Environmental Controls to Soil Heavy Metal Pollution Vary at Multiple Scales in a Highly Urbanizing Region in Southern China

Abstract

Natural and anthropogenic activities affect soil heavy metal pollution at different spatial scales. Quantifying the spatial variability of soil pollution and its driving forces at different scales is essential for pollution mitigation opportunities. This study applied a multivariate factorial kriging technique to investigate the spatial variability of soil heavy metal pollution and its relationship with environmental factors at multiple scales in a highly urbanized area of Guangzhou, South China. We collected 318 topsoil samples and used five types of environmental factors for the attribution analysis. By factorial kriging, we decomposed the total variance of soil pollution into a nugget effect, a short-range (3 km) variance and a long-range (12 km) variance. The distribution of patches with a high soil pollution level was scattered in the eastern and northwestern parts of the study domain at a short-range scale, while they were more clustered at a long-range scale. The correlations between the soil pollution and environmental factors were either enhanced or counteracted across the three distinct scales. The predictors of soil heavy metal pollution changed from the soil physiochemical properties to anthropogenic dominated factors with the studied scale increase. Our study results suggest that the soil physiochemical properties were a good proxy to soil pollution across the scales. Improving the soil physiochemical properties such as increasing the soil organic matter is essentially effective across scales while restoring vegetation around pollutant sources as a nature-based solution at a large scale would be beneficial for alleviating local soil pollution.

Ecological Risk Assessment and Source Analysis of Heavy Metals in Farmland Soil in Yangchun City Based on APCS-MLR and Geostatistics

“…The nuggets for Zn, As, Ni, Cr, Cu, and Cd are between 0.25 and 0.75, indicating moderate spatial variation. The nugget for Hg is greater than 0.75, indicating a high level of spatial variation, suggesting that the spatial situation of the local agricultural land has been strongly influenced by random factors [33], as the input of heavy metals caused by various human activities has already exceeded the input caused by the original structural factors by a large margin.…”

Spatial Distribution Characteristics and Pollution Evaluation of Soil Heavy Metals in Wulongdong National Forest Park

“…Although they are not heavy metal elements, they are heavy metal pollutants (Askari et al, 2020),There are many types of heavy metal elements that can cause pollution. In this study, the metal elements selected for determination in accordance with the long-term observation task indicators of forest soil in the "Terrestrial Ecosystem Soil Observation Speci cations" (Cheng et al, 2022)include: chromium (Cr), nickel ( Ni), lead (Pb), arsenic (As), cadmium (Cd), mercury (Hg), and selenium (Se).…”

“…These processes have signi cantly impacted and disrupted the ecological environment of the forest. (Li et al, 2022;Zhou et al, 2022).…”