Spatial variability and hotspot prediction of heavy metal pollution in soil-rice system: based on a new geostatistical method

ABSTRACT

The goal of this research was to better understand the spatial characteristics and hot areas of heavy metal concentrations in the soil-rice system, which was critical for implementing heavy metal pollution prevention and control strategies. The amounts of heavy metals in soil-rice were determined using high-precision testing methods such as XRF, ICP-MS, and AFS based on the systematic collection of 285 pairs of soil-rice samples from Wanjiang Economic Zone, China. The Getis-Ord index, Kriging method, and geostatistical method were used to reveal the spatial distribution of heavy metal contamination hot spots in the soil-rice system. The results revealed that the average concentration of heavy metals in soil was Zn>Cr>Cu>Pb>Ni>As>Cd>Hg, whereas it was Zn>Cu>Ni>Cr>Cd>As>Pb>Hg in rice. The average concentrations of heavy metals in the soil were all well below the maximum allowable limit, except for Cd, which was slightly above the allowable limit. Only Cd and Ni concentrations in rice exceeded the maximum permitted limits. In soil, Cd, Hg, Pb, and Zn pollution hotspots were mostly found in the southeast, while Cr and Ni were mostly found in the northeast. An intriguing discovery was that there was a weak relationship between heavy metal concentrations in soil and rice and the spatial pattern of their distribution. The study’s findings offer a scientific foundation for establishing a long-term agricultural development strategy for the soil-rice system in the Wanjiang Economic Zone.

KEYWORDS:

• Spatial variability
• hotspot prediction
• geostatistical technique
• heavy metal
• soil-rice system
• Wanjiang Economic Zone

Acknowledgments

We thank the testing and analysis laboratory of Anhui Jianzhu University for its support and help in sample testing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Dun Wu and Hai Liu proposed the methodology for conducting this study, and were responsible for the collection and testing of relevant samples, and the writing of manuscript concentrations. Xia Gao and Bo Li was responsible for drawing the Tables and Figures in the manuscript. Ndhlovu kataza nyasha was responsible for the manuscript language check.

Consent for publication

All the authors have agreed for authorship, read, and approved the manuscript, and given consent.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/03067319.2023.2198644.

Ethics declarations

All authors have read, understood, and have complied as applicable with the statement on ‘Ethical responsibilities of Authors’ as found in the Instructions for Authors.

Additional information

Funding

The authors acknowledge the support from the Anhui Provincial Key Research and Development Plan [1804a0802198, 201904a07020071].