Assessments of Water-Soluble Inorganic Ions and Heavy Metals in Atmospheric Dustfall and Topsoil in Lanzhou, China.

Yingquan Li,Baowei Zhao,Juexian Cai,Wujiang Niu,Kaixiang Duan,Xiao Dong

doi:10.3390/ijerph17082970

Abstract

The chemical features of atmospheric dustfall and topsoil in the same region could reflect the processes of the migration, transport, and diffusion of pollutants in the atmospheric-soil system. Samples of atmospheric dustfall and topsoil were collected in Lanzhou City. The contents and correlation of water-soluble inorganic ions (WSIIs) and heavy metals in dustfall and topsoil were analyzed, the sources of heavy metals and WSIIs in dustfall were distinguished, and the potential ecological risks of heavy metals in dustfall and topsoil were evaluated. The highest contents of WSIIs are SO42− (18,594 mg·kg−1) and Ca2+ (10,070 mg·kg−1) in dustfall, and for SO42− (8271 mg·kg−1) and Na+ (1994 mg·kg−1) in topsoil. The concentrations of heavy metals (Pb, Cu, Zn, Cr, Cd, and Ni) in dustfall are considerably higher than those in topsoil. Combustion of biomass and coal, transportation and industrial activities are the major anthropogenic sources of WSIIs and heavy metals in Lanzhou. Pollution of heavy metals except Cr and Ni in dustfall, and Cu, Cr, and Ni in topsoil was up to different degrees, where the pollution of Cd was serious. The risk of Cd in dustfall is high while moderate in topsoil. This research could offer a reference for the atmospheric particle pollution prevention and control in Lanzhou.

Highlights

Atmospheric dustfall is one of the main urban atmospheric particulate pollutants [1,2], and it has important environmental indication function [3]
The communality of each indicator was extracted by principal component analysis (PAC), the compositional patterns were compared among the samples to find out the mutual influence factors
Geo-accumulation index (Igeo ) is an index that reflects the effect of man-made activities and natural geological processes on heavy metal pollution [27,28], and it is described by the Equation (1)

Summary

Introduction

Atmospheric dustfall is one of the main urban atmospheric particulate pollutants [1,2], and it has important environmental indication function [3]. WSIIs such as sulphate, nitrate, and ammonium are hygroscopic [6], which affect the visibility of atmosphere through the absorption and scattering of light [8]. They can affect the acidity and alkalinity of atmospheric precipitation [9]. The atmospheric dustfall’s contribution rate to the accumulation of heavy metals in topsoil ranks first among various exogenous input factors [10].

Methods

Results

Conclusion