多种聚氧乙烯牛脂胺混合物MON 0818的水生环境危害评估：实验室急性暴露实验基础上的物种敏感度分布

本实验利用标准短期(48- 96 h)实验室测试测定了包括初级生产者，底栖无脊椎动物，水蚤类动物，软体动物和鱼类在内的15种水生生物对于MON 0818的敏感性。MON 0818是一种商业表面活性剂，由多种聚氧乙烯牛脂胺混合而成。此外本实验使用模糊网纹蚤(Ceriodaphnia dubia)潜在的长期(8 d)毒性，确定了暴露浓度。长期毒性测试中未在任何终端指标中发现显著效果。利用得出的数据和文献记载得到物种敏感度在4种暴露条件下的分布，通过对比物种敏感度分布进行了tier-1危害评估。评估显示在本研究规划下(以综述为原型，研究林业除草剂；12 L标准每公顷，等于4.27 kg每公顷) 最差的情况(无意中以最大标签使用速率直接过量喷洒到15 cm深的水体中)会造成中等危害(43.1%的物种处于暴露中，高于中位有效浓度水平)。在更多以最大使用速率使用的典型情况下，受到损害的物种降至20.9%(6 L标准每公顷，相当于2.14 kg每公顷)，在更频繁的雇佣施用速率(2.5 L标准每公顷，相当于0.89 kg每公顷)下，受损物种比例降至6.9%。通过草甘膦在环境中的最大测定浓度计算得到MON 0818的浓度，最终受损物种比例(3.8%)则小于此浓度下受损物种比例(5%)。
精选自Jose L. Rodriguez-Gil, Ryan Prosser, David Poirier, Linda Lissemore, Dean Thompson, Mark Hanson, Keith R. Solomon. Aquatic hazard assessment of MON 0818, a commercial mixture of alkylamine ethoxylates commonly used in glyphosate-containing herbicide formulations. Part 1: Species sensitivity distribution from laboratory acute exposures. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 501–511, July 2017. DOI: 10.1002/etc.3559
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3559/full
     

Frugal cannibals: how consuming conspecific tissues can provide conditional benefits to wood frog tadpoles (Lithobates sylvaticus)

Tadpoles show considerable behavioral plasticity. When population densities become high, tadpoles often become cannibalistic, likely in response to intense competition. Conspecific tissues are potentially an ideal diet by composition and should greatly improve growth and development. However, the potential release of alarm cues from the tissues of injured conspecifics may act to deter potential cannibals from feeding. We conducted multiple feeding experiments to test the relative effects that a diet of conspecifics has on tadpole growth and development. Results indicate that while conspecific tissues represent a better alternative to starvation and provide some benefits over low-protein diets, such a diet can have detrimental effects to tadpole growth and/or development relative to diets of similar protein content. Additionally, tadpoles raised individually appear to avoid consuming conspecific tissues and may continue to do so until they suffer from the effects of starvation. However, tadpoles readily fed upon conspecific tissues immediately when raised with competitors. These results suggest that cannibalism may occur as a result of competition rather than the specific quality of available diets, unless such diets lead to starvation.     

Criteria to determine likelihood of brain injury during explosive events

The occurrence of blast-induced brain injury in individuals serving in Iraq and Afghanistan is dramatically higher than in past conflicts. This has been attributed in part to the prevalence of roadside improvised explosive devices, or IEDs. There is a call from the military medical community to reduce the reliance on victim self-reporting as the primary diagnosis technique to determine the likelihood of brain injury after a blast. This study demonstrates the ability to establish criteria which correlates easily measured parameters to the probability of cerebral contusion and, thus, brain injury. Computational fluid dynamics (CFD) is used to establish the environment from a full range of threats. This is combined with bond graph modeling of varying levels of fidelity to estimate the dynamics of the skull and brain. Results clearly show that a boundary exists in the threat parameter space that determines whether brain injury is probable.     

Limitations on the role of incorporated organic matter in reducing pesticide leaching.

The use of organic amendments has been suggested as a method of controlling pesticide leaching through soils. The enarenados soils of the intensive horticulture of the Almeria province of southern Spain contain buried organic matter horizons above a soil layer amended with clay. This region is ideal for understanding the potential for and limitations of organic amendments in preventing pesticide pollution. This study measured the sorption and degradation potential of carbofuran in this soil system and the hydrological behaviour of the soil horizons. The sorption of carbofuran was controlled by the organic carbon content, the degradation was strongly pH-dependent and the acidic organic layer protected the sorbed carbofuran against degradation. Hydrologically, the soil system is dominated by ponding above an amended clay layer and by the presence of macropores that can transport water through this clay. A simple model is proposed on this basis and shows that although high levels of dissolved organic carbon can be released by buried organic horizons, the major control on re-release of sorbed pesticide is the potential for sorption hysteresis in this organic layer. A comparison of sorption and degradation data for carbamate insecticides used in the region with groundwater observations for these compounds shows that no amount of incorporated organic would protect against pollution from highly water-soluble compounds.     

Environmental Indicators of Biofuel Sustainability: What About Context?

Indicators of the environmental sustainability of biofuel production, distribution, and use should be selected, measured, and interpreted with respect to the context in which they are used. The context of a sustainability assessment includes the purpose, the particular biofuel production and distribution system, policy conditions, stakeholder values, location, temporal influences, spatial scale, baselines, and reference scenarios. We recommend that biofuel sustainability questions be formulated with respect to the context, that appropriate indicators of environmental sustainability be developed or selected from more generic suites, and that decision makers consider context in ascribing meaning to indicators. In addition, considerations such as technical objectives, varying values and perspectives of stakeholder groups, indicator cost, and availability and reliability of data need to be understood and considered. Sustainability indicators for biofuels are most useful if adequate historical data are available, information can be collected at appropriate spatial and temporal scales, organizations are committed to use indicator information in the decision-making process, and indicators can effectively guide behavior toward more sustainable practices.     

An exposure assessment for selected pharmaceuticals within a watershed in Southern Ontario

Recent studies from a number of countries have shown that measurable concentrations of both human and veterinary pharmaceuticals can be found in a variety of environmental matrices such as surface and ground water, soils, and sediments. Few data are available that characterize the sources, exposure and effects of pharmaceuticals in the environment and there is clearly a need to define these parameters within a Canadian context. We present in this paper the first report in southern Ontario, Canada on the geographic and temporal distribution of pharmaceuticals detected within seven tributaries receiving primarily agricultural inputs in a typical watershed. Of the 28 pharmaceuticals surveyed, 14 were detected in the streams sampled (n=125). Temporal trends in concentration for five frequently detected pharmaceuticals show pulses occurring between May and November of 2003 at similar but varying times over the seasons, depending on the pharmaceuticals, flow rate, and precipitation. Fluctuations in concentration of ions indicative of agricultural run off, such as nitrate and phosphate, were not found to be useful predictors of changes in pharmaceutical concentration (P>0.4), however a significant correlation between dissolved organic carbon and monensin and carbamazepine concentrations were observed (P<0.013). Exposure profiles illustrating concentration distributions for three of the more prevalent pharmaceuticals detected, including lincomycin, monensin and carbamazepine, showed a log normal distribution, useful for calculating centiles of environmental concentrations. While distributions of estimated total potency of pharmaceuticals detected in the surface waters suggested small risks of environmental effects of mixtures to daphnia, green algae, Lemna gibba, and fish, the significance of non-target effects and impacts due to chronic low level exposures to chemical mixtures remains unclear.     

Predictive mapping of soil organic carbon in wet cultivated lands using classification-tree based models: The case study of Denmark

Soil organic carbon (SOC) is one of the most important carbon stocks globally and has large potential to affect global climate. Distribution patterns of SOC in Denmark constitute a nation-wide baseline for studies on soil carbon changes (with respect to Kyoto protocol). This paper predicts and maps the geographic distribution of SOC across Denmark using remote sensing (RS), geographic information systems (GISs) and decision-tree modeling (un-pruned and pruned classification trees). Seventeen parameters, i.e. parent material, soil type, landscape type, elevation, slope gradient, slope aspect, mean curvature, plan curvature, profile curvature, flow accumulation, specific catchment area, tangent slope, tangent curvature, steady-state wetness index, Normalized Difference Vegetation Index (NDVI), Normalized Difference Wetness Index (NDWI) and Soil Color Index (SCI) were generated to statistically explain SOC field measurements in the area of interest (Denmark). A large number of tree-based classification models (588) were developed using (i) all of the parameters, (ii) all Digital Elevation Model (DEM) parameters only, (iii) the primary DEM parameters only, (iv), the remote sensing (RS) indices only, (v) selected pairs of parameters, (vi) soil type, parent material and landscape type only, and (vii) the parameters having a high impact on SOC distribution in built pruned trees. The best constructed classification tree models (in the number of three) with the lowest misclassification error (ME) and the lowest number of nodes (N) as well are: (i) the tree (T1) combining all of the parameters (ME = 29.5%; N = 54); (ii) the tree (T2) based on the parent material, soil type and landscape type (ME = 31.5%; N = 14); and (iii) the tree (T3) constructed using parent material, soil type, landscape type, elevation, tangent slope and SCI (ME = 30%; N = 39). The produced SOC maps at 1:50,000 cartographic scale using these trees are highly matching with coincidence values equal to 90.5% (Map T1/Map T2), 95% (Map T1/Map T3) and 91% (Map T2/Map T3). The overall accuracies of these maps once compared with field observations were estimated to be 69.54% (Map T1), 68.87% (Map T2) and 69.41% (Map T3). The proposed tree models are relatively simple, and may be also applied to other areas.     

Brownfields Update: The Reform of the Brownfields Economic Redevelopment Initiative

This journal first reported on the U.S. EPA's Brownfields Initiative in the summer 1995 edition of Remediation. At that time, the initiative was only about 15 months old, most of the state programs were in proposal stages, and little federal legislation addressing brownfields had been proposed. Today, brownfields has become such a common term that almost every environmental professional is familiar with it. The EPA has placed extremely high priority on the Brownfields Initiative and it has become a politically hot issue. This article provides an update on the current status of EPA's Brownfields program and also discusses recent legislation proposed by Congress to promote brownfields redevelopment. © 2001 John Wiley & Sons, Inc.