Metal Geochemistry and Contamination Assessment of Tropical Mangrove Sediments

The objective of this study was to evaluate the metal geochemistry and contamination assessment of the metals such as Fe, Co, Cd, Pb, Ni, Zn, Mg, Ca, and Sr from the surface sediment samples collected from seven stations from a tropical mangrove area in the Southwest coast of India. Metals like Ni and Fe were found in higher concentrations but never exceeded the contamination level in all the seasons whereas Cd was highly contaminated in all the seasons as well as stations. Pollution levels were measured using the indices including contamination Factor (CF), potential ecological risk coefficient (Eir), Enrichment Factor (EF), geoaccumulation index (Igeo), Pollution load index (PLI), Contamination degree (Cdegree), modified contamination degree (mCd) and Hazard Quotient (HQ). However, the level of contamination highlighted Cd has the maximum risk factors from the selected study area. All stations are contaminated by anthropogenic inputs. The pollution load index (PLI) revealed Pazhayangady, Valapattanam, Dharmadom (stations 1,2 and 3), Kumbalam (station5) and Munroe Thuruth (station 7) showed the presence of polluted sediments (PLI> 1).