144 research outputs found

    SOURCES OF COPPER INTO THE EUROPEAN AQUATIC ENVIRONMENT.

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    Chemical contamination from point source discharges in developed (resource-rich) countries has been widely regulated and studied for decades; however, diffuse sources are largely unregulated and widespread. In the European Union, large dischargers report releases of some chemicals; yet, little is known of total emissions (point and diffuse) and their relative significance. We estimated copper loadings from all significant sources including industry, sewage treatment plants, surface runoff (from traffic, architecture and atmospheric deposition), septic tanks, agriculture, mariculture, marine transport (antifoulant leaching), and natural processes. A combination of European datasets, literature and industry data were utilised to generate export coefficients. These were then multiplied by activity rates to derive loads. A total of around 8 kilotons of copper per annum (ktpa) is estimated to enter freshwaters in the European Union and another 3.5 ktpa enters transitional and coastal waters. The main inputs to freshwater are natural processes (3.7 ktpa), agriculture (1.8 ktpa) and runoff (1.8 ktpa). Agricultural emissions are dominated by copper-based plant protection products and farmyard manure. Urban runoff is influenced by copper use in architecture and by vehicle brake linings. Antifoulant leaching from boats (3.2 ktpa) dominates saline water loads of copper. It is noteworthy that most of the emissions originate from a limited number of copper uses where environmental exposure and pathways exist, compared with the bulk of copper use within electrical and electronic equipment and infrastructure that has no environmental pathway during its use. A sensitivity analysis indicated significant uncertainty in data from abandoned mines and urban runoff load estimates. This study provided for the first time a methodology and comprehensive metal load apportionment to European aquatic systems, identifying data gaps and uncertainties which may be refined over time. Source apportionments using this methodology can inform more cost-effective environmental risk assessment and management. This article is protected by copyright. All rights reserved. © 2022 SETAC

    Towards a rhizomatic understanding of the desistance journey

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    Although the ‘desistance as a (zigzag) journey’ metaphor has proved useful in terms of translating theory into practice, this article makes the case that it is insufficient for conveying the truly complex, social, unpredictable and ‘messy’ process of desistance from crime. The article uses what we know about the process of desistance to discuss the utility of Deleuze and Guattari’s (2013) rhizomatic theory in recasting the desistance journey metaphor. In doing so it is suggested that the desistance journey should be understood in terms of its endless and multiplicitous nature, a symbol of metamorphosis, and it argues that our focus should be on understanding the ‘desister as nomad’. This, the article concludes, holds important ramifications for the way in which we understand and implement desistance-focused practice in the criminal justice system

    The transfer and fate of Pb from sewage sludge amended soil in a multi-trophic food chain: a comparison with the labile elements Cd and Zn

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    The contamination of agroecosystems due to the presence of trace elements in commonly used agricultural materials is a serious issue. The most contaminated material is usually sewage sludge, and the sustainable use of this material within agriculture is a major concern. This study addresses a key issue in this respect, the fate of trace metals applied to soil in food chains. The work particularly addresses the transfer of Pb, which is an understudied element in this respect, and compares the transfer of Pb with two of the most labile metals, Cd and Zn. The transfer of these elements was determined from sludge-amended soils in a food chain consisting of Indian mustard (Brassica juncea), the mustard aphid (Lipaphis erysimi) and a predatory beetle (Coccinella septempunctata). The soil was amended with sludge at rates of 0, 5, 10 and 20 % (w/w). Results showed that Cd was readily transferred through the food chain until the predator trophic level. Zn was the most readily transferred element in the lower trophic levels, but transfer to aphids was effectively restricted by the plant regulating shoot concentration. Pb had the lowest level of transfer from soil to shoot and exhibited particular retention in the roots. Nevertheless, Pb concentrations were significantly increased by sludge amendment in aphids, and Pb was increasingly transferred to ladybirds as levels increased. The potential for Pb to cause secondary toxicity to organisms in higher trophic levels may have therefore been underestimated

    Atmospheric Ice‐Nucleating Particles in the Dusty Tropical Atlantic

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    Desert dust is one of the most important atmospheric ice-nucleating aerosol species around the globe. However, there have been very few measurements of ice-nucleating particle (INP) concentrations in dusty air close to desert sources. In this study we report the concentration of INPs in dust laden air over the tropical Atlantic within a few days' transport of one of the world's most important atmospheric sources of desert dust, the Sahara. These measurements were performed as part of the Ice in Clouds Experiment-Dust campaign based in Cape Verde, during August 2015. INP concentrations active in the immersion mode, determined using a droplet-on-filter technique, ranged from around 10² m⁻³ at -12°C to around 10⁵ m⁻³ at -23°C. There is about 2 orders of magnitude variability in INP concentration for a particular temperature, which is determined largely by the variability in atmospheric dust loading. These measurements were made at altitudes from 30 to 3,500 m in air containing a range of dust loadings. The ice active site density (n s ) for desert dust dominated aerosol derived from our measurements agrees with several laboratory-based parameterizations for ice nucleation by desert dust within 1 to 2 orders of magnitude. The small variability in n s values determined from our measurements (within about 1 order of magnitude) is striking given that the back trajectory analysis suggests that the sources of dust were geographically diverse. This is consistent with previous work, which indicates that desert dust's ice-nucleating activity is only weakly dependent on source

    An Integrated Architecture for Aircraft Engine Performance Monitoring and Fault Diagnostics: Engine Test Results

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    This paper presents a model-based architecture for performance trend monitoring and gas path fault diagnostics designed for analyzing streaming transient aircraft engine measurement data. The technique analyzes residuals between sensed engine outputs and model predicted outputs for fault detection and isolation purposes. Diagnostic results from the application of the approach to test data acquired from an aircraft turbofan engine are presented. The approach is found to avoid false alarms when presented nominal fault-free data. Additionally, the approach is found to successfully detect and isolate gas path seeded-faults under steady-state operating scenarios although some fault misclassifications are noted during engine transients. Recommendations for follow-on maturation and evaluation of the technique are also presented

    Potentially toxic metals in historic landfill sites: Implications for grazing animals

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    Municipal waste disposal is an increasing global problem, frequently solved by the use of landfill sites. Following closure, such sites contain a legacy of pollutants and must be managed to provide a safe and useful end life. The soils and vegetation from four historic landfill sites were analysed to determine the extent of pollution by potentially toxic metals (PTMs). Data were subsequently assessed to determine if post closure uses involving grazing were safe for the animals. The heaviest and widest spread soil contamination was due to Ni. Concentrations at all sites exceeded the 95th percentile value for rural soils, in one case by a factor of 30. Cu and Pb contamination was identified at some sites, but no evidence of Al or Zn contamination was found. Oral bioaccessibility testing showed that the availability of Ni in soil was exceedingly low, whilst that of Cu and Pb was high. Concentrations in plant shoots differed significantly amongst the sites, but interspecific differences in shoot concentration were only significant in the case of Cu. The results indicated that exposure levels to grazers would be at or below tolerable levels, indicating that it is generally safe to graze historic landfill. However, animals could be exposed to higher levels of PTMs than would be expected from rural locations, and grazing under conditions where soil consumption may be high could result in levels of exposure to Al, Ni and Pb exceeding tolerable levels. © Springer International Publishing 2014

    Juvenile Hormone (JH) Esterase of the Mosquito Culex quinquefasciatus Is Not a Target of the JH Analog Insecticide Methoprene

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    Juvenile hormones (JHs) are essential sesquiterpenes that control insect development and reproduction. JH analog (JHA) insecticides such as methoprene are compounds that mimic the structure and/or biological activity of JH. In this study we obtained a full-length cDNA, cqjhe, from the southern house mosquito Culex quinquefasciatus that encodes CqJHE, an esterase that selectively metabolizes JH. Unlike other recombinant esterases that have been identified from dipteran insects, CqJHE hydrolyzed JH with specificity constant (kcat/KM ratio) and Vmax values that are common among JH esterases (JHEs). CqJHE showed picomolar sensitivity to OTFP, a JHE-selective inhibitor, but more than 1000-fold lower sensitivity to DFP, a general esterase inhibitor. To our surprise, CqJHE did not metabolize the isopropyl ester of methoprene even when 25 pmol of methoprene was incubated with an amount of CqJHE that was sufficient to hydrolyze 7,200 pmol of JH to JH acid under the same assay conditions. In competition assays in which both JH and methoprene were available to CqJHE, methoprene did not show any inhibitory effects on the JH hydrolysis rate even when methoprene was present in the assay at a 10-fold higher concentration relative to JH. Our findings indicated that JHE is not a molecular target of methoprene. Our findings also do not support the hypothesis that methoprene functions in part by inhibiting the action of JHE
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