ENVIRONMENTAL RISK ASSESSMENT OF MERCURY AND ARSENIC IN SOME SOILS - AL BAHARIYA OASIS – EGYPT

Occurrence and assessment of the environmental risk of mercury and arsenic in Al Bahariya Oasis have not been given due attention although it has diverse agricultural areas. This study was carried to assess the environmental danger of mercury and arsenic in agricultural soils in the northern part of Oasis, near the mining area. Sixty-four (0-30 cm) soil samples and thirty-two plant samples were collected from four locations; EL Harra (A1), Mendisha (A2), Al Kaser (A3), and Al Bawiti (A4). Samples were analyzed for mercury and arsenic in all soil samples and their fractionations were determined. Indices of contamination factor (Cf), enrichment factors (EFs), potential ecological risk (PER), and Geoaccumulation index (Igeo) were calculated to evaluate the level of pollution. Results showed high content of Hg and as than the background level and WHO limit in soil and plants. Based on Igeo and ER value, soils were strongly polluted and had very high ecological risk in case of mercury. Soils were moderately contaminated and had moderate ecological risk in case of As. According to CF and EF soil had very high contamination factor and was considered extremely polluted by Hg, while it had a significant degree of contamination and significant level of enrichment by As. Fractions distribution showed that carbonate-bound and exchangeable fractions were the predominant fraction of elements, which interoperated absorption of these elements by plants. Anthropogenic activities might be the most responsible source of contamination especially mining activities, Hence, Pollution must be controlled in this area