Marine dredged sediments as new materials resource for road construction

Large volumes of sediments are dredged each year in Europe in order to maintain harbour activities. With the new European Union directives, harbour managers are encouraged to find environmentally sound solutions for these materials. This paper investigates the potential uses of Dunkirk marine dredged sediment as a new material resource for road building. The mineralogical composition of sediments is evaluated using X-ray diffraction and microscopy analysis. Since sediments contain a high amount of water, a dewatering treatment has been used. Different suitable mixtures, checking specific geotechnical criteria as required in French standards, are identified. The mixtures are then optimized for an economical reuse. The mechanical tests conducted on these mixtures are compaction, bearing capacity, compression and tensile tests. The experimental results show the feasibility of the beneficial use of Dunkirk marine dredged sand and sediments as a new material for the construction of foundation and base layers for roads. Further research is now needed to prove the resistance of this new material to various environmental impacts (e.g., frost damage).     

Proximal exposure of public schools and students to major roadways: a nationwide US survey

This study addresses the effect of urban planning and road development on the health risk of students attending schools near major roadways. The proximity of public schools and students was quantified to Interstate, US and state highways in nine large Metropolitan Statistical Areas (MSA) of the USA. In total among the surveyed schools and students, over 30% fell within 400 m of a major roadway and over 10% were within 100 m. For some MSAs almost half of the student population attended schools near (≤400m) major roadways, resulting in a potentially increased risk for asthma and other chronic respiratory problems, especially in schools representing the urban fringe locale. It was concluded that proximity of major roadways should be an important factor in considering sites for new schools and developing policies for reducing the exposure in existing schools. The findings provide an important reference point for coordinating future urban development, transportation and environmental policies.     

Pesticide residues in sediments and aquatic species in Lake Nokoué and Cotonou Lagoon in the Republic of Bénin

Lake Nokoué and Cotonou Lagoon are the most important and most productive continental freshwaters in Bénin, with an estimated fish production of over 2 tonnes per hectare in Lake Nokoué. Organochlorine pesticides are used in agriculture and to repel tsetse flies, malaria mosquitoes and other diseases raised. Sediment, fish, shrimp and oyster species were collected in Lake Nokoué and Cotonou Lagoon for pesticide residues analysis. The main pesticides identified in sediment were pp′-DDT and its metabolites pp-DDE and pp′-DDD, with residue levels between the detection limit and 24.4 μg/kg dry weight. Fish species commonly consumed such as Elops lacerta, Podamasys jubelini, Gobbienellus occidentalis, Ethmalosa fimbriata, Mugil cephalus and Hemichromis fasciatus were contaminated with residues of seven to nine pesticides, including pp-DDE, op′-DDD, pp′-DDD, op′-DDT, pp′-DDT, α-endosulfan, aldrin, dieldrin and γ-hexachlorocyclohexane. The levels ranged from detection limit to 289 ng/g lipid. The same pesticides were also detected in other aquatic species, such as shrimp and oysters. A summed risk assessment, comparing pesticide intake levels through fish consumption with tolerable daily intake levels proposed by the World Health Organization, showed in all cases a low risk for human health.     

Environmental Modeling and Methods for Estimation of the Global Health Impacts of Air Pollution

Air pollution is increasingly recognized as a significant contributor to global health outcomes. A methodological framework for evaluating the global health-related outcomes of outdoor and indoor (household) air pollution is presented and validated for the year 2005. Ambient concentrations of PM2.5 are estimated with a combination of energy and atmospheric models, with detailed representation of urban and rural spatial exposures. Populations dependent on solid fuels are established with household survey data. Health impacts for outdoor and household air pollution are independently calculated using the fractions of disease that can be attributed to ambient air pollution exposure and solid fuel use. Estimated ambient pollution concentrations indicate that more than 80% of the population exceeds the WHO Air Quality Guidelines in 2005. In addition, 3.26?billion people were found to use solid fuel for cooking in three regions of Sub Saharan Africa, South Asia and Pacific Asia in 2005. Outdoor air pollution results in 2.7?million deaths or 23?million disability adjusted life years (DALYs) while household air pollution from solid fuel use and related indoor smoke results in 2.1?million deaths or 41.6?million DALYs. The higher morbidity from household air pollution can be attributed to children below the age of 5 in Sub Saharan Africa and South Asia. The burden of disease from air pollution is found to be significant, thus indicating the importance of policy interventions.     

Climate sensitivity,agricultural productivity and the social cost of carbon in FUND

Environmental Economics and Policy Studies - We explore the implications of recent empirical findings about CO2 fertilization and climate sensitivity on the social cost of carbon (SCC) in the FUND...     

Horizon scanning for South African biodiversity: A need for social engagement as well as science

Ambio - A horizon scan was conducted to identify emerging and intensifying issues for biodiversity conservation in South Africa over the next 5–10 years. South African biodiversity...     

Occupational exposure to pesticides and associated health effects among greenhouse farm workers

Environmental Science and Pollution Research - The number and production capacities of greenhouse farms have been increased across the globe, driven by an effort for addressing food security...     

Forecasting Alpine Vegetation Change Using Repeat Sampling and a Novel Modeling Approach

Global change affects alpine ecosystems by, among many effects, by altering plant distributions and community composition. However, forecasting alpine vegetation change is challenged by a scarcity of studies observing change in fixed plots spanning decadal-time scales. We present in this article a probabilistic modeling approach that forecasts vegetation change on Niwot Ridge, CO using plant abundance data collected from marked plots established in 1971 and resampled in 1991 and 2001. Assuming future change can be inferred from past change, we extrapolate change for 100 years from 1971 and correlate trends for each plant community with time series environmental data (1971–2001). Models predict a decreased extent of Snowbed vegetation and an increased extent of Shrub Tundra by 2071. Mean annual maximum temperature and nitrogen deposition were the primary a posteriori correlates of plant community change. This modeling effort is useful for generating hypotheses of future vegetation change that can be tested with future sampling efforts.     

Researching Visual Representations of Climate Change

This paper responds to calls for greater clarity about the application of theory and method in research on mediated communication about climate-change. Specifically, it identifies conceptual and methodological challenges for researching visual representations of climate change. We suggest current research is impeded by a lack of methodological explication and an unclear relationship between theories of visual meaning and the application of social science methods such as content analysis and frame analysis. As a first step towards addressing these issues, we review existing research to identify the methodological procedures that require explication in order to support the replication of studies and the comparison of findings. We then draw on the seminal work of Roland Barthes to examine how theories of visual meaning may be integrated into social-scientific research methods. Specifically, we demonstrate how Barthes’ concepts of denotation, connotation and mythology may be related to research concerns about the selection of visual content, the classification of image frames, audience responses, and analyses of ideological meaning. The conclusion highlights further possibilities for developing a robust form of visual analysis that meets the standards of social scientific research while addressing the fundamental insights about visual meaning derived from cultural theories of meaning.