Evaluation of the elemental distribution in soil samples collected from ship-breaking areas and an adjacent island

Abstract

Ship-breaking yards in the world mostly reside along the coastal areas which possess diverse elemental contents due to the presence of heavy minerals. So to explain the heavy elemental enrichment of ship-breaking sites in terms of only anthropogenic contribution is insufficient. While studying elemental distribution of ship-breaking sites, choosing appropriate control sample is vital. To evaluate the elemental distribution in ship-breaking yards of Bangladesh and in an adjacent island (Sandwip), soil samples from each site and some heavy minerals have been analyzed for Na, K, Sc, Cr, Fe, Co, As, Sb, Cs, La, Ce, Sm, Hf and Th abundances by neutron activation analysis. For assessing elemental distribution, pollution load index (PLI), geo-accumulation index and inter-element correlation study were performed. Co-related variation of Cr and Fe (r = 0.651) and chemical compositions of heavy minerals invoke that a significant portion of elemental enrichment in ship-breaking yards seems to have mineralogical origin while the enrichments of As, Sb and Cs (mean abundances: 11.3 ± 3.9, 5.66 ± 4.97 and 10.9 ± 6.6 ppm, respectively) are solely originated from anthropogenic activities (e.g., ship-breaking). On the other hand, elemental distribution of Sandwip (which is sometimes used as control sample) seems to be unaffected by the mainland ship-breaking activities and possesses crustal origin, though a minute fractionation of heavy metals is observed within the east (PLI: 0.84 ± 0.05) and west (PLI: 0.52 ± 0.04) side of the island. For the first time, this study reveals the mineralogical contribution of heavy elements in ship-breaking site and will be decisive for choosing proper elemental abundances of control site.