Distribution Characteristics and Risk Assessment of Heavy Metals in Soil and Street Dust with Different Land Uses, a Case in Changsha, China.

Yan Zhang,Chi Peng,Xinxing Wan,Yalei He,Zhaohui Guo,Xiyuan Xiao

doi:10.3390/ijerph182010733

Abstract

Rapid urbanization and industrialization have led to the accumulation of heavy metals in urban areas. The distribution and health risk of heavy metals in soil and street dust were studied by collecting the samples in pairs from different land uses in Changsha, China. The results showed that the average contents of the heavy metals Pb, Cd, Cu, Zn, Cr and Ni in the soil were 45.3, 0.69, 46.3, 220.4, 128.7 and 32.9 mg·kg−1, and the corresponding heavy metal contents in the street dust were 130.1, 3.9, 130.8, 667.2, 223.2, 50.5 mg·kg−1, respectively. The soils in the parks and roadsides have higher heavy metal contents than those in the residential and agricultural areas. The street dust collected from parks, roadsides and residential areas contained higher heavy metal contents than agricultural areas. Significant correlations were found between heavy metals, suggesting similar sources. However, most of the heavy metals in the soil were uncorrelated with those in the street dust. The contents of heavy metals in soil are the results of long-term pollution. Street dust is easily affected by natural or human disturbances, reflecting pollution emissions in a short period. The health risks posed by heavy metals in the soil are acceptable, but the street dust may threaten children’s health, especially in residential areas. Pb, Cr and Cd are the main risk contributors. Reducing the emissions from industrial plants and traffic may reduce the risk of exposure to heavy metals in the street dust.

Highlights

The results indicated that the distribution of heavy metals in the street dust is quite different from that in the soils, e.g., some sites have high heavy metal contents in street dust low contents in the Themetal heavycontents metal contents street are domidust but lowbut contents in the soil
The metalThe contents in soil and street different land gated in heavy average contents of Pb,dust
The street dust collected from parks, roadsides and residential areas contained higher heavy metal contents than agricultural areas

Summary

Introduction

Heavy metals are common persistent toxic pollutants in the environment [1], released from both anthropogenic sources and natural sources, such as the burning of fossil fuels, wear of vehicle tires and brake pads, erosion of paint and coatings, metal mining and smelting activities, and soil parent material [2,3,4]. The rapid urbanization, industrial production and the number of motor vehicles increasing exponentially, causes a large amount of heavy metals to be released into the environment [5]. One of the main carriers of heavy metals in the urban environment, originates from building and road pavement erosion, industrial smoke, and traffic dust [6,7,8]. Distribution and risk assessment of heavy metals in urban soil and street dust has become important.

Methods

Results

Conclusion