Hydrogeochemical Characteristics of Groundwater in the Bassit Ophiolitic Area, Northwestern Syria

Abstract

In order to evaluate the hydrogeochemical properties and the quality of groundwater in the Bassit ophiolitic area (Northwestern Syria), 27 groundwater samples were collected from springs and wells during dry and wet seasons. Physical-chemical parameters and heavy metal concentrations of groundwater samples were measured. The analytical results showed that the groundwater is very hard and slightly alkaline in nature. The concentrations of major ions are in the following order: Mg2+ > Ca2+ > Na+ > K+ and HCO32- > Cl- > SO42- > NO3-. The magnesium ion (Mg2+) has exceeded the permissible limit for drinking purpose, reflecting an influence of ophiolitic rocks on the local groundwater chemistry. The hydrogeochemical facies are mainly (Mg-HCO3) and (Mg/Ca-HCO3) types with a minor occurrence of Ca-HCO3 type. According to Gibbs diagrams, all samples fall in the rock dominance field and the chemical quality of groundwater is related to the lithology of the area. The maximum concentrations of some heavy metals in groundwater samples for two seasons are relatively low (16.9 μg/l Cr, 19.27 μg/l Ni, and 1.78 μg/l Co), which are under the permissible limit for a drinking purpose. Also to evaluate the groundwater suitability for irrigation purposes, Salinity hazard (EC), Sodium hazard (SAR, Na%) and magnesium hazard (MAR) were appraised. It is found that 89% of groundwater samples in two seasons were mainly classified as high salinity/low sodium, which suggests that this groundwater is unsuitable for irrigation. Only (11%) of samples were classified as medium salinity/low sodium and as such suitable for irrigation. The magnesium hazard showed that 82% of the samples had high values (MAR > 50%) and as such unsuitable for irrigation. Soil irrigated with such groundwater will not be exposed to any alkali hazard, but will suffer from salinity and magnesium hazard.