Evaluation of metals that are potentially toxic to agricultural surface soils, using statistical analysis, in northwestern Saudi Arabia

© 2015, Springer-Verlag Berlin Heidelberg. Heavy metals in agricultural soils enter the food chain when taken up by plants. The main purpose of this work is to determine metal contamination in agricultural farms in northwestern Saudi Arabia. Fifty surface soil samples were collected from agricultural areas. The study focuses on the geochemical behavior of As, Cd, Co, Cr, Cu, Hg, Pb and Zn, and determines the enrichment factor and geoaccumulation index. Multivariate statistical analysis, including principle component analysis and cluster analysis, is also applied to the acquired data. The study shows considerable variation in the concentrations of the analyzed metals in the studied soil samples. This variation in concentration is attributed to the intensity of agricultural activities and, possibly, to nearby fossil fuel combustion activities, as well as to traffic flows from highways and local roads. Multivariate analysis suggests that As, Cd, Hg and Pb are associated with anthropogenic activities, whereas Co, Cr, Cu and Zn are mainly controlled by geogenic activities. Hg and Pb show the maximum concentration in the analyzed samples as compared to the background concentration

Assessing groundwater quality of the shallow alluvial aquifer system in the Midyan Basin, northwestern Saudi Arabia

The Midyan Basin is characterized by arid climate with rare surface water flow. Groundwater is the main water resources in this region. In order to evaluate their suitability for drinking, domestic and irrigation purposes, chemical characteristics of groundwater in the Midyan Basin (northwestern Saudi Arabia) have been investigated and evaluated. A total of 72 water samples were collected from different wells and analyzed for hydrogen ion concentration, total dissolved solids, electrical conductivity, total hardness, Ca2+, Na+, Mg2+, K+, Cl-, HCO3-, NO3- and SO42-. To understand quality of groundwater and their suitability, chemical indices like sodium percentage, sodium adsorption ratio and salinity values have been calculated using analytical techniques. From traditional Piper diagram for water classification, the water quality is placed at Na+-Ca2+-SO42--Cl- type. According to the results of electrical conductivity and sodium adsorption ratio, 37% of the studied samples are regarded as highly saline, while 63% of them are classified as very highly saline. As per the Arab Gulf and international standards, such waters are not suitable for irrigation under normal condition and further action is required to remediate such problem by salinity control. Sodium content in 24% of the studied samples is regarded as high that can’t be used for irrigation purposes for any soils. Thus high level of salinity, sodium adsorption ratio and sodium percentage in most water samples have made them unsuitable.</jats:p