ORIGINAL RESEARCH
Optimal Interpolation and Ecological Risk
Assessment of Spatial Distribution of Heavy
Metals in Soil Based on GIS and Geostatistics
– A Case Study of Low-lying Land
of the Lower Yellow River, China
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1
Key Laboratory of Geospatial Technology for Middle and Lower Yellow River Region, Research Center of Regional
Development and Planning, Institute of Agriculture and Rural Sustainable Development, Henan Overseas Expertise
Introduction Center for Discipline Innovation (Ecological Protection and Rural Revitalization along
the Yellow River), Henan University, Kaifeng, China
2
Collaborative Innovation Center on Yellow River Civilization of Henan Province, Henan University, Kaifeng, China
Submission date: 2020-07-25
Final revision date: 2020-10-23
Acceptance date: 2020-11-04
Online publication date: 2021-04-08
Publication date: 2021-04-16
Pol. J. Environ. Stud. 2021;30(3):2631-2644
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ABSTRACT
Soil environmental quality plays an important role in ensuring human health and food security.
Therefore, increasingly attention has been paid to the ecological and environmental problems affecting
river basins worldwide. The Yellow River is the second longest river in China and the fifth longest river
in the world, thus it has great significance globally and locally. In recent years, the ecological protection
and exploitation of the Yellow River Basin have attracted much attention, especially regarding changes
in vegetation, water, and sediment, as well as soil quality problems. This research concentrates on the
assessment of soil heavy metals in the low-lying land, a typical landform unique to the Yellow River
Basin, which is of great significance for the study of food security, cultivated land protection, and
cultivated land resources in developing countries. Here, 156 surface soil (0-20 cm) samples, and eight
elements (Cd, Cr, Ni, Pb, Cu, Zn, As, and Hg) were collected to be measured and studied. We found that
only the average value of Cd exceeded the standard. By comparing the above six interpolation methods,
the optimal interpolation model was selected for the analysis of the spatial distribution characteristics of
the heavy metal content in eight soils in the study area. Regarding the spatial distribution, we observed
that higher concentrations in the west, with lower concentrations in the east; all heavy metals exhibited
high-value zones. The evaluation of the potential ecological risk index revealed that only Cd reached
the moderate level. Zn, Pb, Cd, and Hg were greatly affected by anthropogenic sources, and Cu, Cr, Ni, and As were greatly affected by natural sources. Therefore, Cd was found to be the main risk factor
in the region and Cd soil levels should thus be closely monitored in the study area.