Yuexi County, a key tea-producing area in eastern Dabie Mountain, may face potential heavy metal(oid) (HM) contamination risks due to nearby mining and intensive agricultural activities. This study investigated seven HMs (As, Cd, Cr, Hg, Ni, Pb, and Zn) in paired soil–tea samples using multiple analytical approaches, including the geoaccumulation index (I_geo), the potential ecological risk index (RI), bioconcentration factor (BCF), and positive matrix factorization (PMF) with Monte Carlo simulation for health risk assessment. Results showed that Zn (82.65 mg/kg) and Cd (0.15 mg/kg) were the most enriched HMs in soils with higher I_geo values than other HMs. PMF analysis identified four major HM sources: mining and transportation (27.75%), agricultural activities (26.90%), natural soil parent material (26.17%), and industrial emissions (19.18%). Tea plants exhibited selective HM absorption, with Hg showing the highest bioaccumulation (BCF = 0.45), while As, Cr, and Pb had minimal uptake (BCF < 0.05). Although health risk assessments confirmed that both non-carcinogenic and carcinogenic risks from soil and tea consumption were within safe limits for adults and children, Cr and Ni required special attention due to their risk contributions. Overall, ecological and health risks in the region were found to be low. These findings provide important scientific support for pollution monitoring, risk management, and overcoming trade barriers in tea-growing regions with acidic soils. Future research should integrate HM speciation analysis with seasonal monitoring to further optimize tea plantation management strategies.

Heavy metal(oid) pollution in tea plantation has become a global concern threatening tea safety, with food safety serving as the cornerstone of the tea industry. In this study, the distribution and migration patterns of seven heavy metal(oid)s in soil-tea systems developed from three parent materials were investigated, in the geologically complex but minimally human disturbed Dabie Mountains. Results showed that although the heavy metal(oid) concentrations in tea at all sampling points meets the food safety standards of China and the European Union, significant differences existed in the bioaccumulation potential of the elements. Hg and Cd showed the highest bioconcentration factors (mean values of 0.45 and 0.33, respectively), while As, Cr, and Pb transfer were inhibited. Geological type significantly influenced the heavy metal(oid) distributions. Random forest models revealed metal-specific transfer mechanisms, with P-related variables (e.g., soil total P, available P, and microbial biomass P) and microbial C-N acquisition enzyme activities serving as key regulatory factors. This study confirms that parent materials indirectly potentially influence heavy metal(oid) bioavailability by shaping soil development and microbial functions, providing scientific basis for geology-informed food safety risk assessment in tea plantations.