The variations of heavy metals sources varied their aggregated concentration and health risk in sediments of karst rivers - A case study in Liujiang River Basin, Southwest China

Abstract

The sources and health risk variation of heavy metals (HMs) in sediments of Liujiang River Basin were investigated seasonally to clear the control of HMs contamination in karst rivers. The results revealed the exogenous input of HMs should be more prominent in wet season, due to the higher concentration and EF values. PMF identified HMs were mainly from natural, mining and industrial sources. The input of exogenous HMs were influenced by mining and industrial sources in wet season, but primarily by industrial sources in dry season. HI values were overall below 1, suggesting the relatively low non-carcinogenic risk. The TCR values of HMs were generally beyond 10^-6, particularly those of As and Cr even exceeded 10^-4 for children, which expressed a high carcinogenic risk. The sources components of As and Cr suggested preventing the migration of mining contaminants and limiting industrial emission should be essential to Liujiang River Basin.

Keywords: Health risk; Heavy metals; Karst River; Seasonal variation; Sources identification.