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The purpose of this paper is to examine the presence of geogenic contaminants in groundwater from shallow aquifers of the crystalline basement complex rocks of Ibadan south-western, Nigeria.

A total of 30 drinking water samples, (six samples each from the five major lithologic formations of the study area) were collected from hand dug wells during the rainy season. Atomic absorption spectrophotometry was used to determine concentrations of arsenic, iron and fluoride in drinking water samples and also concentrations of other chemical parameters that could affect the concentrations of the geogenic contaminants including pH, Ca, Mg, Na and SO₄2−. Descriptive statistics, multiple correlation and analysis of variance were used to examine the relationship between the geogenic contaminants and concentration of other chemical parameters while inverse distance weighting was used to produce risk maps.

The results showed Arsenic concentration exceeding the WHO recommended concentration for drinking water in all the samples within the area. Samples from 16.6 per cent of the wells exceeded the recommended limit for fluoride while iron was present in most of the samples within acceptable limits. The study also revealed no significant difference in concentration of contaminants between the geologic formations.

Geogenic contamination has been scarcely studied in Nigeria. This research, therefore, is a paradigm shift in the study of groundwater contamination which had been mainly focused on anthropogenic contaminants. The outcome of this research will engender policy makers and researchers to pay more attention to geogenic contamination than anthropogenic contaminants in Nigeria.

The study investigated the heavy metal flux around the vicinity of a steel recycling factory using passive biomonitoring technique with several pollution indices to assess the quality of the ambient environment.

The vegetation around the facility was identified, and the most abundant species were selected for analysis. The collected samples were dried, milled, sieved and analyzed for elemental composition using energy dispersive X-ray fluorescence (ED-XRF). Pollution indices were used to quantitatively assess the data.

Results show that maximum contamination occurs at the vicinity of factory. Generally, the deterioration of the ambient air around the vicinity of the steel recycling plant decreases with increasing distance from the steel recycling plant. However, for the radius considered in this study – 1 km, the ambient air at 1 km of the steel recycling facility is quickly deteriorating, and there is an urgent need for measures to mitigate the air quality impact of the steel recycling facility.

The study shows that the metal recycling process emits high levels of heavy metals to the environment, and there is an urgent need for personal protective equipment for the human population working in and around the close proximity of the recycling plant.

Southeast Asia has been actively undergoing land conversion into agricultural lands over past few decades. This creates the challenges to the nation in dealing with the non-point source pollutants in many fluvial systems, thus requiring an effective approach in sediment source apportionment for an appropriate target mitigation procedure. The trace element property from different source points was used for catchment classification of Galas River. Sediment sample collection was carried out at the sources and sink areas of the catchment system. Fine sediment was analysed using X-ray fluorescence to obtain elemental composition followed by the statistical test and numerical model. Out of 83 elements, 12 elements (Mn, Ca, Cr, Ga, Dy Hf, Y, V, Th, Pb, Zn and Sr) have been selected as best tracer signatures. The solver model has indicated Pergau River as the major sediment contributor to this large catchment system. The model output could directly be proportional with the land-use practice, indicating excessive terrestrial alteration has taken place within the sites for agricultural plantation purposes. Thus, this highly recommends for the decision-making use to the targeted areas to overcome the serious sedimentation issues caused by the tillage operation in affected stream points and to improve the watershed quality.