Determination of Nemerow’s Pollution Index (NPI) of Alaknanda River at Garhwal, Uttarakhand
CK Jain, DS Malik, Garima Tomar
NPI is a powerful tool for assessing the water quality of a fresh water ecosystem. Water samples were collected seasonally from eight sampling stations during Sep. 2016 - Aug. 2017. NPI was calculated for the water samples in different seasons. Physico-chemical parameters such as water temperature, velocity, pH, EC, TDS, TSS, TAl., TH, DO, BOD, COD, Ca, Mg, Na, K, Cl, F, NO3 and SO4 were measured in this study. Nemerow’s pollution index was calculated some selected water quality variables as pH, Electrical Conductivity, TH, TDS, Cl, Mg, F, Ca, NO3 and SO4. The results were compared with standards of BIS. The Nemerow’s pollution index calculated from the observed parameters, it indicates that an average pH, EC, TH and TDS values of NPI on all sampling stations were 0.90, 0.55, 0.20 and 0.25 respectively. Main cations and anions values were observed below NPI limit as per standards by which pollutant status occurred. All observed values were found under permissible limit. NPI values indicates that river water is in good quality condition throughout the year.