Framework for the environmental impact assessment of operational shipping

Shipping is an important source of pollution affecting both atmospheric and aquatic environments. To allow for efficient mitigation of environmental degradation, it is essential to know the extent of the impacts of shipping in relation to other sources of pollution. Here, we give a perspective on a holistic approach to studies of the environmental impacts of operational shipping through presentation of an assessment framework developed and applied on a case of shipping in the Baltic Sea. Through transfer of knowledge and concepts, previously used in assessments of air pollution, now applied to assessments of marine pollution and underwater noise, the horizon of understanding of shipping-related impacts is significantly improved. It identifies the main areas of environmental degradation caused by shipping and potential improvements through legislation and technological development. However, as the vast majority of contaminants discharged into the sea are not routinely monitored and assessed, the links between pressure of contaminants from shipping and environmental state and impacts will not be caught in the current environmental regulatory frameworks.     

How do different process options and evaluation settings affect economic and environmental assessments? A case study on methyl methacrylate (MMA) production processes

We present an investigation on how economic and environmental assessment results change when different process options or evaluation settings are considered. As the main case study the production technology of methyl methacrylate (MMA) is investigated. Six commercial processes using different reaction routes are modelled and evaluated with respect to their economic and environmental performance. On these six base case models different process options and evaluation settings are considered and the resulting impacts on the assessment results are quantified. Major findings of the study are that the more decision-variables become fixed, the smaller becomes the impact of the decisions still to be taken—but not only with respect to the economic performance but also with regard to the environmental assessment result. Along the process development steps the potential impacts on the economic and environmental performance decrease to the same degree. The results obtained for the evaluation settings do not show such a systematic pattern as those for the process options. This finding indicates that decision makers face many options in the economic and especially the environmental assessment of chemical processes which might lead to quite different magnitudes in variability due to either the choice of method or the choice of method parameters. This paper demonstrates that the resulting variability might be crucial with respect to the decision making outcome.     

Synopsis of the temporal variation of particulate matter composition and size

A synopsis of the detailed temporal variation of the size and number distribution of particulate matter (PM) and its chemical composition on the basis of measurements performed by several regional research consortia funded by the U.S. Environmental Protection Agency (EPA) PM Supersite Program is presented. This program deployed and evaluated a variety of research and emerging commercial measurement technologies to investigate the physical and chemical properties of atmospheric aerosols at a level of detail never before achieved. Most notably these studies demonstrated that systematic size-segregated measurements of mass, number, and associated chemical composition of the fine (PM2.5) and ultrafine (PM0.1) fraction of ambient aerosol with a time resolution down to minutes and less is achievable. A wealth of new information on the temporal variation of aerosol has been added to the existing knowledge pool that can be mined to resolve outstanding research and policy-related questions. This paper explores the nature of temporal variations (on time scales from several minutes to hours) in the chemical and physical properties of PM and its implications in the identification of PM formation processes, and source attribution (primary versus secondary), the contribution of local versus transported PM and the development of effective PM control strategies. The PM Supersite results summarized indicate that location, time of day, and season significantly influence not only the mass and chemical composition but also the size-resolved chemical/elemental composition of PM. Ambient measurements also show that ultrafine particles have different compositions and make up only a small portion of the PM mass concentration compared with inhalable coarse and fine particles, but their number concentration is significantly larger than their coarse or fine counterparts. PM size classes show differences in the relative amounts of nitrates, sulfates, crustal materials, and most especially carbon as well as variations in seasonal and diurnal patterns.     

Speciation and toxicological relevance of manganese in humans

Although manganese is an essential trace element, concerns are rising about the Mn exposure of humans being related to neurotoxic effects. This review summarizes several aspects of this topic to provide updated information on Mn related investigations, including chemical speciation of Mn-compounds. The paper starts with some chemical aspects of Mn and its compounds, enlightening oxidation states in general and in biological matrices. This is followed by considerations on natural sources of human exposure, on occupational sources and on anthropogenically caused environmental sources, for example from the use of methylcyclopentadienyl manganese tricarbonyl (MMT). Next, the paper deals with Mn levels in the human organism, showing normal Mn concentrations in various tissues or body fluids, and continues with the toxicology of Mn, i.e. absorption, distribution and excretion. Of specific concern is the transfer of Mn to the brain which is the relevant neurotoxic target. In this context, parallels and differences between primary and Mn-dependent Parkinsonism are discussed, concluding with a risk assessment and a consideration of susceptible groups. The main part of this review focuses on recent investigations on Mn speciation. Analytical problems and their solutions are also described for correct identification of relevant Mn-compounds in matrices of human origin. Finally, future needs are discussed, such as further investigations on those Mn-species which may overcome neural barrier control, on disease-modulated barrier control, on susceptibility to certain Mn-species, and on the interaction of Mn with Fe-homeostasis in the brain.     

Characterization of slow pyrolysis biochars: effects of feedstocks and pyrolysis temperature on biochar properties

Biochars are increasingly used as soil amendment and for C sequestration in soils. The influence of feedstock differences and pyrolysis temperature on biochar characteristics has been widely studied. However, there is a lack of knowledge about the formation of potentially toxic compounds that remain in the biochars after pyrolysis. We investigated biochars from three feedstocks (wheat straw, poplar wood, and spruce wood) that were slowly pyrolyzed at 400, 460, and 525°C for 5 h (straw) and 10 h (woodchips), respectively. We characterized the biochars' pH, electrical conductivity, elemental composition (by dry combustion and X-ray fluorescence), surface area (by N adsorption), water-extractable major elements, and cation exchange capacity (CEC). We further conducted differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffractometry to obtain information on the biochars' molecular characteristics and mineralogical composition. We investigated trace metal content, total polycyclic aromatic hydrocarbon (PAH) content, and PAH composition in the biochars. The highest salt (4.92 mS cm) and ash (12.7%) contents were found in straw-derived biochars. The H/C ratios of biochars with highest treatment temperature (HTT) 525°C were 0.46 to 0.40. Surface areas were low but increased (1.8-56 m g) with increasing HTT, whereas CEC decreased (162-52 mmol kg) with increasing HTT. The results of DSC and FTIR suggested a loss of labile, aliphatic compounds during pyrolysis and the formation of more recalcitrant, aromatic constituents. X-ray diffractometry patterns indicated a mineralogical restructuring of biochars with increasing HTT. Water-extractable major and trace elements varied considerably with feedstock composition, with trace elements also affected by HTT. Total PAH contents (sum of EPA 16 PAHs) were highly variable with values up to 33.7 mg kg; irrespective of feedstock type, the composition of PAHs showed increasing dominance of naphthalene with increasing HTT. The results demonstrate that biochars are highly heterogeneous materials that, depending on feedstock and HTT, may be suitable for soil application by contributing to the nutrient status and adding recalcitrant C to the soil but also potentially pose ecotoxicological challenges.     

华北平原冬小麦-夏玉米轮作体系氮肥的氨挥发

 利用可多点原位测定氨挥发的风洞系统,监测了华北平原2002～2004年冬小麦-夏玉米轮作体系传统和优化氮肥管理下的氨挥发损失.结果表明,氨挥发主要发生在施肥后2～3周内,以施肥后连续采样15d的氨挥发累积量作为总排放量,相同施氮量下生长季夏玉米的氨挥发大于冬小麦.优化处理的氨挥发平均损失率(35.9%)显著高于传统处理(20.9%),但从氨挥发绝对量上看,传统处理为125.1kgN/hm²,优化处理为42.3kgN/hm²,降幅达66.2%.施肥和灌水方式显著影响氨挥发,撒施碳铵后翻耕的氨挥发损失为10.1%,追肥撒施的氨挥发损失平均为24.6%;撒施尿素后立即灌水,氨挥发损失为19.7%,5h后灌水氨挥发损失为34.0%,增加了72.6%.     

Risk reduction measures of large wood accumulations at bridges

Environmental Fluid Mechanics - Bridges with and without piers are prone to large wood (LW) accumulations during floods, possibly resulting in an upstream backwater rise, local scour, or...     

Effects of ecotourism on forest loss in the Himalayan biodiversity hotspot based on counterfactual analyses

Ecotourism is developing rapidly in biodiversity hotspots worldwide, but there is limited and mixed empirical evidence that ecotourism achieves positive biodiversity outcomes. We assessed whether ecotourism influenced forest loss rates and trajectories from 2000 to 2017 in Himalayan temperate forests. We compared forest loss in 15 ecotourism hubs with nonecotourism areas in 4 Himalayan countries. We used matching statistics to control for local-level determinants of forest loss, for example, population density, market access, and topography. None of the ecotourism hubs was free of forest loss, and we found limited evidence that forest-loss trajectories in ecotourism hubs were different from those in nonecotourism areas. In Nepal and Bhutan, differences in forest loss rates between ecotourism hubs and matched nonecotourism areas did not differ significantly, and the magnitude of the estimated effect was small. In India, where overall forest loss rates were the lowest of any country in our analysis, forest loss rates were higher in ecotourism hubs than in matched nonecotourism areas. In contrast, in China, where overall forest loss rates were highest, forest loss rates were lower in ecotourism hubs than where there was no ecotourism. Our results suggest that the success of ecotourism as a forest conservation strategy, as it is currently practiced in the Himalaya, is context dependent. In a region with high deforestation pressures, ecotourism may be a relatively environmentally friendly form of economic development relative to other development strategies. However, ecotourism may stimulate forest loss in regions where deforestation rates are low.