Ecological Risk Posed by Heavy Metals Contamination of Ship Breaking Yards in Bangladesh

Pollution of water and soils by heavy metals is an emerging problem in industrialized countries. The present study was conducted to investigate the heavy metals concentration in water and sediment samples from ship breaking sites of Sitakunda to assess the potential ecological risk posed by heavy metal using different methods. Heavy metals concentration was analyzed by Atomic Absorption Spectroscopy. Concentrations of all the tested heavy metals except Cr in water samples of ship breaking site, Sitakunda were lower than recommended values. The mean concentration of Cr was found 0.511± 0.284 mg/l. Concentrations of all the tested heavy metals except Mn in sediment samples were higher than standard limit. The concentrations of Pb, Mn, Cr, Cu and Zn in the sediment were 55.93±18.70, 20.08±4.03, 106.8±47.65, 50.09±18.31, and 70.71±19.45 mg/kg, respectively. Based on Geoaccumulation Index, Contamination factor, Sediment Quality Guidelines, the sediment of ship breaking site can be treated as unpolluted to moderately polluted with Pb, Zn, Cr and Cu but unpolluted with Mn. The Enrichment factors of Pb, Mn, Cr, Cu and Zn in the sediment were: 2.97±0.98, 0.035±0.008, 1.97±0.88, 1.99±0.73, and 1.17±0.32, respectively. The Enrichment factor ( > 1) in all sampling sites, suggesting source of those metals (Pb, Cr, Cu and Zn) were more likely to be anthropogenic. Based on the Potential Ecological Risk Index the ship breaking site posed to low risk to the environment. The results of present study clearly indicated that the ship breaking site was moderately polluted with heavy metals and pose low risk to the ecosystem.