Enrichment factor and geo-accumulation index of trace metals in sediments of the ship breaking area of Sitakund Upazilla (Bhatiary–Kumira), Chittagong, Bangladesh

This study reveals that some trace metals were found in sediments of the Sitakund Upazilla of Chittagong, Bangladesh, largely due to ship breaking activities in the area. This was seen when comparing levels of trace metals in the sediments of the study area with the recommended values of unpolluted sediments. Thus, it was inferred that the trace metal concentrations around the ship breaking area were higher than that of the control site, Sandwip, and near the Karnafully River mouth. The trace elements in the sediment samples were significantly correlated with one another. Enrichment factor values of the sediment samples revealed that most of the sediments were minor to severely enriched by trace metals. Sediments of three stations out of 11 stations of the study area were minor to moderately enriched by Cd metal. The geo-accumulation index (Igeo) values of the sediment samples revealed that the sediments of the ship breaking area were affected from slight to strong contamination with trace metals and sediments in two stations of the study area were affected moderately contaminated by Cd metal. Potential contamination indices of the sediment samples indicated that Cr, Zn, As, and Pb were the greatest contaminants.

► The trace metal around ship breaking area was higher than that of control site.
► The geo-accumulation index values of the sediments were moderately enriched by Cd.
► Potential contamination indices of the sediments were affected moderately from Cd.
► This high level of Cd might be due to the runoff from dismantling of old ships.