Positive vs. false detection: A comparison of analytical methods and performance for analysis of cyclic volatile methylsiloxanes (cVMS) in environmental samples from remote regions

Contamination and analytical variation can significantly hinder trace analysis of cyclic methyl volatile siloxanes (cVMS); potentially resulting in the report of false positives at concentrations approaching detection limits. To assess detection and variation associated with trace cVMS analysis in environmental matrices, a co-operative laboratory comparison for the analysis of octametylcyclotetrasiloxane (D4), decamethylcylcopentasiloxane (D5), and dodecametylcyclohexasiloxane (D6) in sediment and biota from the Svalbard Archipelago was conducted. Two definitions of detection limits were evaluated in this study; method detection limits (MDL, matrix defined) and limits of detection (LOD, solvent defined). D5 was the only cVMS detected above both LOD (0.08–0.81 ng g⁻¹ ww) and MDL (0.47–2.36 ng g⁻¹ ww) within sediment by all laboratories where concentrations ranged from 0.55 to 3.91 ng g⁻¹ ww. The percentage of positive detects for D5 decreased by 80% when MDL was defined as the detection limit. D5 was also detected at the highest frequency among all laboratories in fish liver with concentrations ranging from 0.72 to 345 ng g⁻¹ ww. Similar to sediment, percentage of positive detects for D5 decreased by 60% across all laboratories for fish livers when using MDL (0.68–3.49 ng g⁻¹ ww). Similar observations were seen with both D4 and D6, indicating that sample matrix significantly contributes to analytical response variation. Despite differences in analytical methods used between laboratories, good agreement was obtained when using MDL to define detection limits. This study shows the importance of incorporating variation introduced by sample matrices into detection limit calculations to insure data accuracy of cVMS at low concentrations.     

垂直流人工湿地系统中水流规律的研究

对一种新型的垂直流人工湿地系统的水流特性进行了研究。考察了系统的运行状况及介质中滞留区的分布范围，并且运用化学工程中反应器理论，采用示踪剂试验的方法得到了垂直流人工湿地系统的停留时间分布与污水的实际停留时间。根据水流停留时间分布函数对系统实际液流流态进行了数学模拟，提出二级串联的理想完全混合反应器（CSTR）模型能够较好地模拟垂直流人工湿地系统中水流的流动形态。     

An overdue alignment of risk and resilience? A conceptual contribution to community resilience

A systematic review of literature on community resilience measurement published between 2005 and 2014 revealed that the profound lack of clarity on risk and resilience is one of the main reasons why confusion about terms such as adaptive capacity, resilience, and vulnerability persists, despite the effort spared to operationalise these concepts. Resilience is measured in isolation in some cases, where a shock is perceived to arise external to the system of interest. Problematically, this contradicts the way in which the climate change and disaster communities perceive risk as manifesting itself endogenously as a function of exposure, hazard, and vulnerability. The common conceptualisation of resilience as predominantly positive is problematic as well when, in reality, many undesirable properties of a system are resilient. Consequently, this paper presents an integrative framework that highlights the interactions between risk drivers and coping, adaptive, and transformative capacities, providing an improved conceptual basis for resilience measurement.     

Concentrations and specific loads of UV filters in sewage sludge originating from a monitoring network in Switzerland

Many substances related to human activities end up in wastewater and accumulate in sewage sludge. The present study focuses on the analysis of widely used UV filters 3-(4-methylbenzylidene) camphor (4-MBC), octyl-methoxycinnamate (OMC), octocrylene (OC) and octyl-triazone (OT) in sewage sludge originating from a monitoring network in Switzerland. Mean concentrations in stabilised sludge from 14 wastewater treatment plants were 1780, 110, 4840 and 5510 microg/kg dry matter for 4-MBC, OMC, OC and OT, respectively. Specific loads in sewage sludge show that UV filters originate mainly from private households, but surface runoff and industries may be considered as additional sources. This indicates that besides use for sunscreens and cosmetics UV filters might occur in plastics and other materials and be released to the environment by volatilization or leaching. Differences between the modeled per capita loads of UV filters in sewage sludge and the observed specific loads in sewage sludge are probably due to erroneous figures of production volumes, degradation and sorption during wastewater treatment as well as degradation processes during transport in the sewer or sludge treatment. Thus, further research is needed to elucidate the fate of UV filters after application and release into the environment. Other compounds used as UV filters should be included in future studies.     

Climate change mitigation in Austria and Switzerland: The pitfalls of federalism in greening decentralized building policies

The present paper analyses and compares how federalism in Austria and Switzerland affected climate change mitigation in the fully decentralized building sectors of the two countries during the Kyoto Period (1990–2012). This is of interest because the environmental significance of federal political systems is still contested. We first review the literature on federalism in the context of environmental and climate policymaking, and we show that the effects of federal political systems can be positive or negative (depending on interactions between politics and problem characteristics). We then summarize the two qualitative country studies. By analysing who initiated and coordinated respective policies at what time and why, we show that respective policy changes neither emerged bottom-up nor diffused between provinces/cantons, although the latter are fully responsible for building policies. While most policy changes were triggered by federal and/or European Union interventions, the provinces/cantons usually delayed and/or watered down policy changes to smallest common denominator solutions. Based on these findings we conclude that the building sectors of the two countries became more efficient despite, not because of federalism. Against this background we recommend centralizing building policies, or to engage sub-national actors in national target-setting early on.     

反应器理论在复合垂直流构建湿地水流流态研究中的应用

运用反应器理论研究了一种新型的复合垂直流构建湿地系统(IVCW)的水流流态,由示踪剂试验得到水流停留时间分布(RTD),从而确定了IVCW在水力负荷为200～800mm/d时,停留时间为19～35h,并由RTD曲线的特征值确定IVCW的水流流态介于理想推流与完全混合流之间,同时应用离散流模型,不仅较好地模拟了IVCW的实际水流流态,还得到了水流的Peclect准数在11～19之间.通过有植物与无植物系统的对照发现植物根系有利于IVCW的水流流态接近理想推流状态.     

Global environmental consequences of increased biodiesel consumption in Switzerland: consequential life cycle assessment

This study assesses the direct and indirect environmental impacts to be expected if Switzerland should replace one percent of its current diesel consumption with imports of A) soybean methyl ester (SME) from Brazil, or B) palm methyl ester (PME) from Malaysia. In order to take into account possible future consequences, what-if scenarios were developed and assessed by means of a consequential LCA. In contrast to attributional LCA, the consequential approach uses system enlargement to include the marginal products affected by a change of the physical flows in the central life cycle. This means that the LCA considers all inputs and outputs which are linked to biodiesel production and that the product system is subsequently expanded to include the marginal products affected. Both future systems are assessed in comparison with the environmental scores of the fossil equivalent to biodiesel, i.e. diesel low in sulphur. The environmental burdens are measured by means of greenhouse gas emissions (GHG), land occupation and various non-aggregated and aggregated environmental impact indicators.In sum, the environmental impacts of an increased SME consumption depend on the environmental scores of the marginal replacement products on the world market, rather than on local production factors. In other words, the marginal products assumed to be affected are most important for the results obtained, i.e. in particular the marginal vegetable oil, fodder cake and land areas. In this study it is SME production increased at the expense of the available soybean oil which shifts the impacts associated with soybean oil production to the production of the marginal vegetable oils on the world market. In this perspective, it is not relevant in which country biodiesel production takes place, but rather which vegetable oil is involved. With respect to PME, the most relevant determining factor for the environmental impacts is the land area affected by the increased cultivation of oil palms. Currently, this expansion displaces primarily peat land and rain forest. This causes GHG emissions which are much higher than the emissions of the fossil reference. All in all, both PME from Malaysia and SME from Brazil cause more environmental impact than allowed by the Swiss tax redemption on agro-biofuels (max. 60% GHG emissions and 125% UBP of the fossil reference).     

What if Dutch investors started worrying about flood risk? Implications for disaster risk reduction

Regional Environmental Change - Increasingly, roles and responsibilities of the public sector in flood risk management are receiving attention in research and policy. Part of the debate suggests...