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
Yanyan Li 1  
,   Dan Yang 1  
,   Pengyan Zhang 1, 2  
,   Wenliang Geng 1  
,   Ying Liu 1  
,   Hao Chang 1  
,   Mingzhou Qin 1, 2  
,   Tianqi Rong 1  
,   Jingwen Shao 1  
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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
Collaborative Innovation Center on Yellow River Civilization of Henan Province, Henan University, Kaifeng, China
Pengyan Zhang   

Henan University, 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
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.