Toxicity levels, Ecological risk assessment of Heavy metals and distribution in the surface sediment of Hub River, Hub River estuary and Gadani coast, Baluchistan, Pakistan
By: Monawwar Saleem, Javed Aftab, Syed Imran Hasaney, Sanober Kahkishan, Syed Wsaeem Haider, Mohsin Muzaffar
Key Words: Heavy metal; Contamination factor; Geo-accumulation Index; Potential Ecological Risk Index, Hub River Baluchistan.
J. Bio. Env. Sci. 8(5), 219-232, May 2016.
Fourteen sediment samples were collected from three sites (Hub River, Hub River estuary and Gadani coast) for examining the concentrations and toxicity levels of heavy metals (Cadmium, Chromium, Copper Lead, Cadmium, Zinc, Manganese and Iron) and their concentrations. Furthermore, some factors and indexes, Contamination Factor, MERM-Q, Geo-accumulation Index, and Potential Ecological Risk Index were used for their environmental assessment and pollution status of surface sediments of the study area. The present data has also been compared with the sediment quality guideline. All the values of heavy metals of the study sites lie in the LEL (Lowest Effect Level) except for Cadmium but its values were also below the ERL (Effects Range Low). The results of the Geo-accumulation index of Cadmium indicate that the sediments in most studied stations of the three sites were moderately to strongly polluted (1.72-2.99). According to Geo-accumulation index all studied stations were found unpolluted with respect to Mn, Cu, Zn and Fe, while Pb was found up to moderate values. The contamination factor of each metal was found in the following order Cd>Pb>Cu>Mn>Zn. The contamination factor of the study area shows that this area has Moderate to Considerable contamination. In the present study, the MERM-Q values range 0.08-0.16 with average values 0.11 which indicates that metal concentrations are approximately with 9-21% probability of toxicity to the benthic organisms. The values of the Potential Ecological Risk Index in the studied stations show considerable to very high risk from metal contamination in the following order: Hub River estuary>Hub River>Gadani coast.