21-Physical fractionation of trace metals in surface sediments of the Pandoh Lake, Lesser Himalaya, India

Abstract

The seasonal variation during monsoon (August, 2004), winter (January, 2005) and summer (May, 2005) in concentration and distribution of the trace metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn) were investigated in surface sediments and in different grain size fractions of the Pandoh Lake located in the Lesser Himalayan region, Mandi district of Himachal Pradesh State of India. The seasonal variations were attributed to the influence of biological activities, geological/mineralogical changes and anthropogenic activities. The cadmium, Co and Zn were high in bunch of <63 pm size fractions while Cu, Fe, Mn, Ni, and Pb were significantly higher in all the grain size fractions (> 250 pm to <63 pm) in all the seasons, suggest the operation of complex biogeochemical processes operating in the study area. The enrichment factor (EF) for surface sediments revealed that Cd and Co emerged as a pollution threat to the existing biodiversity of the Pandoh Lake. The seasonal trends of Igeo value for the Pandoh Lake surface sediments also showed that Cd and Co are metal pollutants in the Pandoh Lake with geoaccumulation rating of 4 and 1, respectively, in the monsoon season.