基于机器学习和PLS-SEM的农田土壤重金属污染驱动机制

——以湖南省湘潭县为例

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关键词：重金属;稻田土壤;随机森林;偏最小二乘法结构方程;地理加权回归;空间

中图分布类号：TP181;X53 文献标志码：A 文章编号：1672-2043（2025）11-2764-19 doi：10.11654/jaes.2025-0223

Abstract：Toquantitativelyaesstheimpactofnaturalandsocioconomicfactorsonavmtaldistributioninicepaddysoils，this studyintegratedandomforest（RF），geograpicallyweightedegression（GWR），andpartialleastsquaressructuralequationodeling （PLS-SEM）toconstructanintegratedframework foranalyzingthedrivingpathwaysofheavymetaldistributioninXiangtan County，HunanProvince.Resultsshowedthattheprimaryheavymetalrisks inpaddysoilsinXiangtanwereasociatedwithcadmium（Cd）.We furtheranalyzedthedrivingmechanismsof7heavymetalsexcludingNi）withconcentrationsexceedingthebackgroundvalues.RFmodel showedthe highest characteristicimportance valueof irigation water usageon Cddistribution，whileprecipitationand PM10 had the highest characteristic importance value on mercury（ Hg ），arsenic（As），lead （ Pb ），and zinc （ Zn ）.GWR results demonstrated the significantlyspatialheterogeeityinteefectsofvariousfactorsotedistrbutionofsevenheaymetals.PathayanalysisbasedoPL SEM revealed a directly positive effect of climatic factors on Cd，Pb，and Zn（β =0.50～0.74）. In contrast， soil properties showed a directly negative effect on Hg，As，Cr，and Cu（β=-0.59～-0.47） .Indirect effect analysis indicated that socioeconomic factors，mediated by soil properties，had significant positive effects on Cd，Pb，and Zn distribution β =0.33～0.49）.However， terrain and hydrological factors showed significantly positive effects on Hg ，As，Cr and Cu（β>0.30） .Themediating role of hydrological conditions moderated the directly positive effectofclimaticfctorsonsoilpropertiesandthedirectlyegativeefectofterrainonsoilproperties.Tissudyrevealstheoplex interactionsbetwnnaturalandocioeonoicfactorsineavymetaldistributininpddysoils，provdingsientificevidencetetify the driving mechanism of heavy metal distribution and formulate of efective remediation strategies.

Keywords：eayetal;pddysoil;ndomforest;partialleastsquarsstuctualquationmodeling;geogapcallightedeio; spatial distribution

农田是人们赖以生存、实现经济社会发展的物质基础，全球 60% 以上的灌溉农田位于城市附近，农田土壤环境质量受城市社会经济活动的显著影响[1-2]。（剩余23866字）