Trends in water quality of some wells in Saudi Arabia, 1984-1989.

A survey of the quality of 4255 well samples collected from 1062 wells in the period 1984 through 1988, 388 samples collected in 1989, and 319 tank water samples distributed to houses, has been conducted throughout the Kingdom of Saudi Arabia. Sampling included seven regions in Saudi Arabia and analyzed for total dissolved salts, nitrate, nitrite, ammonium and faecal coliforms. The data generally showed a progressive improvement in the quality of well samples during the period under investigation. However, there are still a significant number of water samples showing high levels of pollutants. Nitrate levels of > 45 mg l-1 were observed in 8% of the well samples in 1989 and 5% of them showed the presence of both elevated levels of nitrate and faecal coliforms. Five percent of the well samples in 1989 contained high levels of nitrate, ammonium and faecal coliform. It is concluded that human and animal wastes are the primary continuous source of pollution in the well water samples tested.