Distribution and ecological risk of heavy metal(loid)s in surface sediments of the Hai Phong coastal area, North Vietnam

Surface sediment samples were collected from the Hai Phong coastal area, and grain size and heavy metal content were analyzed to estimate the effects of natural and anthropogenic activities. The area comprised five sediment types: fine sand, very fine sand, very coarse silt, coarse silt, and medium silt. Ten heavy metal(loid)s (Fe, Cu, Pb, Zn, Cd, As, Cr, Co, Mn, Mo) were assessed. The average concentration of followed the order of Fe > Mn > Zn > Pb > Cu > Cr > As > Co > Mo > Cd. Cu, Pb, and As were over Interim Sediment Quality Guideline (ISQGs), while Cr, Zn, and Cd were below ISQG levels. Three sediment groups with three levels of heavy metal(loid)s were identified: group 1 was distributed in the river and nearshore, with coarse silt and the highest heavy metal(loid) concentration; group 2 was distributed in the river, nearshore, and offshore, with very coarse silt and high heavy metal concentrations; and group 3 was distributed in the river and offshore, with very fine sand and the lowest heavy metal concentrations. Runoff from the mainland had a significant effect with a high contamination of As, Cu, and Pb in Hai Phong coastal area.