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Journal of Environmental Hydrology
ISSN 1058-3912 |
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Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 15 (2007), Paper 8 Posted March 18, 2007 EFFECTS OF CESSPOOL SYSTEMS ON GROUNDWATER QUALITY OF SHALLOW BEDROCK AQUIFERS IN THE RECHARGE AREA OF WADI FATIMAH, WESTERN ARABIAN SHIELD, SAUDI ARABIA
Mahmoud Said Alyamani
ABSTRACT An investigation of the potential contamination of groundwater from on-site domestic wastewater systems blasted in weathered and fractured bedrock in the upper reaches of Wadi Fatimah basin, western Saudi Arabia, was conducted during April, 2005. Impacts of on-site systems on the shallow aquifer are shown by the elevated concentrations of nitrate and chloride. The chemical analyses results of the groundwater samples, collected from private domestic wells in a residential site, show that the nitrate concentration in groundwater exceeded the maximum contaminant level of 45 mg/l. It ranges from 151 to 556 mg/l with an average of about 236 mg/l which is greater than the average background (16.3 mg/l) of the nitrate concentration in the undeveloped region within the wadi basin. The high nitrate content is a widespread pollutant that is a serious threat to public health. Nitrate contamination is generally observed in close proximity to potential point waste sources. The dominant groundwater movement in the area is the major factor contributing to the groundwater deterioration by nitrate that has leached from on-site wastewater disposal systems. The chloride-nitrate relationship has been used to differentiate the potential sources of chloride. No faecal coliforms were detected in the groundwater samples, even in samples with the highest nitrate concentrations, suggesting that residence time in fractured and weathered bed rocks was sufficient for bacterial die-off. Reference: Alyamani, M.S. 2007. Effects of cesspool systems on groundwater quality of shallow bedrock aquifers in the recharge area of Wadi Fatimah, western Arabian Shield, Saudi Arabia. Journal of Environmental Hydrology, Vol. 15, Paper 8. CONTACT: Faculty of Earth Sciences Hydrogeology Department P.O Box 80206 Jeddah 21589, Saudi Arabia E-mail: malyamani@kau.edu.sa |
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