Nitrates in the under-ground sheets waters of the north of Tunisia

Abstract

Nitrates were evaluated in under-ground sheets waters of the north of Tunisia during the years 2003, 2004, 2006, 2007 and 2008. The results obtained showed that all sheets are contaminated by nitrates. High concen-trations beyond often 100 mg/l and reaching more than 300 mg/l were determinated in the water of most sheets studied. The sheets that are more contaminated, are located in Bizerte, Nabeul, Ben Arous and Ariana areas which are known by a high urbanization and important industrial and agricultural activities. The evolution of nitrates during last years showed unstable levels caused probably by seasonal and accidental contaminations. The high nitrates contents established are probably the result of environment pollution by industrial and municipal wastes and by excessive use in agricul-ture of chemical and natural fertilizers. Preventive measures must be led in order to decrease the nitrates levels in under-ground waters and to protect it from pollution.