Development and evaluation of the drinking water quality index in the Eastern Bank of Nineveh Governorate

Abstract

Groundwater quality is the result of all the chemical and hydrological reactions and processes that affected on the water. The Water Quality Index (WQI) is a mathematical tool that describes water quality to assess the levels of water usage. This study attempts to develop a new method for the groundwater quality index (GWQI). It is based on the standards of the (WHO, 2006) and the (IQS 417, 2001) to assess the groundwater and validity of wells water for drinking in the eastern bank of Nineveh Governorate. 139 well water samples were taken to measure 12 physical variables (pH, E.C. and T.D.S.) and chemical variables (Ca²⁺, Mg²⁺, Na⁺, K⁺, SO₄², HCO₃^2-, Cl^-, NO₃^-, and T.H.). Nine variables were use to calculate the WQI, excluding non-influential parameters (potassium, pH, and bicarbonate) that fall within the permissible ranges for drinking in WHO and IQS 417, based on the statistical treatments. The study developed and modified equations and classifications were used to reflect an accurate quality of the groundwater in the region. The (GWQI.3) classified depending on (WHO, 2006), 37% of wells were unsuitable, 57% were very poor, 6% were poor, while the (GWQI.6) was classified as follows: 68% are unsuitable, 30% very poor, 2% poor, depending on (IQS 417, 2001). In general, groundwater in the study area is unsuitable for drinking and civil uses.