Pollution Characteristics And Health Risk Analysis Of Heavy Metal In Soil-vegetable System

This study takes soil-vegetable system as the research object,analyzing the pollution characteristics,morphology,correlation characteristics and soil physical and chemical properties of heavy metals,and analyzing their potential ecological risk and human health risk.The effect of sewage irrigation may be affected in vegetable planting areas.Therefore,an experimental scheme for removing heavy metals from wastewater by calcium carbonate is designed,and a system for removing heavy metals from water by calcium carbonate adsorption is established.It's a reference to the study of soil and vegetable systems,and it has implications for the rational planning of crop planting,treating of sewage irrigation,and promoting the health of agriculture.(1)The soil physical and chemical properties of the roadside soil-rape system in mountainous area are complex.Road surface dust,organic matter content is higher;rape soil texture size is different,Cu in rape soil has the highest Igeo values is 1.34,which belong to the partial pollution;Zn and Ni are light contamination;The maximum values of As,Hg,Cr,Pb,Cd,Zn,Ni and Cu in rape tissues are within 10 m on the road side.The enrichment capacity of leaves,stems and roots of rape to heavy metals at 5 m is higher than that at 10 m and 30 m.(2)Lycopersicon esculentum soil and Brassica oleracea soil in Penglai fairyland belong to medium pollution,Raphanus sativus soil is the least polluted soil,and the single factor pollution index of Hg in soil is the largest.Pb,Cr,Cd and As are mainly residuals in the whole soil of the study area,and the proportion of the total amount of acid extract from Cd is 14.81%,while the content of active states of Hg(48.98%),Cd(44.44%)and Pb(39.40%)is high.The heavy metal IICQ index Lycopersicon esculentum of soil vegetable system is the largest(3.92),except the soil-Pisum sativum system is mildly polluted,the other is moderately polluted.Lycopersicon esculentum leaves and Spinacia oleracea leaves of Hg enrichment coefficient are higher than other vegetables leaf tissue,Pb mainly accumulated in the stem of Pisum sativum and Brassica oleracea,Pisum sativumto the Cd accumulation ability is weakest,IICQ_V minimum,and the strongest resistance to heavy metals.(3)The single ecological risk indexes of Pb,Cd,Cr and As in vegetable soil in the roadside of mountainous area and Penglai fairyland are all less than 40,indicating a slight ecological risk level.Rape soil reaches a strong potential ecological hazard grade,and Lycopersicon esculentum soil,Raphanus sativum soil,Pisum sativum soil,spinacia oleracea soil,brassica napus soil and brassica oleracea soil reach a moderate ecological hazard grade.(4)The long-term consumption of spinacia oleracea leaves,brassica napus leaves,Raphanus sativum leaves and rapeseed leaves produce in the study area may have a certain degree of health risk to human body,but there is no chronic toxic effect.The contribution rate of As in vegetables is the largest,and the potential health risk posed by As is the biggest.