QU Fei1, WEN Lin hong1, FAN Cheng-wu2, LIU Gui-hua2, QIN Song2*
(1. Institute of Horticulture, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China; 2. Institute of Soil and Fertilizer, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China)
Abstract: In order to prevent and control heavy metal pollution in soil, to build green and pollution-free agricultural industrial base, 257 samples of soils developed from six kinds of different parent materials, including typical sandy shale, paleo-weathering crust, limestone, shale, fluvial alluvium, and mudstone, have been collected in Huangping County, Southeast Guizhou Province, for the determination of Cr, Cd, Pb, As, Hg contents and pH values in soils, the comparative analysis of the differences of heavy metal contents in soils developed from different parent materials and the correlations between their heavy metal contents and pH values, and the risk assessment of heavy metals in soils of the study area by using the Hakanson potential ecological risk index method. The results show that contents of Cd are decreased in soils developed from different parent materials in following order from limestone, fluvial alluvium, paleo-weathering crust, mudstone, sandy shale, to shale, Cr contents are subsequently decreased in soils developed from the paleo-weathering crust, mudstone, shale, limestone, sandy shale, to fluvial alluvium, Hg contents are subsequently decreased in soils developed from limestone, mudstone, sandy shale, fluvial alluvium, paleo-weathering crust, to shale, As contents are subsequently decreased in soils developed from mudstone, limestone, paleo-weathering crust, sandy shale, shale, to fluvial alluvium, and Pb contents are subsequently decreased in soils developed from mudstone, paleo-weathering crust, limestone, sandy shale, shale, to fluvial alluvium, respectively. There are significant differences among the contents of heavy metals in soils developed from different parent materials (p？0.05), with the subsequent decrease of p values of elements from Hg, As, Cd, Pb, to Cr. The correlations between heavy metal contents and pH values of soils developed from different parent materials show that Cd contents are positively correlated with pH values of soils developed from the sandy shale and fluvial alluvium, and Pb contents are positively correlated with pH values of soils developed from the fluvial alluvium, respectively (p？0.05). In addition, there are significant positive correlations between Cd contents and pH values in soils developed from the paleo-weathering crust and between As contents and pH values of soils developed from the fluvial alluvium (p？0.05). There is no significant correlation between contents of heavy metals and pH values of soils developed from other parent materials. The results of single factor pollution index evaluation and Nemerow pollution index evaluation show that the heavy metal Hg was seriously polluted in soils developed from different parent materials. According to the survey result, Hg accounts for a main pollution factor of soils due to its large proportion of mineral resources in Huangping County. The results of ecological risk assessment show that the soil developed from limestone is of medium potential risk, soils developed from other parent materials are of minor risks, with the overall soil assessment result of a slight pollution risk. This shows that the overall soils environmental quality of Huangping County is good and soils are not contaminated by heavy metals. However, problems of high contents of heavy metals in soils caused by the Hg mining in Zhifang Town, the hot spring tourism in Langdong Town, and the coal mining in Shangtang Town should be treated in time under the national prevention and control measures of China.
Keywords: soil; parent material; heavy metal; ecological risk
ACTA MINERALOGICA SINICA Vol. 40, No.6, 2020, page 677-684
