Heavy metal pollution levels, source apportionment and risk assessment in dust storms in key cities in Northwest China.

In this study, the potential hazards of heavy metals in dust storms were investigated by collecting dust storm samples, measuring their heavy metal concentrations, and using index evaluation, spatial analysis, positive matrix factorization (PMF) model and risk assessment model. Heavy metals in dust storms were contaminated by anthropogenic sources leading to their concentrations being higher than the background values. The enrichment factors and geoaccumulation indices showed that the heavy metals came from both natural and anthropogenic sources, Cu, Ni, Zn and Pb are strongly influenced by anthropogenic sources. Heavy metals in dust storms were divided into four sources: Cu and Ni were attributed to industrial sources mainly from local mining and metal processing; Cr was mainly contributed by industrial sources related to industrial production such as coal combustion; Pb and Zn were mainly contributed by transportation sources; and Ti, V, Mn, Fe, and As were from natural and agricultural sources. The level of comprehensive ecological risk of heavy metals in dust storms were low, but there were moderate and above risks at individual sites. Both adults and children had the highest carcinogenic and non-carcinogenic risks from the ingestion route, and the risk for children was higher than that for adults.