Metal contamination assessment in a sediment core from Vagamon Lake, southwest India: natural/anthropogenic impact

Abstract Trace elements and grain size parameters of a sediment core collected from Vagamon Lake, situated at the edge of Western Ghats, were analyzed. The ascending order of average concentration of metals is showing the following order - Al > Fe > Ti > Mg > Mn > Cr > Zn > Ni > Pb > Cu > Co > As > U>Cd. The metals are not showing a good correlation with the textural parameters, which indicates the grain size is not controlling the metal distribution in the study area. The enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), modified degree of contamination (mCd), and pollution load index (PLI) calculated to assess anthropogenic contamination. Results showed moderately-strongly As contamination in the region. Statistical analysis, such as Principal Component Analysis and Cluster Dendrogram analysis carried out to determine possible interrelationships between the different metals and textural parameters in the Vagamon sediment core. The results indicated that As could be attributed to anthropogenic sources and may be predominantly affected by human activities. Also, the moderate pollution of the elements like Zn, Ni, Cr and Pb may be associated with both natural and anthropogenic sources. The gradual increase of this As contamination is a threat to the plants, human beings and the other biota. Present-day tourism activities, increasing constructions and usage of fertilizers-pesticides-insecticides at the Vagamon area contribute to this alarming situation.