Characteristics And Effects Of Heavy Metals Pollution In Vegetables In The Typical Lead-Zinc Mines In Shuicheng,Guizhou

Lead-zinc ore is a mineral rich in metal lead and zinc elements which are mainly used in the fields of machinery,metallurgy,electrical,military,chemical,pharmaceutical and light industries.Shuicheng County is the main source of lead-zinc deposits in northwestern Guizhou.The heavy metals Pb,Zn and associated heavy metals Ni,Cd,Cr,As,Hg,Cu generated from the mining and smelting of lead-zinc ore will be enriched in the surrounding soil,and will be absorbed by vegetables.Vegetables are the food that the residents around the mining area consume directly and perennially,which is an important way for heavy metals to enter the human body in the mining area and is directly related to the health of the residents.In this study,typical lead-zinc mines in Shanshui County（shanshulin mine,Yongchang mine,and magnolia mine）were selected as the research objects.The surrounding farmland soil and vegetable samples were collected,and content of the heavy metals Pb,Zn,Ni,Cd,Cr,As,Hg and Cu in the soil and vegetables were analyzed and tested.Geo-accumulation index method and potential ecological risk index method were used to evaluate heavy metal pollution in soil,and single pollution index method,comprehensive pollution index method and comprehensive vegetable-soil quality assessment method were used to evaluate heavy metal pollution in vegetables.The evaluation models of non-carcinogenic and carcinogenic effects of heavy metals were used to evaluate the health risks of heavy metal pollution in vegetables;multiple regression analysis,correlation analysis and principal component analysis are used to study the impact of heavy metal pollution in soil on soil enzyme（Sucrase,Urease,Alkaline Phosphatase,and Catalase）activities and heavy metal pollution in vegetables on the resistance indexes of vegetables to malondialdehyde（MDA）,peroxidase（POD）,soluble protein（SP）and soluble sugar（SS）.The research results are as follows:（1）The evaluation of soil heavy metal geo-accumulation index showed that the soil heavy metals Pb,Zn in Shanshulin mining were heavily polluted,the soil heavy metals Pb,Zn,and Cd in Yongchang mining area were moderately polluted,and the soil heavy metal Zn in Yulan mining area was heavily polluted.The evaluation of the potential ecological risk coefficients of soil heavy metals showed that Pb,Cd,and Hg in soil in Shanshulin mining area were very strong ecological risks and Cd in Yongchang and Yulan mining areas were very strong ecological risks.The comprehensive potential ecological risk index（RI）indicated that heavy metals in Shanshulin and Yulan mining areas were very strong ecological risks,and Yongchang mining area was a strong ecological risk.Multiple regression analysis showed that the combined pollution of Pb,Zn,Ni,Cd,Cr,As,Hg,and Cu in the mining area had significant effects on sucrase and urease activities in soil（p<0.05）.（2）Comparing Pb,Cd,Cr,As,Hg,Zn in vegetables with the Sanitary Standard for the Limit of Zinc in Food（GB 13106-1991）,Cu with the Sanitary Standard for the Limit of Copper in Food（GB 15199-94）,and Ni with the FAO/WHO Codex Standard Limit showed that the contents of Pb,Ni,and Cr in Chinese cabbage were 4.17,1.02,and 2.30 times the standard values;the content of Cd in pepper was 1 times the standard value;the content of Pb in potatoes was4.50 times the standard value;The contents of Pb,Ni,Cd,and Cr in soy beans were 1.50,1.37,1.60,and 2.42 times the standard values;the content of Pb in pakchoi was 7.40 times the standard value,and the content of Zn was 1.24 times the standard value;The contents of Pb and Cr in pea tips were 1.23 and 1.22times the standard values;the contents of Pb in radish were 4.90 times the standard values;the contents of Pb and Cr in greengrocery were 2.60 times the standard values.（3）The comprehensive pollution index evaluation showed that cabbage and Chinese cabbage belonged to heavy pollution.The comprehensive quality evaluation showed that the average IICQ of vegetables and soil was 19.91,which was a serious pollution.Non-carcinogenic health risk assessment of heavy metals in vegetables showed that children,young adults,and middle-aged and elderly people took a variety of heavy metal compound non-carcinogenic health risks of Chinese cabbage,pepper,corn,potato,soybean,green beans,cabbage,pea tip,radish,and green vegetables,which Non-carcinogenic health risk index were greater than 1,and there were certain non-carcinogenic health risks.Risk assessment of carcinogenic health of heavy metals showed that Risk _Tof children,young adults,middle-aged and elderly who ate 10 kinds of vegetables such as Chinese cabbage,pepper,corn,potato,soybean,green bean,cabbage,pea tip,radish,and green vegetable were all greater than 10^-4,which belonged to unacceptable range.（4）The results of multiple regression analysis and F-test showed that the effects of the pollution of Pb,Zn,Ni,Cd,Cr,As,Hg,and Cu in vegetables on malondialdehyde（MDA）,peroxidase（POD）,and solubility protein（SP）and soluble sugar（SS）were not significant（p<0.05）.Correlation analysis results showed that the correlation coefficients of Cd,As and POD were 0.396 and 0.379,respectively,which had significant positive correlations（p<0.05）;Cd had significant negative correlations with soluble sugars（p<0.05）.