Preliminary characterization and source assessment of PAHs in tributary sediments of the Athabasca River,Canada

The Athabasca Oil Sands are one of four natural oil sands deposits in Northern Alberta, Canada. As a number of new mines are planned in the area, there is a need to establish background levels of natural hydrocarbon release prior to these developments. To this end, various environmental samples were taken from selected tributaries in the oil sands region of the Athabasca River Basin and analysed by gas chromatography/mass spectrometry (GC/MS) for polycyclic aromatic hydrocarbons (PAHs) and their alkylated analogues. Samples were collected over 3 years (1998-2000) to provide an increased understanding of the spatial distribution, nature and extent of natural hydrocarbon release to the environment. Results indicated that levels of total PAHs were elevated in the tributaries (up to 34.7 µg/g) compared to the main stem Athabasca River (<2 µg/g). As expected, samples from the oil sands deposits contained the greatest amounts of PAHs and alkylated PAHs. Profiles of the alkylated PAM distributions were very similar, indicating that all the samples tested were from a common petrogenic source.     

Urban Transitions: On Urban Resilience and Human-Dominated Ecosystems

Urbanization is a global multidimensional process paired with increasing uncertainty due to climate change, migration of people, and changes in the capacity to sustain ecosystem services. This article lays a foundation for discussing transitions in urban governance, which enable cities to navigate change, build capacity to withstand shocks, and use experimentation and innovation in face of uncertainty. Using the three concrete case cities—New Orleans, Cape Town, and Phoenix—the article analyzes thresholds and cross-scale interactions, and expands the scale at which urban resilience has been discussed by integrating the idea from geography that cities form part of “system of cities” (i.e., they cannot be seen as single entities). Based on this, the article argues that urban governance need to harness social networks of urban innovation to sustain ecosystem services, while nurturing discourses that situate the city as part of regional ecosystems. The article broadens the discussion on urban resilience while challenging resilience theory when addressing human-dominated ecosystems. Practical examples of harnessing urban innovation are presented, paired with an agenda for research and policy.     

Extractability and mobility of mercury from agricultural soils surrounding industrial and mining contaminated areas

This study focussed on a comparison of the extractability of mercury in soils with two different contamination sources (a chlor-alkali plant and mining activities) and on the evaluation of the influence of specific soil properties on the behaviour of the contaminant. The method applied here did not target the identification of individual species, but instead provided information concerning the mobility of mercury species in soil. Mercury fractions were classified as mobile, semi-mobile and non-mobile. The fractionation study revealed that in all samples mercury was mainly present in the semi-mobile phase (between 63% and 97%). The highest mercury mobility (2.7 mg kg(-1)) was found in soils from the industrial area. Mining soils exhibited higher percentage of non-mobile mercury, up to 35%, due to their elevated sulfur content. Results of factor analysis indicate that the presence of mercury in the mobile phase could be related to manganese and aluminium soil contents. A positive relation between mercury in the semi-mobile fraction and the aluminium content was also observed. By contrary, organic matter and sulfur contents contributed to mercury retention in the soil matrix reducing the mobility of the metal. Despite known limitations of sequential extraction procedures, the methodology applied in this study for the fractionation of mercury in contaminated soil samples provided relevant information on mercury's relative mobility.     

Squaring the Circle? Combining Models, Indicators, Experts and End-Users in Integrated Land-Use Management Support Tools

The most important challenges faced in the field of integrated land-use management are (i) harmonizing and integrating different datasets, (ii) selecting appropriate indicators, (iii) fitting suitable models to adequate scales, and finally (iv) integrating data, indicators and models into systems that allow both a high level of participation and flexibility with the adaptation to a variety of questions and applications. The articles of this special issue “Squaring the Circle? Combining Models, Indicators, Experts and End-Users in Integrated Land-Use Management Support Tools” demonstrate the challenges that are related to this topic. The case studies present examples of such integrated systems in order to recommend best practices to support land-use management and to reveal existing shortcomings. As a conclusion, seven features of a successful applicable integrated land-use management support system are derived: (1) ability to deal with discontinuity in information and datasets, (2) contribution to solve the problem of indicator diversity, (3) structuring the decision-making process, (4) support of participation processes in generating decisions, (5) development, comparison and evaluation of land-use alternatives, (6) assessment of the efficiency and trade-offs of management options, and (7) assistance of stakeholders in group communication processes.     

Behavioural and biochemical responses of two marine invertebrates Scrobicularia plana and Hediste diversicolor to copper oxide nanoparticles

Engineered nano-sized Cu oxide particles are extensively used in diverse applications. Because aquatic environments are the ultimate “sink” for all contaminants, it is expected that nanoparticles (NP) will follow the same fate. In this study, two marine invertebrates Scrobicularia plana and Hediste diversicolor were chosen as ecotoxicological models. The aim was to evaluate behavioural (burrowing kinetics, feeding rate) and biochemical (biomarkers) responses of S. plana and H. diversicolor exposed in the laboratory to Cu (10 μg L⁻¹) added in natural seawater either in the form of engineered nanoparticles (NPs) of CuO or as dissolved Cu in 2% HNO₃. Exposure was characterized by considering (i) the physico-chemical fate of NP (ii) the fraction of labile Cu in experimental media and (iii) Cu bioaccumulation. Results showed high aggregation of CuO NPs in seawater and no additional bioavailable Cu concentrations. Behavioural impairments were observed in S. plana exposed to CuO NPs or soluble Cu whereas in H. diversicolor, only the exposure to soluble Cu led to a burrowing decrease. No obvious neurotoxicity effects were revealed since in both species, no changes in cholinesterasic activity occurred in response to both forms of Cu exposure. Biomarkers of oxidative-stress catalase and glutathione-S-transferase were enhanced in both species whereas superoxide dismutase was increased only in S. plana exposed to CuO NPs. Metallothionein-like protein was increased in bivalves exposed to both forms of Cu. Since, no detectable release of soluble Cu from CuO NPs occurred during the time of experiment, ecotoxicity effects seem to be related to CuO NPs themselves.     

Polycyclic aromatic hydrocarbons and hydroxylated metabolites in the muscle tissue of Eurasian perch (Perca fluviatilis) through dietary exposure during a 56-day period

Eurasian perch (Perca fluviatilis) was exposed trophically to phenanthrene, pyrene and benzo[a]pyrene. Accumulation kinetics in the muscle tissue of parent PAHs and hydroxylated metabolites were established for 56 days at 3 levels of exposure (0, 100 and 500 μg/kg BW). Benzo[a]pyrene and 3-hydroxy-benzo[a]pyrene were not detected in the muscles. During exposure, there was an increase in phenanthrene, pyrene and their hydroxylated metabolites in the muscle tissue. Low transfer to muscle tissue was observed at equilibrium for phenanthrene (4.4 ± 0.6% and 2.7 ± 0.8%) and pyrene (1.0 ± 0.2% and 0.33 ± 0.09%), depending on the concentrations in the spiked feed.     

Monitoring plastic ingestion by the northern fulmar Fulmarus glacialis in the North Sea

The abundance of plastics in stomachs of northern fulmars from the North Sea is used in the OSPAR Ecological Quality Objective (EcoQO) for marine litter. The preliminary EcoQO defines acceptable ecological quality as the situation where no more than 10% of fulmars exceed a critical level of 0.1 g of plastic in the stomach. During 2003-2007, 95% of 1295 fulmars sampled in the North Sea had plastic in the stomach (on average 35 pieces weighing 0.31 g) and the critical level of 0.1 g of plastic was exceeded by 58% of birds, with regional variations ranging from 48 to 78%. Long term data for the Netherlands since the 1980s show a decrease of industrial, but an increase of user plastics, with shipping and fisheries as the main sources. The EcoQO is now also used as an indicator for Good Environmental Status in the European Marine Strategy Framework Directive.     

Bestimmung von Mineralölkohlenwasserstoffen in Bodenproben mit Hilfe der Dünnschichtchromatographie

A thin-layer chromatographic method for the determination of mineral oil hydrocarbons (aliphatic compounds and naphtenes) of medium and low volatility in soil samples is presented which is based on their separation and quantitative determination. The extraction of the soil samples is effected by means of an n-hexane-acetone mixture (10∶1) supported by ultrasonics. The evaluation can be made visually or densitometrically by means of a thin-layer scanner. The applicability and restrictions of the method are shown. The advantage of the method lies in its low requirements pertaining to apparatus and chemicals, as well as in its rapidness which makes it suitable for quick in-situ analyses as, for example, for the assessment of the mineral oil content of a contaminated site.     

Bewertungskriterien des Umweltbundesamtes: Auswirkungen von Pflanzenschutzmitteln auf terrestrische Arthropoden

The fundamental data requirements for the authorization of plant protection products and the inclusion of active ingredients in Annex I of Council Directive 91/414/EEC are described in the Annexes II and III of the Directive. Definite guidelines concerning investigations with arthropods are partially deficient. The uniform principles for the registration of plant protection products in the Member States described in Annex VI of the directive were primarily developed to assess the effects on the beneficial capacity of arthropods in agriculture. However, the risk for arthopods as an essential part of the environment need to be assessed, too. Hence, the German Federal Environmental Agency has developed a tiered approach to assess the effects of plant protection products on arthopods based on the data requirements of Annex II and III of the Directive 91/414/EEC. The risk is assessed using the effect-concentration evaluated in ecotoxicological tests and the environmental concentration predicted by validated exposure models. To protect non-target species in terrestrial ecosystems assessment factors need to be considered.