<![CDATA[An assessment of the content of mobile (labile) forms of heavy metals (HMs) – As, Hg, Cr, Zn, Cd, Pb, Cu – in the soils of Bidoup-Nui Ba National Park (Lam Dong Province, Vietnam) was conducted. The study was carried out on a key site representing a catena in a tropical forest with a predominance of yellow ferrallitic soils. Samples were collected in the dry and wet seasons from various genetic horizons. All analyzed elements were detected in all samples. A clear seasonal pattern emerged from our data: concentrations of labile heavy metal forms were consistently elevated during the dry period compared to the wet season, with differences reaching up to 10-fold for certain elements. Exceedances of Russian MPC standards for mobile forms were noted for lead (Pb) in four samples (up to 13.1 mg/kg) and for zinc (Zn) in three samples (up to 100.97 mg/kg) in the dry season. Calculated hazard coefficients (K?) showed that in the dry season, the potential environmental hazard associated with mobile forms of Pb and Zn is higher (average K? = 0.76 and 0.98, respectively) than in the wet season (average K? = 0.29 and 0.16). High positive correlations were found between the contents of all studied HMs in mobile form (r = 0.83-0.97), indicating their coupled migration and possibly common sources of input or accumulation conditions. The obtained data characterize for the first time the ecological and geochemical state of the soils of this protected natural area in terms of the content of bioavailable forms of HMs. The results indicate the need for monitoring mobile forms of HMs even in background territories, as their accumulation, especially in the dry season, can create potential environmental risks due to inclusion in trophic chains.]]>
