of qualitatively different prey refuges juvenile perch responded to predators with more flexible refuge use than juvenile roach. The differences in antipredator capacities of juvenile perch and roach when subjected to piscivorous perch predation may depend on differences in life history patterns of the two species.     

Screening life cycle assessment (LCA) of tomato ketchup: a case study

A screening life cycle assessment (LCA) of tomato ketchup has been carried out. The purpose was to identify ‘hot-spots', that is parts of the life-cycle that are important to the total environmental impact. The system investigated includes agricultural production, industrial refining, packaging, transportation, consumption and waste management. Energy use and emissions were quantified and some of the potential environmental effects assessed. Packaging and food processing were found to be hot-spots for many, but not all, of the impact categories investigated. For primary energy use, the storage time in a refrigerator (household phase) was found to be a critical parameter.     

A one year study of the seasonal variations of sDDT and PCB levels in fish from heated and unheated areas near a nuclear power plant

An investigation of the influence of excess heat discharge from a nuclear power plant on the residual levels of the sDOT and PCB in roach and perch has been made during a period of one year. A seasonal variation of the residual concentrations was observed, with the highest levels during spring and early summer and lower more stable levels in the autumn. Significantly higher levels of the sDDT and PCB was observed in perch from the cooling water recipient as compared to values in perch from the intake area. No significant differences could however be verified for roach. The result stress the importance that, in a monitoring program, a sampling period with stable ecological conditions is selected.     

Evaluation of environmental monitoring strategies

In environmental monitoring, it is important that the monitoring system should emit early warnings when undesired events occur. These events may be sudden or of a more subtle nature. In the design of such monitoring systems, a proper balance between cost and risk must be achieved. There are 2 classic types of risk connected with early warning systems, namely the risk of not detecting significant changes and the risk of false alarms. The purpose of this paper is to describe a method for comparing the performance of different monitoring systems, considering the classic types of risk and cost. The method is applied to the monitoring of the lichen cover as a test case. The expected utility has been used as a measure of performance. When estimating the probabilities of the events, spatial microsimulation and Monte-Carlo simulation techniques have been used. The monitoring programs studied are based on satellite images, aerial photos, field samples, and land-cover maps. The major conclusions of this study are that standardized quality measures are extremely useful for evaluating the usability of environmental monitoring methods. In addition, when estimating gains and costs, spatial microsimulation techniques are useful. To improve the method, however, macroconstraints should also be used for aligning the simulation model.     

Economic valuation for sustainable development in the Swedish coastal zone

The Swedish coastal zone is a scene of conflicting interests about various goods and services provided by nature. Open-access conditions and the public nature of many services increase the difficulty in resolving these conflicts. "Sustainability" is a vague but widely accepted guideline for finding reasonable trade-offs between different interests. The UN view of sustainable development suggests that coastal zone management should aim at a sustainable ecological, economic, and social-cultural development. Looking closer at economic sustainability, it is observed that economic analyses about whether changes in society imply a gain or a loss should take into account the economic value of the environment. Methods used for making such economic valuation in the context of the Swedish coastal zone are briefly reviewed. It is noted that the property rights context matters for the results of a valuation study. This general background is followed by a concise presentation of the design and results of four valuation studies on Swedish coastal zone issues. One study is on the economic value of an improved bathing water quality in the Stockholm archipelago. The other studies are a travel cost study about the economic value of improved recreational fisheries in the Stockholm archipelago, a replacement cost study on the value of restoring habitats for sea trout, and a choice experiment study on the economic value of improved water quality along the Swedish westcoast.