Abstract: This paper analyzed the spatial distribution of mercury (Hg) in the soils and surface waters in Guizhou Province. The geo-accumulation index and potential ecological risk index were applied to assess the pollution degree and the ecological risk of total mercury (THg) in soils, and the single factor method and safety threshold method were employed to evaluate the THg pollution degree and the ecological risks of reactive mercury (RHg) and methylmercury (MeHg) in surface waters, respectively. The results showed that in the soils close to mercury-related mines and factories, there was a higher THg pollution. Of the 23 soil samples from the mercuryrelated mines and factories, the extreme, severe, and moderately severe THg pollution occupied 78.26%, 13.04%, and 8.70% of the total samples, respectively. Meanwhile, the potential ecological risk of THg in the soils was extremely high. In the other areas, soil THg pollution was moderate, and the potential ecological risk was acceptable. The THg pollution in the surface waters close to mercury mines, lead-zinc mines, and organic chemistry factories was serious, but the ecological risk to aquatic organisms was negligible due to the low concentrations of RHg and MeHg.

Key words: natural disturbance, human disturbance, seed dispersal quantity, seed dispersal distance, seedling regeneration.