P.U. MEGHA, S. MURUGAN2 AND P.S. HARIKUMAR
Abstract
To determine the safe setback distances between groundwater abstraction wells and contamination sources, quantitative information is needed about the removal of micro-organisms during its passage through soil. Column experiments were conducted using soil samples collected from areas in and around an artificial canal in India, which is receiving sewage generated in an urban area through various outlets. Lambda phage isolated from the canal was used as a biological tracer and its movement and sorption mechanism was studied to determine the safe set back distance. Two-way analysis of variance was conducted to identify the significant factors affecting the phage survival in soil. Phage adsorption to soil was assessed by Freudlich isotherm. Our study suggests that the survival of lambda phage was highest during low temperature, high moisture content and at a pH range of 7-9. The soil types identified from the study area also had a significant impact on phage survival (p= >0.05). The highest and lowest sorption capacity was obtained in sandy clay and sandy soil respectively. There was a strong negative correlation (r = 0.914) with a significant (p < 0.01) value between adsorption coefficient and the calculated safe distance which means that high sorption capacity score go with low safe distance and vice versa.