An evaluation of waste and well water quality for agriculture production around Erbil city, Iraq

Abstract

Erbil city is located in the northern Iraq with a population of over one million people. Due to water crises farmers usually use wastewater and well water for the agricultural production. In this study six stations were designed to sample waste water and three from well water to define waste water and ground water characteristics. In this study, Residual Na+ Carbonate, Mg++ hazard, salinity hazard, Kelley index, %sodium, total hardness, permeability index, potential salinity, sodium adsorption ratio, and Irrigation Water Quality Index (IWQI) were determined. The order of average cation concentrations in water was Mg2+> Ca2+ > Na+ > K+. While the proportion of main anions in water were HCO3 >SO4 > Cl. The highest concentrations of Ca2+, Mg2+ and Na+ were found in well water, while the highest concentration of K+ was found in wastewater. The maximum concentration of HCO3 and Cl recorded in well water, while the highest concentration SO4 recorded in wastewater. Moreover, the order of trace elements was Pb > Al > Fe > Cd > As > Mn >Cr > Ag > Ni. Keeping in mind metal concentration set by  US EPA and FAO (1999) and (1994) guidelines the levels of Pb, Al, Fe, Mn, Cr, Ag and Ni in the waste and well water were within the admissible limitations  for irrigation schemes. Moreover, limitations of As and Cd were beyond permissible limitation need to be reduced.  The IWQI ranged from 88.92 to 95.09 in the waste water samples. Overall assessment reveals that cultivated agriculture plants were secured from toxic compounds.