Some aspects of heavy metals contamination remediation and role of biosurfactants

Contamination by heavy metals is the result of different industrial activities. The presence of heavy metals in soil and water causes serious problems, as these materials are not biodegradable and do contaminate both biological systems and the subsoil. Biological surface-active compounds otherwise known as biosurfactants in general and rhamnolipids biosurfactants in particular have been successfully employed in the remediation of environments contaminated with heavy metal ions. The aim of the present review is to highlight potential applications of these tensioactive compounds for use in environmental heavy metals removal and bioremediation and processes involved.     

Linking agricultural adaptation strategies,food security and vulnerability: evidence from West Africa

Adaptation strategies to reduce smallholder farmers’ vulnerability to climate variability and seasonality are needed given the frequency of extreme weather events predicted to increase during the next decades in sub-Saharan Africa, particularly in West Africa. We explored the linkages between selected agricultural adaptation strategies (crop diversity, soil and water conservation, trees on farm, small ruminants, improved crop varieties, fertilizers), food security, farm household characteristics and farm productivity in three contrasting agro-ecological sites in West Africa (Burkina Faso, Ghana and Senegal). Differences in land area per capita and land productivity largely explained the variation in food security across sites. Based on land size and market orientation, four household types were distinguished (subsistence, diversified, extensive, intensified), with contrasting levels of food security and agricultural adaptation strategies. Income increased steadily with land size, and both income and land productivity increased with degree of market orientation. The adoption of agricultural adaptation strategies was widespread, although the intensity of practice varied across household types. Adaptation strategies improve the food security status of some households, but not all. Some strategies had a significant positive impact on land productivity, while others reduced vulnerability resulting in a more stable cash flow throughout the year. Our results show that for different household types, different adaptation strategies may be ‘climate-smart’. The typology developed in this study gives a good entry point to analyse which practices should be targeted to which type of smallholder farmers, and quantifies the effect of adaptation options on household food security. Subsequently, it will be crucial to empower farmers to access, test and modify these adaptation options, if they were to achieve higher levels of food security.     

Adaptation of agriculture to climate change in semi-arid Borena,Ethiopia

Livestock production is very risky due to climate variability in semi-arid Sub-Saharan Africa. Using data collected from 400 households in the Borena zone of the Oromia Region, we explored what drives adoption of agricultural practices that can decrease the vulnerability of agro-pastoralists to climate change. Households with more adaptive capacity adopted a larger number of practices. The households’ adaptive capacity was stronger when the quality of local institutions was high. However, adaptive capacity had less explanatory power in explaining adoption of adaptation options than household socio-economic characteristics, suggesting that aggregating information into one indicator of adaptive capacity for site-specific studies may not help to explain the adoption behaviour of households. Strong local institutions lead to changes in key household-level characteristics (like membership to community groups, years lived in a village, access to credit, financial savings and crop income) which positively affect adoption of agricultural practices. In addition, better local institutions were also positively related to adoption of livestock-related adaptation practices. Poor access to a tarmac road was positively related to intensification and diversification of crop production, whereas it was negatively related to the intensification of livestock production, an important activity for generating cash in the region. Our findings suggest that better local institutions lead to changes in household characteristics, which positively affect adoption of adaptation practices, suggesting that policies should aim to strengthen local institutions.     

Geochemical characterization and health risk assessment in two diversified environmental settings (Southern Italy)

Environmental Geochemistry and Health - An integrated approach using chemical and microbial indicators has been tested in two different sites of the Campania Plain (Southern Italy) with different...     

Geostatistical analysis of densities of Liocarcinus depurator (Brachyura: Portunidae) on the western Mediterranean from 1994 to 2003

Bottom trawl estimates of densities of the portunid crab Liocarcinus depurator along the Mediterranean coast of Spain from 1994 to 2003, covering a depth range of 50–800 m, were analysed using non-linear geostatistical techniques. The variation of the spatial distribution was modelled through variogram analysis using depth as a covariate. Patch size ranged from 20 to 75 km. Crab density showed a general decrease from 1994 to 2003. L. depurator high-density areas were characterised as either occasional or permanent (always present every year). High-density patches appeared to be associated with either upwelling or strong river influence, i.e. the Western Alborán Sea and the Ebro Delta. The application of non-linear geostatistical techniques proved useful in identifying permanent high-density population patches, thereby highlighting regions of special interest for the ecology of the species.     

Deep carbon degassing in the Matese massif chain (Southern Italy) inferred by geochemical and isotopic data

Environmental Science and Pollution Research - The Italian Apennines are among the most important sources of freshwater for several Italian regions. With evidences of deep CO2-rich fluids intruding...