Source Identification of Cd and Pb in Typical Farmland Topsoil in the Southwest of China: A Case Study

Junji Zhang,Xinyu Wang,Zeming Shi,Fei Wei,Shijun Ni,Chao Liao

doi:10.3390/su13073729

Abstract

Cd and Pb in farmland topsoil are controlled by many factors. To identify the source of potential toxic metals in the farmland topsoil around Mianyuan River, the chemical analysis and multivariate statistical analysis are performed in this study. The results indicate the following: (1) The concentration of Cd and Pb in soil exceed the background value of Chinese soil elements. (2) Cd is significantly enriched in the whole region and Pb is locally enriched, both of them are more or less influenced by human activities. (3) The contents of Cd and Pb increase significantly following the flow direction of river. (4) Pb isotope analysis indicates that the main source of Pb in the soil include the air dust, coal and phosphate plant, and the contribution of them decreases successively. (5) Linear correlation analysis and principal component analysis show that the main sources of Cd in the soil are mining phosphate rock, air dust, phosphate plant and coal mining.

Highlights

The average contents of Pb, Cd, Cu, Zn, Cr, Ni, Hg, Se, and P exceeded the reference value, and the level of Cd exceeded the reference value more than 10-fold, which indicates that the potential toxic metals in the farmland topsoil of the study area were enriched
Potential toxic metals contributed primarily by natural sources have low CV values, while those affected by human activities generally have high CV values [35]
This indicates that the concentrations of Cd, Pb, Zn, Hg and P have significant spatial heterogeneity, and their production may be dominated by human activities [36]

Summary

Introduction

The toxicity and bioavailability of potential toxic metals (such as Cd and Pb) in soils have recently attracted increasing levels of public attention [1,2,3]. Lead is a priority heavy metal pollutant, as designated by the. Cd pollution is mainly caused by the soil parent material, soil type, water system [7], dustfall [8,9] and human activities [10]. Previous studies have found that the mining and smelting of metalliferous materials, electroplating, gas exhaust emissions, energy and fuel production, and fertilizer and pesticide application are the main ways that human activities cause Cd pollution [11]. Anthropogenic factors are playing an important role in potential toxic metals contamination [12]

Methods

Results

Conclusion