Application of EDXRF in the Determination of the Abundance and Distribution of Arsenic along a Federal Highway in Northern Nigeria

Abstract

The transmission-emission technique of EDXRF was used to determine the abundance and distribution of Arsenic in soil along a Federal Highway in northern Nigeria. Depth profile of the element was investigated. Subsequently, top soils within a depth of 5 cm were collected along parallel and perpendicular transects and analyzed for arsenic. Samples were crushed and ground into fine, near-homogenous particle-sized powder and pelletized for irradiation and counting. Preliminary investigation revealed that within the depth considered, the concentration of arsenic was decreasing and increasing with increasing depth. The minimum level of arsenic of 17.7 mg/L was detected in the study area at a distance of 100 m from the road, while the maximum level of 110 mg/L was detected by the roadside; and the mean concentration of the element ranged 21.6 – 101.9 mg/L with a background loading factor (BLF) of between 1.1 and 5.0 which is suggestive of an environmental pollution. The data indicated initial decrease in arsenic concentration; however this pattern was reversed with increase in distance from the road. These data, in addition to that of the depth profile were clear indications that the observed arsenic concentrations were not due to vehicular emissions, rather, they have geochemical significance.