ASSESSMENT OF GROUNDWATER QUALITY IN SIRTE CITY

Abstract

Wadi Jarif in sirte area Libya, is located between longitude 16º 12` 00" E to 16º 23' 00" E and latitude 31º 12` 00" N to 30º 59` 00" N. The length of this valley is approximately (31 km) which stream tube tightens at the heights of the valley and increases in width at the bottom of the valley. It is characterized by the dominance of typical continental arid and semi-arid features with little rainfall, hot and dry weather in summer and cold and rainy in winter, Wadi Jarif area is selected for this study, because the hydrological, hydrogeological and environmental studies in the area are very restricted in some studies that described the area generally. Also, due to its large shortage in good quality water resources. Thirty groundwater samples were collected from Wadi Jarif. The collected samples were subjected to different analyses in order to conduct hydrochemical and bacteriological studies of the study area. The available groundwater water resources quality are assessed .their suitability for different uses are defined. The physicochemical parameters of the studied groundwater samples revealed that groundwater of Wadi Jarif are mainly slightly alkaline where the pH ranges from 7.03 to 7.60 (average7.19), excessively mineralized water and brackish to saline water. The recorded temperature of the studied groundwater of Wadi Jarif sample are fluctuated from 28 to 75 oC (average 41 oC). The total dissolved salts (TDS) ranges from 3311 to 8187 mg/L (average 5806 mg/L). Most of the studied groundwater samples have electrical conductivity (EC) values ranges from 5241 to 13150 µS/cm (average 8183 µS/cm). From the foregoing discussion, the physicochemical parameters of the studied groundwater samples revealed that groundwater of Wadi Jarif are mainly slightly alkaline, excessively mineralized water and brackish to salt water. The order of abundance of the major ions in the groundwater of Wadi Jarif are Na+ > Ca2+ > Mg2+ > K+. The anions relationship are Cl- > SO42- > HCO3- > NO3-. The major ions concentrations show an observed decrease away from the sea coast with exception for K+ and HCO3-. This distribution may be related impact of sea water intrusion. The trace metals concentration such as (Ba) in the studied groundwater of Wadi Jarif ranges from 0.02 to 0.2 ppm (average 0.05 ppm). The concentrations of (Mn) are fluctuated from 0.01 to 0.30 ppm (average 0.08 ppm). The concentrations of (Si) are fluctuated from 0.82 to 3.13 ppm (average 2.14 ppm). The concentrations of (Sr) are fluctuated from 0.01 to 0.3 ppm (average 0.04 ppm). Among different bacteriological parameters measured in the studied groundwater of Wadi Jarif, the fecal coliform bacteria form from 10 wells isolated from the studied groundwater samples of Wadi Jarif are ranged from 20 to 140 CFU/100 mL. The total count of E. coli form ranged from 40 to 2400 CFU/100 mL. The Fecal Streptococci form per 100 mL ranged from 20 to 500 CFU/mL. which revealed that this groundwater is classified