Water Quality Index and Heavy Metal Pollution Index of Groundwater Quality: A case Study in Visakhapatnam District, AP.

Abstract

The main objective of the present study was to assess the groundwater quality of selected Mandals in Visakhapatnam district Andhra Pradesh. Fifty samples were collected from hand pumps of various Mandals. Water Quality Index (WQI) and Heavy Metal Pollution Index (HPI) along with Metal Quality Index (MQI) were determined. Physicochemical parameters such as pH, Electrical Conductivity (EC), Total Hardness (TH) and Total Dissolved Solids (TDS) were measured by various standard techniques. Calcium (Ca+2), Magnesium (Mg+2), Chloride (Cl-), Nitrate (NO3 -) and Sulfate (SO4 -2) were analyzed by 930 Compact Ion Chromatograph Flex. Heavy metals such as Lead (Pb), Zinc (Zn), Chromium (Cr), Aluminum (Al), Copper (Cu), Nickel (Ni), Manganese (Mn) and Cadmium (Cd) were analyzed by using 4200 Microwave Plasma – Atomic Emission Spectrometer (MP-AES). Iron (Fe) was analyzed by Cary 60 UV-Visible Spectrophotometric method. The correlation coefficient (R2) of the heavy metals lies between 0.99 to 0.98. The compliance of BIS 10500:2012 for the heavy metal concentration in drinking water was verified. From the current study, it was found that EC, TDS, TH and heavy metals such as Aluminum (Al) and Lead (Pb) exceeded the allowed limits as per BIS 10500:2012 revision. The highest values of HPI and WQI from the fifty groundwater samples are 407.97 and 189.79. The highest value of MQI is 3.36 respectively. An attempt has also been made to draw spatial distribution maps for heavy metals having higher concentrations in the study area.