In an abandoned coal mining area, gangue, water, sediment, paddy soil, and rice samples were collected from abandoned coal mining region in Xingren County, Guizhou Province, southwest China. Concentrations of total Hg (THg) and methylmercury (MeHg) were measured to show regional dispersion of Hg contamination. Sequential extraction for different Hg species: water-soluble (F1), potassium hydroxide-extractable (F2, fulvic acids-FAs), potassium hydroxide-extractable (F3, humic acids-HAs), nitric acid-extractable (F4), and residual (F5) fractions in gangue, sediment, and soil were investigated as well. High THg concentrations obtained in gangues from mining areas, ranged from 0.37 to 35 mg/kg with an average of 11±8.4 mg/kg. Similarly, sediment samples ranged from 0.15 to 19 mg/kg in THg and from 0.036 to 7.8 ng/g in MeHg. THg concentrations in soils were generally low varying from 0.16 to 0.91 mg/kg, but MeHg concentrations were highly elevated ranging from 0.71 to 11 ng/g. THg and MeHg concentrations in surface water varied from 1.0 to 11 ng/L and 0.008 to 0.37 ng/L, respectively. Rice samples exhibited wide ranges varying from 3.0 to 22 ng/g in THg and from 0.71 to 8.9 ng/g in MeHg. Sequential extraction results showed that fraction F4 was the dominant Hg species in both gangue and sediment, while F3 was the dominant form in soil. Concentrations of n-HAs (difference between total organic carbon (TOC) and HAs) in soil were positively correlated with THg and MeHg in both soil and rice, indicating its Hg bioavailability under certain acidic conditions. The spatial distribution patterns of Hg contamination in the local environment suggested Hg is derived from gangues that dumped and introduced into river banks during historic coal mining activities.