Heavy Metal Pollution Evaluation And Health Risk Evaluation In Soil Of Morchella Producing Base In Guizhou Province

In this paper,taking the artificially cultivated morel planting base as the research object,the enrichment characteristics of five heavy metals?Pb,Cd,As,Cu,Zn?in the planting soil and morel were analyzed,and the occurrence forms of heavy metals in soil were analyzed.Using Nemero Pollution Index Evaluation Method,Geoaccumulation Index Method,Hakanson Potential Ecological Risk Index Method,and Health Risk Model to assess heavy metal pollution in soil and Morchella,the main research results are as follows:?1?The heavy metal enrichment characteristics of the soil indicate that the heavy metals in the A,B,C,D and E bases are all enriched to varying degrees.Based on the soil pollution risk screening value,except for the Pb part of the sampling site that exceeds the soil pollution risk screening value,the other four heavy metals in base A do not exceed the screening value;in the soils of bases B,C,and D,except for the presence of different percentages of As and Cd,the sampling sites exceed the soil pollution risk screening value,and the other three heavy metals do not exceed the standard value;only Cd concentration of heavy metals measured at E base exceeds the screening value.?2?The results of the potential ecological hazard index method show that:Base D is a moderate degree of ecological risk,and Cd is the main risk factor that constitutes ecological hazard;Base A,B,C,and E are at a slight level of ecological risk.The results of the Nemero Pollution Index Method showed that the bases A,B,and C are slightly polluted,the base D is heavily polluted,and the base E is under pollution alert.Geoaccumulation index method results showed that:Base E is not contaminated by these five heavy metals,and heavy metal elements Pb,Cd,and As in bases B and C;As and Cd in base C;and Pb in base A require attention.?3?The analysis of soil heavy metal occurrence form showed that for soil heavy metals Cd,bases B,C,D and E take acid extractable state as the main occurrence form,and base A takes residue form as the main form;for soil soil heavy metals Pb,the bases B and C are mainly in the reducible state,and the other bases are mainly in the residue state;for As,Cu and Zn,the five bases?A,B,C,D and E?are mainly in the residue state.For the entire study area,environmental risk index assessment and bioavailability both indicate that Cd is the main environmental risk hazard factor.?4?The study on the enrichment characteristics of Morchella heavy metals showed that the five heavy metal samples of the Morchella in bases B,C,D and E do not exceed the national standard limit value,which met the national food safety standards;but heavy metals Pb and As in base A are out of standard.Bioaccumulation coefficient analysis showed that the enrichment coefficients of Morchella in the five bases are all less than 1.The comprehensive pollution index evaluation of Morchella showed that the pollution levels of bases C and E are still clean,and bases A,B and D are slightly polluted.?5?The risk assessment of heavy metal exposure showed that:in the non-carcinogenic exposure risk assessment,the human body in base A is the most exposed to Pb,and the human body in bases B,C,D and E is the most exposed to Zn;Based on this research,the average carcinogenic exposure of two carcinogenic heavy metals,As and Cd,is As>Cd.The comprehensive non-carcinogenic risk index HI is less than 1,so there is no non-carcinogenic risk in the entire study area;the comprehensive carcinogenic risk index is between 10^-6-10^-4,indicating that these five heavy metal carcinogenic risks are at a human tolerable level,Within a relatively safe range.?6?The health risk assessment of Morchella shows that for adults and children,the health risk index of the five heavy metal single elements in the five bases is less than 1,indicating that Pb,Cd,As,Cu,and Zn pose no potential health risks to the human body harm.The comprehensive health risk index pointed out that the A,C,D and E bases TTHQ are all greater than 1,except for the B,indicating that A,C,D and E heavy metal elements are likely to have a negative impact on the health of exposed people.