Impact of Soil on Chemical Composition of Rainwater in Varanasi, India

The rain water samples of three different location viz. Lanka (Banaras Hindu University, campus), Mirzamurad and Babatpur which are relatively free from industrial pollution were examined during south-west monsoon period (July to September,2015) in Varanasi using standaralize collection and analytical techniques for evaluation chemical composition and reaction of water and to estimate the total ionic balance in rain water. The titrimetric techniques was employed to the determination of Cl, CO3, HCO3, Ca, Mg. The NO3, PO4 and NH4 were estimated by colorimetric methods and Na+ and K+ through flame photometer. In view of the above it is concluded that the phenomenon of acid rain poses no special problem in Varanasi, so long as the aerosol state of the air, which is presently alkaline (pH:7.2-8.8) and continuous to remain so. Moreover, rain water deposition may be an important source of nutrients for vegetation in Varanasi, because it is more concentrate in some important plant nutrient ions, both primary (e.g. N, P, K) and secondary (Ca, Mg, S). Input of nutrients into agro-system via rain water deposition needs to be more fully evaluated before estimation of crop budget.