Levels of Selenium in Vegetables, Medicinal Plants and Soils from Selected Sites within the Lower Benue River Basin Development Authority Catchment, Nigeria

Abstract

The levels of Selenium (Se) in vegetables, medicinal plants and soils from selected sites within the Lower Benue River Basin Development Authority catchment (spanning latitudes 6o 15’ and 9o 10’N and longitudes 6o 22’ and 10o 25’E) were determined as part of investigations of the element’s biogeochemistry in the area. Seventy eight (78) plant and forty (40) agricultural soil samples were obtained from eight sites in the study area and their levels of Se determined using the simple, sensitive and selective 2, 4-DNPH-NEDA spectrophotometric method. Results obtained showed soil Se in the whole area was in the range 1.0 x 10 -4 – 97.0 x 10 -4 mg/kg, with an average of 44.0 x 10 -4 ±0.0020 mg/kg, while the mean Se levels in vegetables and medicinal plants were 217.0 x 10 -4 ±0.0105 mg/kg and 206.0 x 10 -4 ±0.01 mg/kg respectively. These results show that Se in the soils and vegetation in the area is lower compared to literature reports. The Lower Benue Valley (LBV; coordinates of longitudes 7°00'E and 8°30'E and latitudes 5°00'N and 6°30'N) in Nigeria where HIV/AIDS prevalence is historically fairly high and considering the role of Se in the progression of this disease we embarked on studies of the phytopedochemical distribution of the element in the areas including LBV.