Effects of artisanal gold mining activities on soil properties in a part of southwestern Nigeria

The study examined some physical and chemical characteristics of soils in an unmonitored mining community in southwestern Nigeria. This study aimed at determining if the active (recently mined), abandoned mines, adjacent farmland, and a relatively less-disturbed forest re-growth region in the community exhibit significantly different or similar characteristics. The main hypothesis is that sites of artisanal gold mining activities are characterized by higher concentrations of toxic metals than the farmland and forest sites. A 25 by 25 meters plot was demarcated in each sample area and soil samples were obtained from 0 to 15 cm soil layer (at 5 by 5 m subplot level). Soil samples were analyzed for particle size distribution, pH, organic C, total N, available P, exchangeable Ca2+, Mg2+, K+, and Na+, total acidity, and selected heavy metals (Zn, Hg, Cu, Mn, Cd, Pb, and Fe). The study showed that soils at the active and abandoned mine sites were more of sandy particles, and contained significantly higher concentrations of heavy metals but lesser concentrations of soil nutrients than the farmlands and the relatively undisturbed areas in the study area. The study concluded that artisanal gold mining activities caused severe soil degradation and loss of important soil nutrients in the area. The impact of the mining activities is a major threat to qualitative food security and sustainable livelihoods in the area

Climate, Urbanization and Environmental Pollution in West Africa

The need to elucidate the urbanization–climate–pollution nexus in West African arose from the several reported, but disjointed cases of climate extremes and environmental degradation in the sub-region. This review analyzed several scenarios, to appraise the trends and relationships among the individual elements in the nexus and to ascertain the status of sustainable development in the sub-region, using the expository review methods. Urbanization was essentially characterized by population growth without complementary infrastructural development, weak coping strategies against climate extremes, numerous economic challenges, and high risk of environmental pollution. Initiative for urban renewal, urban greening and smart city development was low, and preparedness against future impact of extreme climate events and climate change is uncertain. However, there is clear evidence that the concept of sustainable development is growing in the sub-region. This is intensified by the international funding agencies insisting on the incorporation of environmental issues into development, the enactment of environmental laws and policies, and the establishment of institutions of enforcement in each country. The review concluded that although the sub-region is at the brink of severe effects of population explosion and environmental degradation, the growing awareness and implementation of the sustainable development goals may come to the rescue

An evaluation of the hysteresis in chemical concentration–discharge ( C – Q ) relationships from drained, intensively managed grasslands in southwest England

This study examined the hysteresis exhibited in concentration–discharge (C–Q) relationships in the runoff from four hydrologically separated fields (catchments) at an intensively managed grassland. The objectives were to examine C–Q relationships constructed from high-resolution time series of flow, temperature, pH, conductivity, nitrate and turbidity, and their implications for hydrological processes. High-resolution datasets from the quality assured records of the Rothamsted Research North Wyke Farm Platform in the UK were examined using a graphical method and cross-correlation statistics. The study found that storm events based C–Q hysteresis reflects the cross-correlation that is generally hidden in time series analysis of large datasets, and that although Q and water quality variables can be effectively influenced by catchment size, the C–Q relationship is less significantly influenced. The dominant C–Q relationships of the water variables in the study area reflect that saturated overland flow was prevalent during the study period in the catchments, while the CCF results indicate coupled transfer of sediments and solute in the area at lag ≥ 0