ORIGINAL RESEARCH
Spatial Distribution and Migration of Cadmium
in Contaminated Soils Associated with
a Geochemical Anomaly: A Case Study
in Southwestern China
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1
College of Resources and Environmental Engineering, Guizhou University, Huaxi District, Guiyang, P.R. China
2
College of Agriculture, Guizhou University, Huaxi District, Guiyang, P.R. China
3
Guizhou Provincial Academy of Agricultural Sciences, Huaxi District, Guiyang, P.R. China
Submission date: 2018-04-14
Final revision date: 2018-08-28
Acceptance date: 2018-09-04
Online publication date: 2019-05-31
Publication date: 2019-07-08
Corresponding author
Hongyan Liu
Guizhou University, Huaxi District, Guiyang, Guizhou province, 550025 Guiyang, China
Pol. J. Environ. Stud. 2019;28(5):3799-3807
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ABSTRACT
The karst terrain of Guizhou in southwestern China is ecologically fragile, but has undergone
severe heavy metal contamination. To assess such contamination, the spatial distribution of cadmium
(Cd) within soils was studied in a lead (Pb)-zinc (Zn) smelting area, coal mining area, Pb-Zn mining
area, sewage irrigation area, and an uncontaminated area. Cd concentrations were highest in topsoil,
with the highest value of 23.36 mg/kg in the Pb-Zn mining area and lowest value of 0.46 mg/kg
in the uncontaminated area. Cd content decreased from 0 to 0.8 m depth, then sharply increased,
reflecting Cd precipitation within the contaminated soil profiles. Migration of Cd within the soil was
affected by organic content in the Pb-Zn smelting area (R2 = 0.99**), coal mining area (r = 0.72*),
and Pb-Zn mining area (r = 0.73*). In contrast, Cd accumulated within a clay horizon in
the uncontaminated area, where the correlation between Cd and specific surface area was 0.78**;
Cd concentrations reached 2.11 mg/kg within this horizon. Reducible, oxidizable, and acid-exchangeable
fractions accounted for 60-80% of total Cd in soils having pH values of 5.05-6.86. This indicates that Cd
could easily transfer from soil to food or water, leading to human health and environmental risks.