Time filter

Source Type

Voss A.,University of Kassel | Alcamo J.,United Nations Environment Programme UNEP | Barlund I.,University of Kassel | Barlund I.,Helmholtz Center for Environmental Research | And 4 more authors.
Hydrological Processes | Year: 2012

To address the continental and large-scale aspects of water quality assessments, new modelling approaches are required. This paper describes the development of a continental-scale model of river water quality - WorldQual. Simple equations, consistent with the availability of data on the continental-scale, are used to simulate the response of biochemical oxygen demand (BOD 5) and total dissolved solids (TDS) to anthropogenic loadings and flow dilution. A methodology is developed that is appropriate for scenario analysis on the continental and global scale. Average monthly river water quality is modelled on a 5arcmin grid covering all Europe. Loadings are derived from assumptions about water use, return flows and other variables. The model WorldQual is tested against measured longitudinal gradients and time series data at specific river locations. The model performance on European scale shows that a good fit can be reached when using concentration classifications as a measure: For BOD 5, 51% of the simulated data is in the same quality class as the measurements and 30% differ only by one water-quality class; for TDS, the respective values are 35% and 41%. WorldQual was applied to investigate the impact of climate change on resulting changes of in-stream concentrations. The results for Europe show that future climate changes only have a small impact on European in-stream concentration levels of BOD 5, except for the Eastern part and the Black Sea region. This effect is stronger for the IPCM4-A2 scenario than for the MIMR-A2 scenario. © 2012 John Wiley & Sons, Ltd. Source

van den Berg M.,University Utrecht | Denison M.S.,University of California at Davis | Birnbaum L.S.,U.S. National Cancer Institute | DeVito M.J.,U.S. National Cancer Institute | And 9 more authors.
Toxicological Sciences | Year: 2013

In 2011, a joint World Health Organization (WHO) and United Nations Environment Programme (UNEP) expert consultation took place, during which the possible inclusion of brominated analogues of the dioxin-like compounds in the WHO Toxicity Equivalency Factor (TEF) scheme was evaluated. The expert panel concluded that polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs), and some dioxin-like biphenyls (dl-PBBs) may contribute significantly in daily human background exposure to the total dioxin toxic equivalencies (TEQs). These compounds are also commonly found in the aquatic environment. Available data for fish toxicity were evaluated for possible inclusion in the WHO-UNEP TEF scheme (van den Berg et al., 1998). Because of the limited database, it was decided not to derive specific WHO-UNEP TEFs for fish, but for ecotoxicological risk assessment, the use of specific relative effect potencies (REPs) from fish embryo assays is recommended. Based on the limited mammalian REP database for these brominated compounds, it was concluded that sufficient differentiation from the present TEF values of the chlorinated analogues (van den Berg et al., 2006) was not possible. However, the REPs for PBDDs, PBDFs, and non-ortho dl-PBBs in mammals closely follow those of the chlorinated analogues, at least within one order of magnitude. Therefore, the use of similar interim TEF values for brominated and chlorinated congeners for human risk assessment is recommended, pending more detailed information in the future. © The Author 2013. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. Source

Bruch C.,Environmental Law Institute ELI | Boulicault M.,ELI | Talati S.,ELI | Jensen D.,United Nations Environment Programme UNEP
Review of European Community and International Environmental Law | Year: 2012

Since the end of the Cold War, peacebuilding efforts and international environmental law have developed independently and in very different manners. Experiences in managing natural resources to support post-conflict peacebuilding in dozens of countries over the past twenty years, however, highlight the critical role that natural resources often play. The 2012 United Nations Conference on Sustainable Development (Rio+20) provides an opportunity to consider the lessons from these experiences and provide a vision for future consolidation of approaches. This article reviews the development of peacebuilding, highlighting the importance of natural resources. It then surveys the status of international law governing post-conflict peacebuilding, including international environmental law. Looking forward, it considers the likely directions of international law in governing post-conflict peacebuilding, concluding with thoughts on how to capitalize on Rio+20 to advance more effective approaches. © 2012 Blackwell Publishing Ltd. Source

Kinuthia-Njenga C.,United Nations Environment Programme UNEP
Regional Development Dialogue | Year: 2011

Cecilia Kinuthia-Njenga focuses on challenges with climate change adaptation in informal settlements in Nairobi, Kenya. Flooding is a major problem in most informal settlements in Nairobi. Many long-term inhabitants of slums, such as Mabatini in Mathare, state that floods now occur in places where they did not two decades ago. Climate change has increased the vulnerability of the urban poor living in Nairobi's informal settlements. Already they are forced to live in hazardous places. Many build their homes and grow their food on river flood plains and on steep, unstable hillsides. Provision and maintenance of infrastructure has been a major problem, especially within the low-income urban settlements. The urban poor and slumdwellers in Nairobi are the ones who suffer most from lack of piped water supply. Environmental immigrants from climate-related droughts and floods are already swelling the tide of rural-to-urban migration in Nairobi slums. Source

Del Valle H.F.,CONICET | Blanco P.D.,CONICET | Metternicht G.I.,United Nations Environment Programme UNEP | Zinck J.A.,International Institute for Geo information Science and Earth Observation ITC
Journal of Environmental Quality | Year: 2010

Wind-driven land degradation negatively impacts on rangeland production and infrastructure in the Valdes Peninsula, northeastern Patagonia. Th e Valdes Peninsula has the most noticeable dunefields of the Patagonian drylands. Wind erosion has been assessed at different scales in this region, but often with limited data. In general, terrain features caused by wind activity are better discriminated by active microwaves than by sensors operating in the visible and infrared regions of the electromagnetic spectrum. Th is paper aims to analyze wind-driven land degradation processes that control the radar backscatter observed in different sources of radar imagery. We used subsets derived from SIR-C, ERS-1 and 2, ENVISAT ASAR, RADARSAT-1, and ALOS PALSAR data. Th e visibility of aeolian features on radar images is mostly a function of wavelength, polarization, and incidence angle. Stabilized sand deposits are clearly observed in radar images, with defined edges but also signals of ongoing wind erosion. One of the most conspicuous features corresponds to old track sand dunes, a mixture of active and inactive barchanoid ridges and parabolic dunes. Th is is a clear example of deactivation of migrating dunes under the influence of vegetation. Th e L-band data reveal details of these sand ridges, whereas the C-band data only allow detecting a few of the larger tracks. Th e results of this study enable us to make recommendations about the utility of some radar sensor configurations for wind-driven land degradation reconnaissance in mid-latitude regions. Copyright © 2010 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved. Source

Discover hidden collaborations