Multiple regression analysis of data on river Ganga in Varanasi city region with special emphasis on lead(ii) and cadmium(ii)

Abstract

Detailed studies on the river water of the Ganga for a period of three years i.e. 1986 to 1988 of nine selected sampling stations at the sewer‐river confluence points in the Varanasi city region were undertaken. The frequency of sampling was once a month for each year except for the monsoon months of July, August and September. Emphasis has been given to fourteen relevant parameters i.e. temperature, pH, chloride, alkalinity, D.O., C.O.D. with special significance to the eight heavy metals viz. Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb. The data obtained were subjected to a multiple regression analysis and the two equations relating to the most pertinent parameters, lead and cadmium, were developed wherein the other parameters were taken as independent variables. The equations are given below: Cd = ‐91.868 ‐1.374 × temperature + 10.198 × pH + 0.674 × chloride ‐0.082 × alkalinity + 2.269 × D.O. ‐O.051 × C.O.D. + 0.061 × Cu ‐0.093 × Cr + 0.063 × Mn + 0.126 × Ni + 0.116 × Zn Pb = ‐44.208 + 0.607 × alkalinity + 7.152 × D.O. + 0.804 × C.O.D. + 0.049 × Cu ‐0.295 × Cr + 0.281 × Co + 0.222 × Mn ‐0.494 × Ni.