Abstract
Heavy metals in the subsurface may result in a significant potential health hazards. Heavy metals are also known to interact with the essential trace minerals at the level of absorption and metabolism. Measurements of heavy metals in drinking water have been widely investigated. However, measurements of heavy metals in soil and plant samples in Najran area, KSA have not been studied yet. Therefore, we are aiming to study the heavy metals levels in soil and plant samples as well as their compatibility with national and international guidelines. Five heavy metals namely; Cd, Cu, Fe, Zn and Pb, were successfully determined by atomic absorption spectroscopy in soil and plant samples in Najran area, KSA. Soil and plant samples were collected from four gardens within Najran area. The results indicated that Cadmium was not detected in all soil and plant samples. The results showed that the mean concentrations of metals in soils, ranging from 21.4 ppm to 1279.7 ppm, were found to be lower than the maximum allowable limits in soil as compared to many countries and WHO. Also, the mean concentration of heavy metals in plant, ranged from 4.06 ppm to 149.4 ppm, were found to be lower than the maximum allowable limits in plants as compared to WHO/FAO. Moreover, the results indicated that the metals concentrations in plant were lower than that in soil. Furthermore, enrichment Factor (EF) of heavy metals in soil showed that Pb (EF = 7.95) had significant enrichment. The low values of EF data indicated that the heavy metals probably originated from natural source. The results of Geo-accumulation Index (I-geo) of heavy metals in soil showed that the soil is moderately to strongly polluted.with Pb (I-geo= 2.37). This study will contribute to the screening of heavy metal pollution in soil and plants of Najran area.