Heavy metal content of combustible municipal solid waste in Denmark.

Data on the heavy metal composition of outlets from Danish incinerators was used to estimate the concentration of Zn, Cu, Pb, Cr, Ni, Cd, As and Hg in combustible waste (wet as received) at 14 Danish incinerators, representing about 80% of the waste incinerated in Denmark. Zn (1020 mg kg(-1)), Cu (620 mg kg(-1)) and Pb (370 mg kg(-1)) showed the highest concentration, whereas Hg (0.6 mg kg(-1)) showed the lowest concentration. The variation among the incinerators was in most cases within a factor of two to three, except for Cr that in two cases showed unexplained high concentrations. The fact that the data represent many incinerators and, in several cases, observations from a period of 4 to 5 years provides a good statistical basis for evaluating the content of heavy metals in combustible Danish waste. Such data may be used for identifying incinerators receiving waste with high concentrations of heavy metals suggesting the introduction of source control, or, if repeated in time, the data must also be used for monitoring the impacts of national regulation controlling heavy metals. It is recommended that future investigations consider the use of sample digestion methods that ensure complete digestion in order to use the data for determining the total heavy metal content of waste.     

A combined ecosystem and value chain modeling approach for evaluating societal cost and benefit of fishing

We describe a combined ecological and economic approach aimed at giving more equal emphasis to both disciplines, while being integrated so that design, analysis, data entry and storage, and result capabilities are developed with emphasis on deriving a user-friendly, easily accessible tool. We have thus developed the approach as an integrated module of the freely available Ecopath with Ecosim scientific software; the world's most widely applied ecological modeling tool. We link the trophic ecosystem model to a value-chain approach where we explicitly and in considerable detail keep track of the flow (amounts, revenue, and costs) of fish products from sea through to the end consumer. We also describe the social aspects of the fish production and trade, by evaluating employment and income diagnostics. This is done with emphasis on distribution income while accounting for social aspects of the fishing sector. From a management perspective, one of the interesting aspects of the approach we introduce here, is that it opens for direct evaluation of what impact management interventions, e.g., quota settings, effort regulation, or area closures, may have on the ecosystem, the economy and the social setting, as well as on food availability for the consumer.     

Microbial reaction rates and bacterial communities in sediment surrounding burrows of two nereidid polychaetes (Nereis diversicolor and N. virens)

The effects of infaunal mode of life on sediment properties, microbial reaction rates, as well as abundance and composition of bacterial communities were studied in sediment surrounding burrows (mucus lining, oxidised wall, ambient anoxic and surface sediment) of two closely related, but behaviourally different, nereidid polychaete worms: the facultative suspension-feeder Nereis (Hediste) diversicolor and the obligate deposit-feeder Nereis (Neanthes) virens. Burrow sediment of the two species was collected from two adjacent (50 m distance) shallow sandy locations (Kertinge Nor, Denmark). The burrow lining and wall of both polychaete species were enriched in organic matter originating from mucous secretions by the inhabitants and phytoplankton trapped through irrigation. This was more evident for N. diversicolor that shows a significantly higher irrigation rate than N. virens. Both the organic matter mineralisation rates (based on anaerobic incubations) and bacterial abundance were higher along the burrow linings and walls. However, accumulation of porewater TCO₂ and dissolved organic carbon in sediments adjacent to burrows increased most rapidly in the presence of N. diversicolor, suggesting higher heterotrophic activity associated with this species. Surprisingly, bacterial abundance was lower around burrows of N. diversicolor than those from N. virens indicating that burrow environments from the first species harbour a more active bacterial community. Molecular fingerprints of the 16S rRNA gene from bacterial communities showed that the composition of the burrow linings and walls resembled the ambient anoxic sediment rather than the oxic sediment surface. On the other hand, the bacterial fingerprints of the sediment surrounding the burrows of the two polychaete species were markedly different suggesting either a site-specific difference in sediment parameters or a significant species-specific impact of the burrow inhabitants.     

POTENTIAL WATER USE AND AGRICULTURAL PRODUCTION PATTERNS UNDER ALTERNATIVE WATER PRICES1

Out study deals with the demand for water and alternative agricultural production and land use patterns under varying prices for both surface and ground water. We derive irrigation water demands for both the United States and regions of it. Not only is a different amount of water used at each set of water prices but also a different mix of crops, livestock, and production technology develops among the different regions. Under the highest set of prices used, more than fourteen million acres are converted into dryland farming. Total irrigated water use decreases by more than 25 million acre-feet. Irrigated crop yields are reduced and cropping patterns shift away from irrigation. Commodity shadow prices increase as much as 15 percent under high prices for both surface and ground water. A redistribution of farm income occurs between irrigated and dryland regions.     

Work injuries and disability

Problem

This study estimated the hazard ratio for disability pension retirement (DPR) for persons who have experienced a work injury causing absence lasting at least one day after the accidental injury occurred and to estimate the fraction of DPR attributable to work injuries.

Methods:

A total of 4,217 male and 4,105 female employees from a national survey were followed up for subsequent DPR.

Results and impact on industry and government:

Having had a work injury was a strong predictor of DPR among men. After control for age, smoking, body mass index, body postures, and physical demands, the hazard ratio (HR) among those employees who had ever experienced a work injury was 1.80 (95% confidence interval (CI): 1.20-2.68). No association was found among women.

Summary:

Having had a reportable work injury is a strong predictor of subsequent DPR for men.     

The influence of street level bureaucracy on the implementation of Strategic Environmental Assessment

A number of factors are critical to the implementation of measures identified through Strategic Environmental Assessment (SEA) processes. This paper addresses the challenge of implementation from a street level perspective and studies the role of planners and their use of discretion in the SEA implementation process: in which way might planners hinder or facilitate the implementation of SEA? Which coping mechanisms and discretions are deliberately or unconsciously developed and used by the planners? The paper reviews the literature on street level bureaucracy (SLB) in order to identify both factors influencing the implementation behaviour of street level bureaucrats and their coping mechanism when confronted with these factors. Based upon the SLB theory, a case study explores the SLB behaviour involved in the implementation of the SEA of the Copenhagen spatial plan. The analysis shows a surprisingly high level of implementation of measures put forward in the SEA report, and underlines the role of planners at the front line of implementation, functioning as ‘innovators’ during the SEA process and the following implementation of measures. The paper documents the importance of examining planners’ role in SEA and their potential as levers for SEA implementation.     

Trophic State in Voyageurs National Park Lakes before and after Implementation of a Revised Water‐Level Management Plan

We compiled Secchi depth, total phosphorus, and chlorophyll a (Chla) data from Voyageurs National Park lakes and compared datasets before and after a new water‐level management plan was implemented in January 2000. Average Secchi depth transparency improved (from 1.9 to 2.1 m, p = 0.020) between 1977‐1999 and 2000‐2011 in Kabetogama Lake for August samples only and remained unchanged in Rainy, Namakan, and Sand Point Lakes, and Black Bay in Rainy Lake. Average open‐water season Chla concentration decreased in Black Bay (from an average of 13 to 6.0 μg/l, p = 0.001) and Kabetogama Lake (from 9.9 to 6.2 μg/l, p = 0.006) between 1977‐1999 and 2000‐2011. Trophic state index decreased significantly in Black Bay from 59 to 51 (p = 0.006) and in Kabetogama Lake from 57 to 50 (p = 0.006) between 1977‐1999 and 2000‐2011. Trophic state indices based on Chla indicated that after 2000, Sand Point, Namakan, and Rainy Lakes remained oligotrophic, whereas eutrophication has decreased in Kabetogama Lake and Black Bay. Although nutrient inputs from inflows and internal sources are still sufficient to produce annual cyanobacterial blooms and may inhibit designated water uses, trophic state has decreased for Kabetogama Lake and Black Bay and there has been no decline in lake ecosystem health since the implementation of the revised water‐level management plan.     

Nitrogen limitation in the coastal heath at Anholt,Denmark

The purpose of the study was to investigate, whether the coastal grey dune vegetation at Anholt, Denmark, is limited by nitrogen or phosphorus. The island Anholt (22,37 km²) is situated in the centre of Kattegat A two factor fertilization experiment with nitrogen as NH₄NO₃ (N-addition) and phosphorus as KH₂PO₄ (P-addition) was carried out in the coastal grey dune vegetation of Anholt. The N-addition corresponded to 40 kg N ha^?1 year^?1 and the P-addition to 7 kg P ha^?1 year^?1 The experiment included N-, P-, N + P-addition and control. Lichens (genera: mainly Cladonia, Stereocaulon, Cetraria, Hypogymnia) and bryophytes (genera: Polytrichum, Racomitrium) cover most of the surface. Only two plant species, Corynephorus canescens and Empetrum nigrum, constitute nearly all vascular plant cover and biomass of this calcium poor coastal heath community. Corynephorus and Empetrum increased their cover significantly following N and N + P addition. No effect was observed by P addition alone. N limitation of this coastal heath vegetation remote from agricultural and industrial activities was evident. The effect on the plant species of the single application was short-lived. After two-three years of enhanced cover, the Corynephorus and Empetrum cover had returned to their level before the experiment. The lichen vegetation, however, changed more permanently, and after 12 years the subplots with N + P addition was dominated by rich growth of Cladina and Cetraria species. The results are discussed in relation to anthropogenic nitrogen deposition and conservation of this high priority ecosystem.     

垃圾热化学转化利用过程中碳排放的两种计算方法

为了明确城市生活垃圾焚烧和热解两种热化学方式处理过程中温室气体的排放量(简称碳排放或GHG),分别采用生命周期评价方法(LCA)和政府间气候变化专门委员会(IPCC)制定的2006国家温室气体排放清单指南(简称IPCC2006指南)进行了核算,并计算了两种垃圾热化学处理方式相对于填埋处理的GHG减排量.结果表明,两种核算方法计算所得的不同垃圾处理方式的碳排放趋势基本一致,但基于IPCC2006指南计算出的GHG减排量高于LCA方法的计算结果.相对填埋处理而言,焚烧处理的GHG减排量从LCA法的597～660kg(以CO2当量计,下同)提高到IPCC2006指南法的648～747kg;垃圾热解发电的GHG减排量从LCA法的535kg提高到IPCC2006指南法的589kg.同时,对这两种核算方法的特点及在我国的适用性进行了分析,研究认为LCA法和IPCC2006指南可以结合使用以促进我国GHG核算机制的完善.