The CPCAT as a novel tool to overcome the shortcomings of NOEC/LOEC statistics in ecotoxicology: a simulation study to evaluate the statistical power

Species reproduction is an important determinant of population dynamics. As such, this is an important parameter in environmental risk assessment. The closure principle computational approach test (CPCAT) was recently proposed as a method to derive a NOEC/LOEC for reproduction count data such as the number of juvenile Daphnia. The Poisson distribution used by CPCAT can be too restrictive as a model of the data-generating process. In practice, the generalized Poisson distribution could be more appropriate, as it allows for inequality of the population mean \(\mu\) and the population variance \(\sigma ^2\). It is of fundamental interest to explore the statistical power of CPCAT and the probability of determining a regulatory relevant effect correctly. Using a simulation, we varied between Poisson distribution (\(\mu =\sigma ^2\)) and generalized Poisson distribution allowing for over-dispersion (\(\mu <\sigma ^2\)) and under-dispersion (\(\mu >\sigma ^2\)). The results indicated that the probability of detecting the LOEC/NOEC correctly was \(\ge 0.8\) provided the effect was at least 20% above or below the mean level of the control group and mean reproduction of the control was at least 50 individuals while over-dispersion was missing. Specifically, under-dispersion increased, whereas over-dispersion reduced the statistical power of the CPCAT. Using the well-known Hampel identifier, we propose a simple and straight forward method to assess whether the data-generating process of real data could be over- or under-dispersed.     

德国公司环境报告评估

1994年进行了德国公司环境报告的第一次排名.1995年和1998年又进行了两次排名,以确定环境报告和陈述的数目已增加的程度,及其质量是否有所改善.基于所使用的基准,已经显示公司报告的质量有颇大差异.虽然总体质量有了改善,但大多数报告都有许多重要不足.     

Development of a new hydrocarbon index for oil-in-water

A new robust method for determination of hydrocarbons in water without use of Freon^™ or other halogenated solvents has been validated and subjected to an interlaboratory exercise. The method is based on extraction with a light hydrocarbon (boiling point in the 39–69°C range), followed by cleanup for removal of polar components and detection by gas chromatography (GC) with flame ionisation (FID) detection. The performance characteristics of the method are comparable with that of the previous Freon-IR method with recoveries in the 60–80% range and reproducibility (between laboratory variations) of about 30%.

A screening method for hydrocarbons in the range 5 ppm and above based on infrared spectroscopy (IR), and a promising method for detection of low levels based on solid phase extraction (SPE) has been tested and validated.     

Degrader density determines spatial variability of 2,6-dichlorobenzamide mineralisation in soil

The metabolite 2,6-dichlorobenzamide (BAM) is a frequent groundwater pollutant produced during degradation of the herbicide 2,6-dichlorobenzonitrile (dichlobenile). Spatial variability of BAM mineralisation is uncharacterized in surface soil, however, and factors controlling the heterogeneity remain unknown. We addressed these issues by sample-to-sample comparisons of BAM mineralisation rates and a range of soil characteristics at spatial scales ranging from meters to centimetres. For mineralisation assays nano-molar concentrations of labelled BAM were added to determine mineralisation rates under realistic conditions. We found a significant variability of BAM mineralisation which increased with decreasing spatial scale. BAM mineralisation rates were correlated to the density of BAM-degrading bacteria but not to water content, TOC, NH₄⁺, NO₃⁻, or pH. The genus Aminobacter, which contains the only BAM degraders known, was detected in MPN samples of BAM degraders by a specific PCR assay targeting the 16S rRNA gene, confirming a role of Aminobacter in BAM mineralisation.     

Pb isotopes as tracers of mining-related Pb in lichens, seaweed and mussels near a former Pb-Zn mine in West Greenland

Identification of mining-related contaminants is important in order to assess the spreading of contaminants from mining as well as for site remediation purposes. This study focuses on lead (Pb) contamination in biota near the abandoned ‘Black Angel Mine’ in West Greenland in the period 1988-2008. Stable Pb isotope ratios and total Pb concentrations were determined in lichens, seaweed and mussels as well as in marine sediments. The results show that natural background Pb (²⁰⁷Pb/²⁰⁶Pb: 0.704-0.767) and Pb originating from the mine ore (²⁰⁷Pb/²⁰⁶Pb: 0.955) have distinct isotopic fingerprints. Total Pb in lichens, seaweed, and mussels was measured at values up to 633, 19 and 1536 mg kg⁻¹ dry weight, respectively, and is shown to be a mixture of natural Pb and ore-Pb. This enables quantification of mining-related Pb and shows that application of Pb isotope data is a valuable tool for monitoring mining pollution.     

Transport impacts on atmosphere and climate: Land transport

Emissions from land transport, and from road transport in particular, have significant impacts on the atmosphere and on climate change. This assessment gives an overview of past, present and future emissions from land transport, of their impacts on the atmospheric composition and air quality, on human health and climate change and on options for mitigation.In the past vehicle exhaust emission control has successfully reduced emissions of nitrogen oxides, carbon monoxide, volatile organic compounds and particulate matter. This contributed to improved air quality and reduced health impacts in industrialised countries. In developing countries however, pollutant emissions have been growing strongly, adversely affecting many populations. In addition, ozone and particulate matter change the radiative balance and hence contribute to global warming on shorter time scales. Latest knowledge on the magnitude of land transport's impact on global warming is reviewed here.In the future, road transport's emissions of these pollutants are expected to stagnate and then decrease globally. This will then help to improve the air quality notably in developing countries. On the contrary, emissions of carbon dioxide and of halocarbons from mobile air conditioners have been globally increasing and are further expected to grow. Consequently, road transport's impact on climate is gaining in importance. The expected efficiency improvements of vehicles and the introduction of biofuels will not be sufficient to offset the expected strong growth in both, passenger and freight transportation. Technical measures could offer a significant reduction potential, but strong interventions would be needed as markets do not initiate the necessary changes. Further reductions would need a resolute expansion of low-carbon fuels, a tripling of vehicle fuel efficiency and a stagnation in absolute transport volumes. Land transport will remain a key sector in climate change mitigation during the next decades.     

Does the Coase theorem hold in real markets? An application to the negotiations between waterworks and farmers in Denmark

The Coase theorem depends on a number of assumptions, among others, perfect information about each other's payoff function, maximising behaviour and zero transaction costs. An important question is whether the Coase theorem holds for real market transactions when these assumptions are violated. This is the question examined in this paper. We consider the results of Danish waterworks' attempts to establish voluntary cultivation agreements with Danish farmers. A survey of these negotiations shows that the Coase theorem is not robust in the presence of imperfect information, non-maximising behaviour and transaction costs. Thus, negotiations between Danish waterworks and farmers may not be a suitable mechanism to achieve efficiency in the protection of groundwater quality due to violations of the assumptions of the Coase theorem. The use of standard schemes or government intervention (e.g. expropriation) may, under some conditions, be a more effective and cost efficient approach for the protection of vulnerable groundwater resources in Denmark.     

Farmers’ Attitude Towards Animal Welfare Aspects and Their Practice in Organic Dairy Calf Rearing: a Case Study in Selected Nordic Farms

In organic philosophy, the concept of “naturalness” is of major importance. According to the organic interpretation of animal welfare, natural living is considered a precondition for accomplishing welfare and the principal aims of organic production include the provision of natural living conditions for animals. However, respective regulations are lacking in organic legislation. In practice, the life of a calf in organic rearing systems can deviate from being natural, since common practices in dairy farms include early weaning, dehorning, or cow-calf separation soon after birth. This case study explores how calf welfare is approached in six different organic dairy farms and how far the concept of naturalness is implemented. The farms included in this study were located in Norway and Sweden. A semi-structured questionnaire was used for data collection. The interviewed farmers approach the concept of welfare in various ways and state that “naturalness” is an aspect of animal welfare. However, in practice in the calf rearing systems under study, only a few “naturalness” aspects were implemented. Reasons for the observed discrepancy might lie in differing understandings of “naturalness,” in economic restrictions, and in other trade-offs resulting from production system inherent characteristics and in limited regulation concerning provision of natural living aspects.     

Quantification of centimeter-scale spatial variation in PAH, glucose and benzoic acid mineralization and soil organic matter in road-side soil

The aim of the study was to determine centimeter-scale spatial variation in mineralization potential in diffusely polluted soil. To this end we employed a 96-well microplate method to measure the mineralization of ¹⁴C-labeled organic compounds in deep-well microplates and thereby compile mineralization curves for 348 soil samples of 0.2-cm³. Centimeter-scale spatial variation in organic matter and the mineralization of glucose, benzoic acid, and PAHs (phenanthrene and pyrene) was determined for urban road-side soil sampled as arrays (7 × 11 cm) of 96 subsamples. The spatial variation in mineralization was visualized by means of 2-D contour maps and quantified by means of semivariograms. The geostatistical analysis showed that the easily degradable compounds (glucose and benzoic acid) exhibited little spatial variation in mineralization potential, whereas the mineralization was highly heterogeneous for the PAH compounds that require specialized degraders. The spatial heterogeneity should be taken into account when estimating natural attenuation rates.