THE QUALITY OF GROUNDWATER IN BAHRAIN

The quality of groundwater and house tap water throughout the State of Bahrain has been investigated with respect to pH, salinity, conductivity, bicarbonate, chloride, sulfate, sodium, potassium, magnesium, calcium, nitrite, nitrate, ammonia and phosphate. Groundwater showed elevated levels for salinity, chloride, sulfate, sodium and magnesium, with ranges of 1.40-9.30 ppt, and 110-4407, 239-1385, 247-2165, and 36-313 mg l-1, respectively. These values increased from western Bahrain reaching maximum values along the southeastern coastal zone. Nitrate concentration ranged from 1.3 to 23.3 mg l-1 with an average value of 4.4 mg l-1. The results of the study indicate deterioration of groundwater in localized areas. In the case of tap water, the observed ranges for salinity, chloride and sodium were 0.7-1.5 ppt, and 280-750 and 140-400 mg l-1, respectively. The quality of tap water was assessed by comparing values with WHO guidelines.