This study used a total of 474 groundwater samples analyzed from 2014 data to evaluate the distribution of groundwater quality in the Water and Sanitation Agency (WASA) jurisdiction of Lahore city, Pakistan. The study further assessed the variations in suitability of groundwater for drinking (emphasis on arsenic and fluoride) and irrigation using spatial correlation technique in GIS. The hydrochemical analysis revealed a predominance of Mg-Ca-HCO-SO and Ca-Mg-HCO-SO type. Distribution analysis indicated relatively higher salinity (TDS = 1667 mg/L), total hardness (TH = 558 mg/L), and alkalinity (HCO = 584 mg/L) in the south-eastern region of the city, while the central part displayed the highest levels of SO and NO. Also, the eastern region (north-south) of Lahore had significantly elevated As concentrations (up to 86 μg/L). The order of exceedance in terms of arsenic was Gunj Bakhsh town (17.4%), Nishter town (16.4%), Iqbal town (9.8%), Aziz Batti and Shalimar town (8.1%), and Ravi town (3%). The groundwater was classified as average saline to highly saline, except few samples in Aziz Batti/Shalimar town that were in non-saline group. Otherwise, the various indices classified the groundwater for irrigation as generally acceptable. With the various irrigation quality indices displaying discernible variations for the entire study area, it was observed from the distribution maps that the groundwater suitability for irrigation is relatively excellent in the areas away from industries and landfill locations. Also, the chloride analysis shows 98.7% of the groundwater samples belong to the very fresh and fresh water class. Thus, continued monitoring and studying the changes in groundwater quality in Lahore is imperative.

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More than 7 million people of Lahore city, Pakistan, use groundwater for drinking and other household purposes. The quality of drinking water from source and distribution system was investigated, and the hydrochemical characteristics and formation mechanisms of groundwater were analyzed. Statistical summary showed higher mean values of major descriptors in distributed groundwater samples compared with source groundwater samples. A total of 50 drinking water samples (16 from source, and 34 from distribution system) were examined for physical, chemical and bacteriological parameters, including pH, turbidity, electrical conductivity, total dissolved solids, total hardness, total alkalinity, Ca 2? , Mg 2? , Na ? , K ? , SO 4 2-, Cl -, NO 3 -, F -, arsenic (As) chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb). Varying concentrations of trace amounts of Cr (in 8 samples), Fe (18 samples), Cu (18 samples), Zn (13 samples) and Pb (14 samples) were detected. However, the detected trace elements were within the WHO permissible limits for drinking water except Pb where 5 out of 14 samples showed higher than WHO limit value (Pb [ 0.01 mg/L). 19 out of 50 samples (6 from source and 13 from distributed samples) showed high values of alkalinity ([250 mg/L). All of 16 groundwater samples from source exceeded 0.01 mg/L WHO limit value for arsenic (As). On the basis of bacteriological analysis, 42 % samples (12 % from source, 55 % from distribution) did not meet WHO guidelines and were unsafe for drinking, especially distributed groundwater samples. Mg-HCO 3 contents predominated the groundwater type followed by Ca-HCO 3 . Carbonate weathering was revealed to be the dominant process controlling dissolution/precipitation processes. PHREEQC modeling showed that the aqueous phase was undersaturated with respect to significant gypsum, halite and mirabilite while equilibrium to saturated with respect to aragonite, calcite and dolomite was observed. Principal component analysis (PCA) revealed that the concentration of As was strongly associated with that of SO 4 2-. Reductive dissolution and pH-dependent desorption are the plausible processes responsible for the observed high As concentrations in Lahore.

Middle East has suffered from drought since many decades because of climate changes; therefore, surface water has become scarce in many countries such as Iraq. It seems, in general that groundwater is the alternative best solution to cover the lack in water requirements of domestic, agriculture, and industry. In this study, environmental assessment was carried out for 29 wells in Najaf Governorate to evaluate their water suitability for irrigation use. This bases on comparison between 8 water quality parameters with their limitations at Food and Agriculture Organization guideline (FAO) beside British Colombia guideline (BC), the parameters are: nickel, chromium, lead, zinc, cadmium, sulfates, hydrogen power (pH), and total dissolved solids. The study outcome clarifies that there are only 4 wells have suitable water for irrigation use, the others have at least one parameter not applicable with the international guidelines of FAO and BC, which are probably not appropriate for irrigation.