Trends in natural-resource commodity prices: An analysis of the time domain

This paper attempts to reconcile the theoretical predictions of increasing real prices for nonrenewable natural-resource commodities obtained from Hotelling-style models with the empirical findings of falling prices for these commodities. A theoretical model for relative-price movements is derived for the case of exogenous technical change and endogenous change in the grade of ores mined. The model suggests a U-shaped time path for relative prices. The implied price movements are tested for all the major metals and fuels and the model parameters are found to be statistically significant for 11 out of the 12 commodities tested.     

Concentrations of selected metals in chicken eggs from commercial farms in Southern Nigeria

This work presents the results of the determination of concentrations of the trace metals Ni, Zn, Mn, Pb, Cd, Cr, Co, Cu, and Fe in eggs from farms in Southern Nigeria. The mean concentrations (µg?g^?1 fresh weight) ranged from 0.6 to 1.2 for Ni, 3.1 to 8.9 for Zn, 0.45 to 0.65 for Mn, 0.4 to 1.2 for Pb, <0.09 to 0.3 for Cr, 0.1 to 0.3 for Cd, 0.26 to 0.34 for Co, 0.9 to 1.2 for Cu and 19.5 to 24.0 for Fe. The concentrations and estimated dietary intakes of these metals were below the respective statutory limits. The Target Hazard Quotient (THQ) values for the individual metals in all zones are less than 1, i.e., within safe levels. The combined THQ values for the different zones were greater than 1but less than 2, with a significant contribution of cobalt.     

桉树人工林生态系统养分循环与平衡研究Ⅳ.桉树林间种山毛豆对生态系统养分循环的作用

桉树人工林间种山毛豆，增加了凋落物量和养分归还量，改善了营养元素的生物小循环。在一个轮伐期内山毛豆归还土壤养分的数量如下：氮528.37kg／hm^2，磷28.06kg／hm^2，钾66.20kg／hm^2，钙184.96kg／hm^2，镁57.21kg／hm^2；而同期刚果W5桉归还土壤养分的数量为：氮85.98kg／hm^2，磷3.94kg／hm^2，钾11.80kg/hm^2，钙36.98kg／hm^2，镁18.30kg／hm^2。由于间种山毛豆增加了生态系统的养分收入，减少了水土流失的养分支出，系统的各种养分出现了盈余的状况。     

可持续发展战略的环境保护行动

从可持续发展论释义,以及以污染现实反证,提出环境是可持续发展的基础,保护环境就是保护人类社会赖以生存和发展的自然资源,自然资源是发展的根本条件的论点,进而提出环境保护工作的二项基本任务。依此提出可持续发展战略的环境保护行动框架意见。     

Relationship between total concentration and dilute HCl extraction of heavy metals in sediments of harbors and coastal areas in Korea

Total concentrations of Cr, Ni, Cu, Zn, Cd and Pb in surface sediments were determined to investigate the regional trends of heavy metal contamination in 11 coastal areas in Korea. Enrichment factor (EF) of heavy metals was calculated by comparing the level of their regional background. The averages of EF values in study areas were 0.99 for Cr, 1.05 for Ni, 4.23 for Cu, 1.80 for Zn, 3.92 for Cd and 1.54 for Pb, respectively. Dilute HCl extractions were useful to deduce the anthropogenic sources of heavy metals and the 1 M HCl extractable fractions of each metal varied from 0.3 to 37.3% for Cr, 1.9 to 66.3% for Ni, 4.2 to 92.9% for Cu, 7.1 to 99.7% for Zn, 10.9 to 98.9% for Cd and 15.0 to 99.1% for Pb. Comparing 1 M HCl extractable fraction to total concentration, large portions of Cu, Zn, Cd and Pb were present as potentially bioavailable fractions from anthropogenic input and were significantly correlated with their EF values showing r > 0.68.     

A set of associated statistical tests for spatial clustering

The purpose of this paper is to develop a set of associated statistical tests for spatial clustering. In particular, a set of three associated tests will be developed; these will correspond to the three types of tests set out by Besag and Newell (general tests, focused tests, and tests for the detection of clustering). The associated tests draw primarily, though not exclusively, upon existing tests and results. The principal contributions are based upon the score statistic for focused tests, which has been an important approach to testing for clustering around environmental hazards. The first contribution consists of the formulation of a global statistic for general tests that corresponds to focused score statistics, along with an assessment of the distribution of the statistic under the null hypothesis of no raised incidence. The local score statistics used for focused tests will have the property of summing to the global statistic used for the corresponding general test. Attention is also given to the maximum local score statistic for the “test for the detection of clustering”. The critical values of this statistic which are required for testing the null hypothesis are described. Application of the methods is made to leukemia data for central New York State.     

Priority-Setting Tool Applied to Canada's Landbirds Based on Concern and Responsibility for Species

Abstract: As a contribution to Partners in Flight–Canada, the Canadian Wildlife Service developed a ranking system to help set priorities for landbird species. Two complementary species lists were generated: one with scores for "concern" representing vulnerability and population trend, and one for "responsibility" for regionally characteristic fauna. The concern score gave equal weight to vulnerability, a composite score based on abundance and breadth of range, and population trend, because its purpose was to give early warning of potential problems. Responsibility scores were scale-free and were assigned for the season in which the species is most abundant. Other systems for identifying species of concern may be more appropriate for other jurisdictions or organisms, but the responsibility ranking is widely applicable. This system is a coarse filter that generates preliminary ranks; additional information should be considered in deciding how to allocate scarce resources for conservation. Unrefined results are nonetheless useful for a variety of purposes, as illustrated by the scores for Canadian landbirds. About 25% of Canada's high-responsibility species are also of high concern. These high-concern species are not associated with specific habitats or migration patterns. Conservation of species ranking high on concern and responsibility merits cooperation with the United States and Mexico in particular. The scores identified improved monitoring as a priority conservation activity for Canada.     

Lethal levels of hypoxia for gulf coast estuarine animals

There is increasing concern about eutrophication and subsequent hypoxia problems in estuaries. The US Environmental Protection Agency has developed Water Quality Criteria (WQC) for dissolved oxygen (DO) in saltwater for Cape Cod, MA to Cape Hatteras, NC but inadequate data exists for development of such criteria for other coastal geographic areas. We performed acute tests with two species of crustaceans and seven species of estuarine fishes native to the Gulf of Mexico to complement the data base for northeastern species. Flow-through tests were conducted for either 24- or 48-h at test temperatures from 24 to 28°C and at salinities from 20 to 31.5‰. Estimated 24-h LC50 values obtained for crustaceans ranged from 1.36 mg/l for adult pink shrimp to 1.56 mg/l for 10-day-old mysids. Similarly, estimated LC50 values for fish ranged from 1.34 mg/l in one of the three tests with pinfish to 2.22 mg/l in one of the two tests with scaled sardines. The majority of mortality attributable to low DO concentrations in our experiments usually occurred within the first 4 h of exposure. LC50 values for the species tested are below the WQC recommended protective limit of 2.3 mg/l for juvenile and adult animals.     

Levels and distribution of trace metals in surface sediments from Kongsfjorden, Svalbard, Norwegian Arctic

Trace metal contents (Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn) have been measured in 27 surface sediment samples collected from Kongsfjorden, Svalbard, Norwegian Arctic. The analyses yielded concentration values (in mg kg^?1) of 0.13–0.63 for Cd, 11.89–21.90 for Co, 48.65–81.84 for Cr, 21.26–36.60 for Cu, 299.59–683.48 for Mn, 22.43–35.39 for Ni, 10.68–36.59 for Pb, 50.28–199.07 for Zn and 8.09–65.34 for Hg (in ng g^?1), respectively. Relative cumulative frequency method has been used to define the baseline values of these metals, which (in mg kg^?1) were 0.14 for Cd, 13.56 for Co, 57.86 for Cr, 25.14 for Cu, 364.08 for Mn, 26.22 for Ni, 17.46 for Pb, 70.49 for Zn and 9.76 for Hg (in ng g^?1), respectively. The enrichment factor analysis indicated that Hg showed some extent of anthropogenic pollution, while Pb, Zn and Cd showed limited anthropogenic contamination in the study areas.     

Energetics of Euphausia pacifica. I. Effects of body carbon and nitrogen and temperature on measured and predicted production

Laboratory production during the life span of Euphausia pacifica was measured directly (as the sum of growth, molting and reproduction) and indirectly (as assimilation minus metabolism and leakage) to test the hypothesis that weight-specific production is a constant for all sizes. Euphausiids were collected in Puget Sound, Washington State, USA, from September 1973 to March 1978. Equations were determined (in terms of carbon and nitrogen at 8° and 12° C) expressing the relationships between body weight and the daily rates of growth, molting, reproduction, ingestion and metabolism. The allometric equation (R=aW ^b ) best related body weight (W) to the rate (R) for growth, molting, ingestion, respiration and excretion for life stages from late larvae through adults. As predicted by the original above hypothesis, the weight-specific coefficient (b) was close to 1.0 for ingestion and excretion; in contrast, b was 0.62 for growth, and 0.77 to 0.85 for molting and respiration. The Q₁₀ s also varied: 3.5 for growth, 2.4 for molting, about 3.0 for ingestion, and 2.0 for respiration and excretion. Assimilation efficiencies, for all weights and at both temperatures, were 81.3% of carbon and 85.9% of nitrogen ingested. The relationships between rate and body weight of early larvae for growth and molting were linear, as was the relationship for reproduction in adults. Weight-specific production was higher by I to 2% at 12° than 8° C for all life stages, and was 2 to 4% for carbon and 2 to 6% for nitrogen in adults, but 13 to 17% for carbon and 14 to 15% for nitrogen in early furcilia larvae. The null hypothesis was rejected for production measured directly, but would have been accepted if only an indirect measurement of nitrogen production had been considered. Clearly, indirect measurement incorporates all errors of measurement and assumption and makes interpretation difficult.     

海洋放射性污染生态风险评价研究进展

近年来,随着我国核电事业迅猛发展,海洋放射性污染的风险激增,放射物质的事故性污染将成为海洋环境一个重要问题。目前,海洋环境放射性污染风险评估的研究仍然较为薄弱,开展海洋放射性污染生态风险评价有助于了解事故对海洋生态的危害程度,为海洋与海岸带环境管理提供科学决策依据,维护海洋生态系统的健康与安全。梳理总结当前国内外海洋放射性污染生态风险评价的相关研究进展,结果表明:目前国内外对海洋放射性污染生态风险评价尚未做出科学的定义;现有海洋放射性污染生态风险评价的技术路线大体可归纳为基于经典风险评估框架和基于迭代的生态风险评价框架2种类型;ERICA Tool模型以及RESRAD-BIOTA模型是目前放射性风险评价中应用最多的方法 ,但存在海洋放射性污染标准限值少的问题;现有的研究主要集中于评估事故中后期均衡条件下的长期慢性暴露评价,对事故初期的高剂量、短期急性暴露的风险影响研究较少;我国海洋放射性污染的生态风险评价与环境影响评价的概念混淆,至今没有明确的海洋放射性污染生态风险评价的概念及技术框架。     

Pharmazeutische Wirkstoffe und Umweltschutz

On 26 April this year the German Environmental Advisory Council (SRU) published a statement on ‘Pharmaceuticals in the environment’ and pointed considerable need for action to understand and to reduce the risks from diffuse pharmaceutical inputs in the environment. On the one hand, it is urgently necessary to improve the database for environmental risk assessments; on the other hand measures should already be taken to minimize harmful inputs. Fortunately, the new regulations for an application for an authorization to market new pharmaceuticals require an environmental risk assessment. However, there is a lack of information on possible impacts from long time admitted medicines which may be responsible for harmful active substances detectable in the environment. To remove this data deficit, a European programme for risk evaluation of old pharmaceuticals should be established. It is necessary for an adequate risk assessment to look at all impacts of one active substance or all substances same-directed in their active potential summativ and to generate regularly consumption data in particular for the use of veterinary products. The hot spots of contamination are the introduction of large scale volumes of active pharmaceutical ingredients for human use like diclofenac and carbamazepin as well as hormones into surface waters, as well as the application of antibiotics-loaded economic fertilizers on soils. Not to be neglected is the application of antiparasitics in animals kept on pasture. With the assessment of the use of pharmaceuticals for all purposes special attention is needed on antibiotic resistance. For the mitigation of environmental exposures there are exposures measures necessary to reduce use of antibiotics in farming, for the application of new effective technologies in treatment sewage — as for example ozonation, filtration with activated carbon or membrane filtration — as well as for the labelling of environmentally harmful medicinal products.     

Trace metal contents in some brands of canned beef in Nigeria

The concentrations of cadmium, chromium, copper, lead, zinc, manganese, iron, cobalt, and nickel in some brands of canned beef in Nigerian markets were determined by atomic absorption spectrophotometry. The mean concentration ranges for these metals in mg?kg^?1 were 0.02–0.37 for Cd, <0.04–0.75 for Cr, 1.1–2.4 for Cu, <0.001–1.5 for Pb, 1.1–8.0 for Zn, <0.04–0.57 for Mn, 13.8–28.8 for Fe, 0.05–0.26 for Co, and 0.8–5.9 for Ni. The estimated dietary intake of metals from these products did not indicate any risk since the values were far below the permissible dietary intakes.     

Qualitative and quantitative assessment of the risk from the exposure to fetotoxic chemical compounds

A new mathematical dose-response model for the expected probability of toxic response and also for the expected measure of the overdispersion parameter for the reproductive and developmental risk assessment is proposed. The model for the expected probability of toxic response is an improvised Weibull dose-response model incorporating the litter-size effect while the model for the overdispersion parameter is a polynomial function of the dose level. A beta-binomial distribution for the number of offspring showing toxic responses in a litter satisfactorily accounts for the extra-binomial variation and the intralitter correlation of responses of these pups. Confidence limits for low-dose extrapolation are based on the asymptotic distribution of the likelihood ratio. The safe dose for human exposure is then calculated by simple linear extrapolation. The model for overdispersion allows us to obtain the estimates of the overdispersion parameter at these dosages. This was not possible in the earlier models. The proposed model is illustrated by an application to a study on the effect of exposure to diethylhexylphthalate in mice. The results are compared with those obtained by Chen and Kodell (1989) who have applied the simple Weibull dose-response model to the same data set.This paper was prepared with partial support from the United States Environmental Protection Agency under a Cooperative Agreement Number CR-815273. The contents have not been subject to Agency review and therefore do not necessarily reflect the views or policies of the Agency and no official endorsement should be inferred.     

城市垃圾二次性好氧堆肥化工艺的若干设计方程

二次性好氧堆肥化工艺是基于将堆肥化过程中高温微生物和中温微生物在分开的、各自适宜的环境中 进行不同基质降解和稳定化的一种较新工艺．通过实验，由物料平衡式结合微生物反应动力学 建立了 城市垃圾二次性好氧堆肥工艺的若干基本设计方程式：一次发酵阶段的生物降解方程， Ｋ Ａｖ 值高的易降解物具有一级反应的性质，试验求出的比率常数 Ｋｄ 为０１１９ ｄ － １ ；一次 发酵阶段的堆肥减量二元线性方程，减量主要与挥发性固体降解率和水份蒸发量有关；一次 发酵动态反应器容积和二次发酵构筑物有效面积的计算式，计算式主要考虑了减量、容重变化及堆肥返料量的影响；一次发酵阶段所需理论通风量的计算式，通风量主要由微生 物需氧量和水份蒸发量所需的空气量组成，后者需气量往往大于前者，有时高达２ ～６ 倍．     

The implications of model complexity for environmental management

The purpose of this paper is to consider the implicatons of model complexity for the quality of the information provided by models of production activities that account for the processes involved in residuals generation and treatment. Using each of the three primary technologies for iron and steel-making industry and models of varying detail for each, the paper compares the estimated levels of residuals generated and treatment costs for both atmospheric and waterborne effluents. The findings suggest that there are strategic details in model construction which have fundamental implications for the design of environmental policies. Moreover, preliminary estimates of the costs of model construction and operation suggest that policymakers may not be able to afford complexity for its own sake. Rather these costs will require the development of methods to isolate the strategic details in each technology that are potentially important to environmental policies.     

Landscape-level thresholds, and newt conservation.

Ecological thresholds are defined as points or zones at which a rapid change occurs from one ecological condition to another. The existence of thresholds in species-habitat relationships has important implications for management, but the lack of concordance across studies and the wide range of methods used make generalizations difficult. We used two different statistical methods to test for the existence of thresholds for both individual species and the whole community, using three newt species as models. Based on a sample of 371 ponds, we found significant thresholds for both landscape configuration and composition. These were for the relationships between distance to forest and occurrence of Triturus alpestris and T. helveticus, and forest and crop cover and T. helveticus. Variability in the location of thresholds observed for the different species in this study caution against their use at the community level. Future studies should be based on the identification and assessment of thresholds for targeted species. Thresholds can be a useful concept from which tools may be developed to focus conservation effort for threatened species and their habitats.     

Effectiveness of amphibians as biodiversity surrogates in pond conservation

Amphibian decline has led to worldwide conservation efforts, including the identification and designation of sites for their protection. These sites could also play an important role in the conservation of other freshwater taxa. In 89 ponds in Switzerland, we assessed the effectiveness of amphibians as a surrogate for 4 taxonomic groups that occur in the same freshwater ecosystems as amphibians: dragonflies, aquatic beetles, aquatic gastropods, and aquatic plants. The ponds were all of high value for amphibian conservation. Cross‐taxon correlations were tested for species richness and conservation value, and Mantel tests were used to investigate community congruence. Species richness, conservation value, and community composition of amphibians were weakly congruent with these measures for the other taxonomic groups. Paired comparisons for the 5 groups considered showed that for each metric, amphibians had the lowest degree of congruence. Our results imply that site designation for amphibian conservation will not necessarily provide protection for freshwater biodiversity as a whole. To provide adequate protection for freshwater species, we recommend other taxonomic groups be considered in addition to amphibians in the prioritization and site designation process.     

Metrics of progress in the understanding and management of threats to Australian birds

Although evidence-based approaches have become commonplace for determining the success of conservation measures for the management of threatened taxa, there are no standard metrics for assessing progress in research or management. We developed 5 metrics to meet this need for threatened taxa and to quantify the need for further action and effective alleviation of threats. These metrics (research need, research achievement, management need, management achievement, and percent threat reduction) can be aggregated to examine trends for an individual taxon or for threats across multiple taxa. We tested the utility of these metrics by applying them to Australian threatened birds, which appears to be the first time that progress in research and management of threats has been assessed for all threatened taxa in a faunal group at a continental scale. Some research has been conducted on nearly three-quarters of known threats to taxa, and there is a clear understanding of how to alleviate nearly half of the threats with the highest impact. Some management has been attempted on nearly half the threats. Management outcomes ranged from successful trials to complete mitigation of the threat, including for one-third of high-impact threats. Progress in both research and management tended to be greater for taxa that were monitored or occurred on oceanic islands. Predation by cats had the highest potential threat score. However, there has been some success reducing the impact of cat predation, so climate change (particularly drought), now poses the greatest threat to Australian threatened birds. Our results demonstrate the potential for the proposed metrics to encapsulate the major trends in research and management of both threats and threatened taxa and provide a basis for international comparisons of evidence-based conservation science.     

Income inequality and willingness to pay for environmental public goods

We study how the distribution of income among members of society, and income inequality in particular, affects social willingness to pay (WTP) for environmental public goods. We find that social WTP for environmental goods decreases (increases) with income inequality if and only if environmental goods and manufactured goods are substitutes (complements). We derive adjustment factors for benefit transfer to control for differences in income distributions between a study site and a policy site. For illustration, we quantify how social WTP for environmental public goods depends on the respective income distributions for empirical case studies in Sweden and the World at large. We find that the adjustment for income inequality can be substantial.