Ecological Risk Assessment Of Arsenic And Thallium In The Soil Around The Ni-Mo Polymetal Mining Area In Songlin,Zunyi,Guizhou

The concentration of arsenic and thallium in topsoil?upland soil and paddy soil?and the concentration of thallium in crops?grains and vegetables?around the Ni-Mo polymetallic mining area in Songlin,Zunyi were analyzed using inductively coupled plasma mass spectrometry?ICP-MS?.The potential ecological risk of arsenic and thallium in arable soils and the health risk of thallium in six crops were investigated in the paper.The main conclusions were drawn as follows:?1?The concentrations of As in upland soil and paddy soil ranged from 16.7 mg·kg^-1 to 185 mg·kg^-1(mean,59.7 mg·kg^-1)and 6.4 mg·kg^-1 to 44.6 mg·kg^-1(mean,22.4 mg·kg^-1);and the concentrations of Tl in the upland soil and paddy soil ranged from 1.04 mg·kg^-1 to 4.69 mg·kg^-1(mean,2.11 mg·kg^-1)and 1.12 mg·kg^-1 to 1.93 mg·kg^-1(mean,1.57 mg·kg^-1).?2?The concentrations of Tl in Chinese cabbage,radish,sweet potato,rice,chili,maize ranged from 0.0162 mg·kg^-1 to 1.059 mg·kg^-1.?3?The geoaccumulation index of As in upland soil and paddy soil rating as no pollution,slight pollution,secondary pollution,moderate pollution-heavy pollution,heavy pollution accounted for 9.1%,13.6%,54.5%,18.2%,4.6% respectively,and 41.7%,41.7%,16.6%,0%,0% respectively;and the geoaccumulation index of Tl in upland soil and paddy soil rating as no pollution,slight pollution,secondary pollution,moderate pollution-heavy pollution accounted for 5%,59%,27% and 9% respectively,and the geoaccumulation index of Tl in paddy soil was slight pollution absolutely.?4?The potential ecological risk of As in upland soil and paddy soil rating as slight level,medium level,strong level,accounted for 45.5%,45.5%,9% respectively,and the potential ecological risk of As in paddy soil was slight level absolutely.The potential ecological risk of Tl in upland soil rating as medium level,strong level,severe level accounted for 18%,64%,18% respectively,and the potential ecological risk of Tl in paddy soil were medium level?33%?and strong level?67%?respectively.?5?The health risk index of chili,maize,rice were less than one?no health risk?,and the other three crops?radish,Chinese cabbage,sweet potato?were greater than one,causing a certain degree of health risks to human body for long-term edibling,with a decreasing order of Chinese cabbage>radish>sweet potato>rice>chili>maize.The evaluation results of this study show that the upland soil and paddy soil in mining area has may be affected by the weathering of black shales at the bottom of Niutitang Formation and mineral resources exploitation,the influence of both exist a certain degree of potential ecological risk.