[Source Appointment and Health Risk Assessment of Soil Heavy Metals in Typical Wild Mushroom Producing Area in...

Nanhua County in central Yunnan is the largest and most important wild mushroom production area in Southwest China. To precisely quantify the origins of soil heavy metals and evaluate their associated health risks， thereby establishing a robust theoretical foundation for the prevention of soil heavy metal contamination and the safeguarding of human health， 571 surface soil samples were systematically collected from Nanhua County. To elucidate the origins of soil heavy metals， we employed a combination of multivariate statistical analysis and the UNMIX model， which facilitated the identification and quantification of distinct heavy metal sources within the soil matrix. The pollution levels of soil heavy metals in the study area and their potential health risks to humans were evaluated using the geoaccumulation index method and a health risk model based on Monte Carlo simulation. The findings reveal that： ① The levels of As and Cr in the surface soil of the investigated region markedly exceeded the regional background values for Yunnan Province. The spatial pattern of the eight heavy metals was largely influenced by the geological background， yet it exhibited considerable deviations attributable to external influences. ② The primary sources of soil heavy metals in the study area were high geological background sources closely associated with gold-arsenic deposits （17.08%）， atmospheric deposition sources related to coal mining and combustion （17.87%）， mixed sources of transportation and agriculture （12.78%）， industrial and mining activity sources closely linked to lead-zinc deposits （12.66%）， and natural parent material sources （39.61%）. ③ The geoaccumulation index （I_geo） evaluation revealed that the pollution levels of Cd， Cr， Cu， Ni， Pb， and Zn were relatively low， while As and Hg exhibited varying degrees of contamination. ④ The non-carcinogenic health risks of soil heavy metals to the local population were negligible. However， there were notable carcinogenic health risks， particularly for children， with As being the dominant carcinogenic factor. The heavy metal element As and ingestion frequency （IngR） were identified as the main factors influencing human health risks in the study area. High geological background sources closely related to gold and arsenic deposits and natural parent material sources were significant contributors to human health risks and should be prioritized for control， with enhanced monitoring and regulation.