Measurement of the Organic and Inorganic Pollutants in Langroud River

Due to increasing water withdrawal from Langroud river for industrial and agricultural purposes, the rate of its pollution has been investigated. Samples have been collected from 6 different stations during the four seasons of year and concentration of organic pollutants such as PAHs and pesticides have been measured using an HPLC system. Concentration of metallic elements have also been measured using A.A.S. Physical and chemical parameters such as BOD, COD, Phosphate, Nitrate, Nirtite, Total. hardness, Salinity, Temperature. and pH have been quantitatively analyzed. The measured levels of pollutant concentration during four seasons have been compared.Concentration of PAHs was in the range 0.005-20.28µg/L that exceeds from recommended standard level of 0.002-0.05µg/L. Pesticide is decomposed when exposed to high temperature, or direct sunlight, therefore pesticides concentrations were below HPLC detection limit, and were not substantial. The mean concentrations (mg/L) for elements and ions were found to be: Fe (0.150), Cu(0.004), Mn(0.154), Zn(0.008), Al(0.078), Cd(0.000), K(6.947), Ba(0.151), Sr(1.125), Na(200.00), Cl-(366.00), NO3-(0.973), No2-(0.420), PO43-(0.418). The observed high concentration of salinity and minerals found during summer time in the river is due to the decreased rate of rainfall as well as seawater intrusion.The high levels of BOD (1.1-2mg/L) and COD (5-143.5mg/L) shows that the water is potentially polluted due to high discharge rate of domestic and industrial wastewater.