Characterization and risk assessment of metals in surface sediments and riparian zone soils of Liaohe River, China

Characterization and risk assessment of metals in surface sediments and riparian zone soils were studied in Liaohe River, northeast China. Surface sediment and riparian soil samples were collected from 24 monitoring sites along 538 km of Liaohe River. Metal concentrations and enrichment factors of Zn, Cr, Pb, Cu, Ni, and As were analyzed. Potential sources of metal contaminants along with ecological risk assessment and health risk via ingestion, inhalation, and dermal contact for residents were also assessed. Metal concentrations followed the order Cr > Zn > Cu > Ni > As > Pb in surface sediments, and Cr > Zn > Cu > Ni > Pb > As in riparian zone soils. The degree of metal pollution in Liaohe River sediments and riparian soils was considered moderate and is showing signs of recovery compared to historical concentrations reported previous studies. Enrichment factors also indicated metal pollution was not severe in both riparian and river sediments and were mainly derived from natural sources. Children had significantly higher health risks along the Liaohe River, and oral ingestion was the dominant exposure pathway. The major non-carcinogenic metal was Cr, and As was the main carcinogenic metal. Although carcinogenic and non-carcinogenic health risks of metals were considered low for both children and adults along the Liaohe River, future monitoring of metal contaminants, especially for As and Cr is recommended.