Distribution and risk analysis of heavy metals in sediments from the Yangtze River Estuary, China

Distribution and risk analysis of heavy metals in sediments from the Yangtze River Estuary, China:

Abstract

Sediments core within the Yangtze River Estuary was collected for metal and grain size analysis. The vertical distribution characteristics of eight metals along the core were investigated based on ¹³⁷Cs and ²¹⁰Pb radionuclide dating. The sediment was mainly composed of sand and silt. The metals concentrations were Al, 4.67–6.83; Fe, 2.3–3.94; Mn, 0.046–0.07; Cr, 69.5–103; Cu, 14.3–32.1; Zn, 47.3–96.7; Cd, 0.037–0.212; Pb, 13.7–23; Ni, 18.8–38.9 (mg·kg⁻¹, except Al, Fe, and Mn as %), respectively. Geoaccumulation indexes (I_geo) indicated that Cu, Zn, and Pb were of pollution-free level; Cd, Cr, and Ni were in a slight polluted level. Based on potential ecological risk factors (EI), Cd posed a moderate risk to the local environment. Correlation analysis showed that Fe, Al, and Mn had a close association with Cu, Zn, Pb, and Ni at p < 0.01. Clay was significantly correlated with other metals except Cr and Cd.