Selenium Geo-Availability in Stream Sediments in Selected Communities in the Kintampo Area of the Bono East Region of Ghana

Abstract

Selenium is a necessary trace element naturally found in rocks, soil, water and some food crops that contributes to human development. Due to its role in maintaining normal functions of the human body and the health problems associated with its deficiency and toxicity, it is referred to as the 'double-edged sword element'. A total of 43 stream sediment samples were collected using a Global Positioning System receiver to navigate predetermined locations. Selenium concentration in the samples was assessed using inductively coupled plasma/optical mass spectrometry technique and pH measured with a pH meter. The pollution status of Selenium was determined by calculating the degree of contamination, pollution load and geo-accumulation indices. Stream sediments were underlain by sedimentary rocks with lithologies such as sandstone, mudstone, shale and phyllite. Out of the 43 samples analyzed, 35 (81%) were deficient in selenium. Selenium levels ranged from < 0.2 mg/kg to 0.4 mg/kg with a geometric mean of 0.11 mg/kg reflecting the global background value in sedimentary rocks. The study found almost the entire area to be deficient in selenium. The low selenium geo-availability may adversely affect its bioavailability in food crops with profound public health implications for inhabitants of the study area who derive dietary selenium through the consumption of these crops. Consequently, our findings call for further research into the link between Se content of food crops grown in the study context, human blood selenium levels and health outcomes in the population to facilitate the potential implementation of remedial public health interventions.