Spatial distribution, origin and contamination assessment of heavy metals in surface sediments from Jangsong tidal flat, Kangryong river estuary, DPR Korea

This study aims to investigate spatial distribution, contamination and origin of heavy metals (Pb, Zn, Cu, Ni, Co and Cr) in surface sediments of Jangsong tidal flat (JTF), Kangryong river estuary, DPR Korea, where has been affected by various mining activities. The spatial diverse of heavy metals are due to differences in their sources and sediment properties. Enrichment factor, geoaccumulation index and ecological risk indexes indicate that JTF is not polluted and has low ecological risk, although slight enrichments occur for some metals. Multivariate analyses revealed that Mn, Ni and Cr originated from lithogenic source, whereas other metals were of anthropogenic origin, among which Fe and Co originated from the iron mine settling pond near JTF, while Pb, Zn and Cu originated from AMD effluent by sulfide mining activity in catchment of JTF. The different transport mechanisms of heavy metals from AMD result in diverse distribution of the metals in JTF. •The heavy metals in estuarine sediments affected by various mining activities.•The sediments are largely silty sand, with anthropogenic clay and abundant OM.•Spatial diversity of heavy metals due to differences of their sources and behaviors.•A slight enrichment for Pb, Co, Zn and Cu was observed in JTF but not polluted.•Pb, Zn and Cu originated from AMD, but were differentiated during transport.