Spatial and temporal variation of dissolved heavy metals in the Lijiang River China: Implication of rainstorm on drinking water quality

Abstract

Lijiang River is an essential drinking water source and natural scenery in the Guilin City. For the first time, implications of rainstorm were taken into consideration by investigating spatial and temporal variation of dissolved heavy metals (HMs) in the Lijiang River water. A total of 68 water samples were collected during low flow (normal) season and high flow (rainstorm) season from 34 sampling sites. Dissolved HMs including Cr, Mn, Co, Cu, Zn, As, Cd, Sb, and Pb were found to meet the respective drinking water standards, while higher concentration was observed after the rainstorm season, except for Cr. Multivariate statistical analysis showed Co, Cu, Cr, Zn, Sb, and Pb in normal season are mainly controlled by anthropogenic sources. Furthermore, higher concentration of Mn, Cu, Cd, Pb, Co and Zn during the high flow season is attributed to rainstorm. The water quality index (WQI) showed good grades, and comparatively lower in rainstorm season. The results of health risk assessment revealed that HMs in Lijiang River pose limited health risk, however, As poses potential health risk during rainstorm season. It is suggested to adopt preventive measures in mining activities and industrial waste-water discharge at the river’s upstream and downstream.