Water Quality Pollution Indices to Assess the Heavy Metal Contamination, Case Study: Groundwater Resources of Asadabad Plain In 2012

Background & Aims of the Study: Due to the increasing pollution of water resources, towdocumented methods: the Heavy metal potential index (HPI) and the Heavy metalevaluation index (HEI) were evaluated for their suitability for contamination monitoring ofheavy metals (As, Zn, Pb, Cd and Cu) contamination in groundwater resources of AsadabadPlain during spring and summer in 2012.Materials & Methods: In this analytical observational study, concentrations of heavymetals have been evaluated at 30 important groundwater sampling stations. For thispurpose, collect samples in pre-cleaned, acid-soaked polyethylene bottles. Add 2 mL concHNO3/L sample and mix well. Cap tightly and store in refrigerator until ready for analysis.Metal concentrations were determined using inductively coupled plasma- optical emissionspectrometry (ICP-OES).Results: The results showed that mean concentrations of As, Zn, Pb, Cd and Cu ingroundwater samples in spring season were 52.53±13.62, 15.51±23.45, 10.10±2.80,4.48±1.80 and 8.63±10.87 μg l−1, respectively and in summer season were 57.60±16.90,14.99±17.66, 9.28±2.46, 4.57±1.73 and 10.45±10.30 μg l−1, respectively. Therefore themean values of indices in samples from spring and summer seasons were 25.61 and 27.28respectively for HPI and were 9.29 and 8.88 respectively for HEI, and indicates lowcontamination levels. Comparing the mean concentrations of the evaluated metals withWHO permissible limits showed a significant difference (P<0.05). Thus, the meanconcentrations of the metals were significantly lower than the permissible limits.Conclusions: Despite of the heavy metal pollution of the groundwater resources inAsadabad Plain is lower than WHO permissible limits, but the irregular and long-termusage of agricultural inputs, use of wastewater and sewage sludge in agriculture, over useof organic fertilizers and establishment of pollutant industries can threaten the groundwaterresources of this region and cause adverse effect for consumers.