Abstract: The contents and distribution characteristics of six heavy metals (Sb, As, Cd, Zn, Pb, Mn) were investigated by sampling soil and different parts of Polygonum capitatum from Dushan antimony deposit in Guizhou. The results showed that the contents of Sb, As, Cd, Zn, Pb and Mn in soil samples were 1566.55, 23.98, 1.21, 117.81, 34.27 and 460.98 mg·kg^-1, respectively. The contents of Sb, As, Cd and Zn were 699.35, 1.20, 4.88 and 1.18 times higher than the soil background values in Guizhou, respectively. In addition, the correlation between Sb and As in soil was significant (P<0.05), showing a homologous pattern. The evaluation using Nemerow comprehensive index showed that the pollution index of soil heavy metals in this area ranged from 112.75 to 1295.22, with an average of 500.37, indicating the serious pollution. Besides, P. capitatum showed good growth and tolerance in the soils contaminated by antimony mining. The Sb and Mn contents in P. capitatum were in order of root > leaf > stalk > flower and leaf > flower > root > stalk, respectively, but As, Cd, Zn and Pb exhibited no obvious pattern. Although As, Cd, Pb contents in P. capitatum were lower than the maximum limits of heavy metals in natural materials of Traditional Chinese Medicine (ISO 18664), Sb in Polygonum capitatum may be harmful to human health.

Key words: drinking water, adsorption, coagulation, membrane filtration., fluoride, risk control