Quality Assessment of Groundwater of Almadinah Almunawarah City

Renewable water resources in Saudi Arabia are limited with groundwater as the major source for water supply. This study was conducted to assess the quality of groundwater in Almadinah Almunawarah, Saudi Arabia. Water samples were collected from 60 wells in 2010. Physical and chemical parameters were examined. The results of colour, turbidity, odour, pH, and nitrite in all samples were below the local water guideline values. The fluoride concentrations in 8% of the samples were higher than the guideline value. The taste in 87% of the samples was unacceptable. Intolerable levels of both total hardness and TDS were found in most of the samples (~ 83%). Nitrate levels were above the guideline value in 65% of sample. Most of the samples (80–87%) have failed the guidelines for sodium, chloride, and sulphate. On the other hand, none of the samples was found to contain Cr, Ni, Cu, Zn, Cd, Ba, and Pb exceeding the guideline values. However, 5% of the samples have arsenic concentrations over the limit (results 12.0–29.0 µg L-1). Similarly, 5% of the samples have iron concentrations (320–589 µg L-1) in excess of the guideline value. The level of manganese in only one sample (183 µg L-1) was greater than the guideline value and 10% of the samples have magnesium (range 159000–210000 µg L-1) above the limit. Although the water of the investigated wells does not satisfy many of the general drinking water guidelines due to the local environment and climate, most of the samples are in compliance with the guideline values for metals in drinking and irrigation water.