An integrated approach to identify quantitative sources and hazardous areas of heavy metals in soils

Identifying quantitative sources and hazardous areas of heavy metals is a crucial issue for soil management. For
this purpose, an integrated approach composed of finite mixture distributionmodeling (FMDM), positive matrix
factorization (PMF) and sequential Gaussian co-simulation (SGCS) was proposed. FMDM was used to establish
background standards and pollution thresholds. PMF supported by FMDM background standards was applied
to estimate the source apportionment. Hazardous areas of single metals were delineated using SGCS with
FMDM pollution thresholds and uncertainty analysis, and overall hazardous areas were defined by the presence
of multiple metals. This integrated approach was applied to a dataset of seven metals as a case study. FMDMindicated
that the distributions of Cr, Cu, Ni, and Zn were fitted to two-dimensional mixture distributions,
representing a background distribution and a moderately polluted distribution. The distributions of Cd, Hg, and
Pb were composed of a three-component lognormal mixture distribution, corresponding to the background,
moderate, and high pollution distributions. Three sources were apportioned. Cr, Cu, Ni, and Zn were dominated
by parent materials. Parent materials contributed 52.6%, 45.8%, and 81.9% of Cd, Hg, and Pb concentrations, respectively.
Human emissions from coal combustion, industrial work and traffic had significant influences on
Hg, Cd, and Pb,with contributions of 49.8%, 26.9%, and 15.6%, respectively. Agricultural practiceswere exclusively
associated with 20.5% of Cd. Overall, hazardous areas exceeding moderate pollution thresholds covered 17.4% of
the total area, corresponding to urban areas and industrial sites,whereas overall hazardous areas above high pollution
thresholds were limited to 0.01% of the total area.
Publication Name: 
Science of the Total Environment
Page Number: 
Lv, Jianshu; Liu, Yang