The Spatial Distribution And Source Identification Of Lead In Typical Contaminated Areas Of Guizhou Province

Lead is an unnecessary toxic heavy metal element to human body.Guizhou province have abundant mineral resources,numerous industrial and mining enterprises and severe soil heavy meatal pollution as well.This research takes the typical contaminated areas of Guizhou province as research object investigated lead concentration and lead isotope composition of rock,soil,slag,plant in Wanshan and Kaiyang districts by high-resolution/multiple collector ion coupled plasma mass spectrometer.Based on this,we analysed the spatial distribution and contamination status of lead in soil.Combined distribution of lead concentration with “finger prints” characteristics of lead isotope in tracing contamination source,this research identified the source of lead in soil.This research obtained background value of lead?21.30?g/g?in places with less human activitiy,ample vegetation and ranked lead contamination in soil according to multiple relationship from lead concentration to background value.The east of Wanshan and Kaiyang?11.03-33.58?g/g?have no contamination;the west of Wanshan,north and west of Kaiyang?39.91-54.96?g/g?have mild contamination;mercury ore smelting,traffic hub section of Wanshan and phosphate smelting area of Kaiyang?57.39-84.05?g/g?have middle contamination.The lead concentration decreased from mercury ore smelting area to surroundings proved that lead entered into soil.The lead isotope composition of farm soil in Wanshan focused on ²⁰⁶Pb/²⁰⁷Pb=1.185-1.250,²⁰⁸Pb/²⁰⁶Pb=1.965-2.075 which shared a common range with slag in Wanshan and coal of Guizhou.Moreover,their characteristic value of ²⁰⁶Pb/²⁰⁷Pb?1.218,1.219,1.235?are similar.Both concentration and isotope of lead indicate that the source of lead in Wanshan farm soil mainly comes from industrial and mining activity.The lead isotope composition of forrest soil in Wanshan focused on ²⁰⁶Pb/²⁰⁷Pb=1.135-1.180,²⁰⁸Pb/²⁰⁶Pb=2.090-2.165 which is similar to isotope range of ore and limestone in Guizhou.Futhermore,their characteristic value of ²⁰⁶Pb/²⁰⁷Pb?1.162,1.161,1.178?are close.Both concentration and isotope of lead indicate that the source of lead in Wanshan forrest soil mainly comes from ore mining and limestone weathering.The research method of Kaiyang district is the same with Wanshan distict.Finally,this research find the lead in Kaiyang soil are controlled by mineral smelting and rock weathering at the same time.Varied with strata,the lead concentration in Wanshan lichen present a three stages distribution,signatured by 24.20,51.66,70.93?g/g respectively.The lead isotope composition of lichen in Wanshan focused on ²⁰⁶Pb/²⁰⁷Pb=1.160-1.202,²⁰⁸Pb/²⁰⁶Pb=2.070-2.115.Its characteristic value of ²⁰⁶Pb/²⁰⁷Pb?1.169?is close to ore and limestone?1.161,1.178?.This research conclude that local ore mining and limestone weathering are main sources of lead in lichen.By researching the spatial distribution and source identification of lead in typical contaminated areas,we can understand the geochemistry behavior of lead in surficial environment thoroughly.This research can guide issues like the evaluation of soil quality,prevention and control of heavy metal in soil,recovery of mine environment.