Assigning results of the Tool for Sustainability Impact Assessment (ToSIA) to products of a forest-wood-chain

A Tool for Sustainability Impact Assessment (ToSIA) has been developed for assessing sustainability impacts of forest-wood-chains (FWCs). Sustainability is determined by analysing environmental, economic, and social sustainability indicators for all the production processes along the FWC. Results of the tool can be analysed at an aggregated level for complete FWCs, but for some applications it is useful to assign the indicator results to products of the chain.This paper presents a procedure in ToSIA to assign sustainability impacts to multiple output products of FWC. The procedure was tested and demonstrated with an example FWC from Scandinavia that included furniture and bio-energy production. Two different allocation criteria, carbon-based and economic value-based, were applied with different options for assigning the impacts on the sub-products of the chain. Three indicators representing the three pillars of the sustainability were chosen to demonstrate the procedure: production costs (economic), employment (social) and transport intensity (environmental).The results indicated that the allocation criteria greatly affect the indicator results assigned to the different products of FWCs. The selection of the allocation criterion depends on the question approached and on the availability of the needed process related data. The data availability is assured for the carbon-based allocation within ToSIA, as following the carbon flows within the chain is mandatory for any ToSIA application. Economic values of products, on the other hand, are more closely linked to the aims of the production processes of the value chains and are thereby meaningful allocation criteria in many cases. The allocation procedure of ToSIA was proved to be flexible allowing different criteria and still consistent in allocation of the various sustainability impacts of the FWCs.     

湿地生态系统硅生物地球化学循环研究进展

硅在地壳中的丰度仅次于氧,是地球表面大多数土壤和岩石的一种基本成分,也是水生植物（特别是硅藻类）以及多种作物生长所必需的营养元素,还是控制陆地、海洋、沿海和内陆水生态系统机能的重要营养元素。目前关于全球硅的生物地球化学循环的研究多集中在陆地和海洋两大生态系统,而湿地生态系统中硅的循环过程、储存量尚不清楚。虽然在河口湿地开展一些关于硅的相关研究,但是硅在湿地的循环机制研究不够全面,尤其相比碳、氮、磷等元素,硅素研究甚少。而且,国内关于硅的相关研究更为匮乏。本文在总结国内外关于湿地生态系统硅素研究的基础上,综述硅在湿地生态系统的存在形态与分布特征,阐述硅在湿地生态系统中的基本循环过程,列举影响硅在湿地生态系统中循环的主要因素,如：湿地类型、水淹时间、季节变化、人类干扰等;提出在今后研究工作中应进一步探索硅在湿地生态系统中迁移、转化的机制,加深研究人类活动对湿地生态系统硅循环的影响,特别是应该加强研究河口潮汐湿地和沿海湿地生态系统硅的生物地球化学循环过程和储存量,有助于明确湿地生态系统对于硅的截留量;并弄清湿地中碳与硅含量之间的关系,从水文学角度分析湿地中排水、蒸发、洪期及滞留时间等因素对硅循环的影响,从而试图建立湿地硅循环模型,有助于预测湿地生态系统硅循环对沿海地区赤潮等富营养化现象和全球气候变化的影响。     

Emerging electrochemical processes for materials recovery from wastewater: Mechanisms and prospects

• Mechanisms for selective recovery of materials in electrochemical processes are discussed. • Wastewaters that contain recoverable materials are reviewed. • Application prospects are discussed from both technical and non-technical aspects. Recovering valuable materials from waste streams is critical to the transition to a circular economy with reduced environmental damages caused by resource extraction activities. Municipal and industrial wastewaters contain a variety of materials, such as nutrients (nitrogen and phosphorus), lithium, and rare earth elements, which can be recovered as value-added products. Owing to their modularity, convenient operation and control, and the non-requirement of chemical dosage, electrochemical technologies offer a great promise for resource recovery in small-scale, decentralized systems. Here, we review three emerging electrochemical technologies for materials recovery applications: electrosorption based on carbonaceous and intercalation electrodes, electrochemical redox processes, and electrochemically induced precipitation. We highlight the mechanisms for achieving selective materials recovery in these processes. We also present an overview of the advantages and limitations of these technologies, as well as the key challenges that need to be overcome for their deployment in real-world systems to achieve cost-effective and sustainable materials recovery.     

抗生素抗性基因在生活及工业混合废水处理系统中的分布和去除

抗生素抗性基因(ARGs)由于其广泛的传播与转移,成为日益严峻的环境问题。污水处理厂(WWTP)被公认为ARGs的主要来源之一。膜生物反应器(MBR)是一种新型污染物去除工艺。在一个具有传统生物处理和膜系统处理的城镇污水处理系统的进水中,检出17种ARGs,并首次检出甲氧苄啶类ARGs。进水中sulΙ基因的绝对丰度最高,随后依次是tet C、sulⅡ、tet W、dfr A1、flo R和dfr A13基因。不同的处理系统去除同一种ARGs效果各不相同,MBR对ARGs去除效果显著优于传统生物处理工艺,同一个处理系统处理不同类ARGs,四环素类ARGs被去除的效果显著优于其他ARGs被去除的效果,绝对丰度下降了3.8个数量级。ARGs没有真正意义上的去除,只是从水体转移到污泥中,污泥中的ARGs不断积累。     

Modeling Biochemical Oxygen Demand Through the Middle and Lower Savannah River1

Abstract: In order to improve modeling accuracy and general understanding of lotic biochemical oxygen demand (BOD), this study characterized river metabolism with the current Georgia Environmental Protection Division method for the middle and lower Savannah River basin (MLSRB) and several alternative methods developed with 120‐day, long‐term biochemical oxygen demand (LTBOD) data from the MLSRB. The data were a subset of a larger two‐year LTBOD study to characterize and understand BOD in the MLSRB, located approximately between Augusta, Georgia, and Savannah, Georgia, along the border of Georgia and South Carolina. The LTBOD data included total oxygen loss and nitrogen speciation for separately quantifying nitrification. Results support the following insights and opportunities for modeling methods: (1) it is important to modeling accuracy that residuals be checked for even dispersion to avoid areas of over‐ and underprediction; (2) modeling with bounded, yet unfixed, rates is a sufficiently simple alternative to fixed‐rate modeling that can eliminate the need for manual adjustments and provide additional system understanding to inform regulation; (3) if fixed rates modeling is desired, model quality for this system might be improved through revising the current low rate (along with the associated f‐ratio updates) from 0.02/day rate to 0.006/day and potentially adding a new rate at 1.0/day in some cases; and (4) the current 57/43 ratio of slow/fast BOD is reasonable based on the 52/45/3 slow/fast/faster BOD proportions of this study.     

Influence of Small Dams on Downstream Channel Characteristics in Pennsylvania and Maryland: Implications for the Long‐Term Geomorphic Effects of Dam Removal1

Abstract: We evaluate the effects of small dams (11 of 15 sites less than 4 m high) on downstream channels at 15 sites in Maryland and Pennsylvania by using a reach upstream of the reservoir at each site to represent the downstream reach before dam construction. A semi‐quantitative geomorphic characterization demonstrates that upstream reaches occupy similar geomorphic settings as downstream reaches. Survey data indicate that dams have had no measurable influence on the water surface slope, width, and the percentages of exposed bedrock or boulders on the streambed. The median grain diameter (D₅₀) is increased slightly by dam construction, but D₅₀ remains within the pebble size class. The percentage of sand and silt and clay on the bed averages about 35% before dam construction, but typically decreases to around 20% after dam construction. The presence of the dam has therefore only influenced the fraction of finer‐grained sediment on the bed, and has not caused other measurable changes in fluvial morphology. The absence of measurable geomorphic change from dam impacts is explicable given the extent of geologic control at these study sites. We speculate that potential changes that could have been induced by dam construction have been resisted by inerodible bedrock, relatively immobile boulders, well‐vegetated and cohesive banks, and low rates of bed material supply and transport. If the dams of our study are removed, we argue that long‐term changes (those that remain after a period of transient adjustment) will be limited to increases in the percentage of sand and silt and clay on the bed. Thus, dam removal in streams similar to those of our study area should not result in significant long‐term geomorphic changes.     

Legacy Effects of Colonial Millponds on Floodplain Sedimentation,Bank Erosion,and Channel Morphology,Mid‐Atlantic,USA1

Abstract: Many rivers and streams of the Mid‐Atlantic Region, United States (U.S.) have been altered by postcolonial floodplain sedimentation (legacy sediment) associated with numerous milldams. Little Conestoga Creek, Pennsylvania, a tributary to the Susquehanna River and the Chesapeake Bay, is one of these streams. Floodplain sedimentation rates, bank erosion rates, and channel morphology were measured annually during 2004‐2007 at five sites along a 28‐km length of Little Conestoga Creek with nine colonial era milldams (one dam was still in place in 2007). This study was part of a larger cooperative effort to quantify floodplain sedimentation, bank erosion, and channel morphology in a high sediment yielding region of the Chesapeake Bay watershed. Data from the five sites were used to estimate the annual volume and mass of sediment stored on the floodplain and eroded from the banks for 14 segments along the 28‐km length of creek. A bank and floodplain reach based sediment budget (sediment budget) was constructed for the 28 km by summing the net volume of sediment deposited and eroded from each segment. Mean floodplain sedimentation rates for Little Conestoga Creek were variable, with erosion at one upstream site (?5 mm/year) to deposition at the other four sites (highest = 11 mm/year) despite over a meter of floodplain aggradation from postcolonial sedimentation. Mean bank erosion rates range between 29 and 163 mm/year among the five sites. Bank height increased 1 m for every 10.6 m of channel width, from upstream to downstream (R² = 0.79, p < 0.0001) resulting in progressively lowered hydraulic connectivity between the channel and the floodplain. Floodplain sedimentation and bank erosion rates also appear to be affected by the proximity of the segments to one existing milldam, which promotes deposition upstream and scouring downstream. The floodplain and bank along the 28‐km reach produced a net mean sediment loss of 5,634 Mg/year for 2004‐2007, indicating that bank erosion was exceeding floodplain sedimentation. In particular, the three segments between the existing dam and the confluence with the Conestoga River (32% of the studied reach) account for 97% of the measured net sediment budget. Future research directed at understanding channel equilibria should facilitate efforts to reduce the sediment impacts of dam removal and legacy sediment.     

A Critical Appraisal of Field Evidence From A Regional Survey for Acid Deposition Effects On Scottish Moorland Podzols

Samples have been collected from major horizons of 34 podzol profiles distributed throughout Scotland, all developed from granite or granitic tills and under Calluna moorland. the pH in water and calcium chloride pastes, exchangeable cations and cation exchange capacity, and extractable aluminium of the soils collected have been measured, and the results studied in relation to reported atmospheric deposition of H⁺, non-marine sulphur and nitrate. for all horizons, significant positive correlations were found between soil pH and rainfall mean pH, as might be expected when the critical load of H⁺ deposition is exceeded. Acidifying pollutant deposition also apparently increased soil extractable aluminium concentrations in the B and C horizons. However, exchangeable base cation concentrations tended to increase, rather than decrease, with increasing precipitation acidity. This effect was attributed to increases in biogeochemical cycling of base cations, increases in leaching inputs of base cations from overlying A/E horizon soils, and increases in the inputs of base cations leached from upslope. the results suggest that the simple steady state mass approach to the quantification of critical loads, as often applied, may be an oversimplification.     

土-岩界面重金属行为的研究进展

随着多环境介质问题研究的深入,重金属在跨介质迁移时产生的界面效应问题倍受人们关注。土－岩界面因其特有的微环境结构和特性,使重金属在该界面的行为过程既部分地表现出与在两侧的环境介质运移过程的动力学特征及机制,又有其独特的特性。有关研究表明自然因素及人为活动等引起的环境参数的变化对土－岩界面的重金属行为有显著影响。今后土－岩界面的重金属行为研究应在目前研究状况的基础上立足于为土壤污染的修复提供技术支撑。     

A planning and decision-making framework for ecological restoration

A broad and objective perspective of ecological and socioenomic knowledge is required to underlie a scientific approach to the problems of terrestrial restoration ecology. Uncertainty associated with limited scientific knowledge highlights the crucial importance of the interaction between science and policy in weighing ecological restoration alternatives in relation to other management options. In this paper, we provide a pragmatic definition for restoration ecology that is suitable for extensive terrestrial applications and present a decision framework to help organize and clarify different phases of the decision process as it is related to ecological restoration. We argue that restoration planning should include a wider spectrum of participants and decisions than have traditionally been employed.