| The Yunnan-Guizhou region is an important birthplace of traditional Chinese zinc smelting,while the northwest of Guizhou is a famous lead-zinc smelting area.It is also a high background area of element geochemistry.Under the high background of element geochemistry and the superimposed effect of external source pollution,it poses a great challenge to the ecological environment management and population health risk management and control of the karst mountainous area in northwestern Guizhou.In order to understand the "dose-effect" relationship between heavy metals in vegetables and human health,this article takes “agricultural products-human body”as the main research route to analyze pollution characteristics of heavy metal in agricultural products.Based on an in vitro digestion model to determine the bioaccessibility of heavy metals in the edible part of agricultural products,combine the local dietary habits to choose specific supplementary foods to study its impact on the bioaccessibility of heavy metals and safety and health risks.The measures to reasonably reduce the risk of human dietary exposure are of great practical significance to the protection of the health of the local population,and also provide case reference for environmental and health management in similar polluted areas in China.The main research results are as follows:(1)Testing the heavy metal content of 8 kinds of vegetables found that the content of Cu?Pb?Zn?Cd is the highest in the leafy vegetables,which far exceeds the corresponding heavy metal safety limit specified in the national safety standard.This may be due to the large evaporation of leafy vegetables,very easy to occur containing toxic heavy metals and other pollutants,and the amount of leaves more,vulnerable to atmospheric dust heavy metal pollution.However,soybean potato vegetables and corn have lower levels of heavy metals.Compared with the national standards of pollutant limit in food,the heavy metals in Chinese cabbage are more serious than the standard.The exceeding rate of Pb,Zn,and Cd is as high as 100%,and the exceeding rate of Cu is 50%.The degree of heavy metal pollution in vegetables show that cabbage,eggplant,green pepper,Chinese cabbage,and corn are severely polluted,and green beans,potatoes,and kidney beans were moderately polluted.(2)The daily intake and non-carcinogenic risk values of heavy metals in the population are calculated based on the total amount of heavy metals combined with the Monte Carlo model.The results show that the daily intake of Cu,Pb,and Cd of local residents exceeds the prescribed Rf D value,especially Cd.The non-carcinogenic risk values are ranked in the order of Chinese cabbage> green beans> green pepper>kidney beans> eggplant> cabbage> potatoes> maize.Except for Chinese cabbage,the intake of other vegetables will not cause significant dietary exposure risk to the human body.(3)The result show that the bioaccessibility of heavy metals in different kinds of vegetables is quite different,and the order is bean and potato> leafy vegetables>solanum fruits> grains.This may be related to the different target compounds that each metal binds to in the plant body and the different inherent nutrients in the food matrix.The bioaccessibility of various heavy metals is also quite different,the order is Zn>Cd>Cu>Pb.In addition,the population risk value calculated based on the bioavailability found that after the adjustment,the HI of each vegetable has different degrees of reduction in the simulated stomach and intestine phases,and the decline is25.49%-50.41% and 43.65%-65.08%,respectively.Although the HI of pakchoi in the simulated stomach and intestine phases was still greater than 1,it was only considered to be a reduction of 48.14% and 65.08% compared with the total amount.The HI of other vegetables has been far less than 1 after the bioavailability adjustment,and it can be considered that it no longer has a non-carcinogenic risk.(4)The physical and chemical indicators of the food supplement acid soup were measured and found that the acid soup was weakly acidic and rich in calcium,magnesium minerals and lactic acid bacteria.When simulating the digestion of vegetables and sour soup at the same time,it is found that sour soup has a great difference in the degree of influence on the bioavailability of each metal.The order of influence degree is Cd>Pb>Zn>Cu,and the decrease range is 1.16%?23.94%.Among them,the bioavailability of cadmium in beans and potato vegetables(potatoes,kidney beans,and kidney beans)has the greatest impact.In addition,after the addition of sour soup,the HI of each vegetable was significantly reduced during the simulated intestine stage,with a decrease of 1.12% to 54.14%,indicating that eating sour soup can reduce the dietary exposure risk and safety and health risks of local residents.(5)The strains obtained from the sour soup were preliminarily identified as lactic acid bacteria through the method of colony morphology,cell morphology and Gram staining.The gastrointestinal environment tolerance and cadmium adsorption capacity of the strain were further tested.The results show that the strain has a high survival rate in the simulated gastrointestinal environment(stomach: 89.73%;intestine:78.34%),which has a high cadmium adsorption capacity(19.37%).(6)Lactic acid bacteria can reduce the bioavailability of cadmium in vegetables.Compared with the addition of sour soup,the bioavailability of cadmium in cabbage,eggplant,green pepper,green beans,potatoes,corn,and kidney beans further reduced by 17.35%,4.17%,12.64%,13.59%,17.84%,46.79% And 22.93%.In addition,after adding lactic acid bacteria,the HQ of Cd in vegetables further decreased,with a decrease range of 23.22%?62.31%.The Cd exposure risk of pakchoi has been reduced to a safe threshold. |
PDF Full Text Request