Accumulation,Translocation And Health Risk Assessment Of Cd In The Soil-Crop System In Guangzhou

Taking Guangzhou city as the main research area,based on the Cd content of soil and crop,using the single factor evaluation method,the surface soil heavy metal activity evaluation method and the agricultural product safety evaluation method to evaluate the Cd content of soil and crop,to explore the correlation of soil-crop system of Cd and enrichment regularity,to establish the accumulation model.Finally,to evaluate the health risks of Cd consumption by leafy vegetables and rice in the study area.On the other hand,the most commonly eaten staple food in Guangzhou includes rice and rice products.And flowering cabbage and lettuce are the two most popular vegetables in Guangzhou’s dining culture,among vegetables,many studies have found that leafy vegetables are the varieties with the highest concentration of heavy metals.Therefore,it is reasonable to choose rice,lettuce and flowering cabbage as research targets.After analysis and research,the main conclusions are as follows.The Cd accumulation has been found in the agricultural sampling area and has exceeded the Cd background value of Guangdong province.After performing a Cd pollution analysis targeted the soil-crop system in the sampling area,59.259%soil of the vegetable area was categorized as priority protection I₁,29.630%was categorized as priority protection I₂;76.923%soil of the rice area was classified as priority protection I₁,23.077%was grouped as priority protection I2.It implied that the risk of Cd pollution in those agricultural land was relatively low,thus negligible.Then 11.111%soil of the vegetable area was categorized as security utilizationⅡ₁,meaning that there were risks of Cd pollution,but could be controlled.Among crop products,the Cd concentration in 92.308%rice and 88.889%leafy vegetables did not exceed national food safety limit value,and Cd contamination of research area crop was less.Research crop and different parts of crop displayed both variability and consistency to Cd in soil:edible parts of leafy vegetables has stronger enrichment ability than that of rice;rice roots has stronger enrichment ability than other parts of rice,but both crop product has the strongest enrichment ability to soil Ca Cl₂Cd and the weakest enrichment ability to total amount of Cd.It revealed that Ca Cl₂solution could extract Cd which could be easily enriched by crop product,total amount f Cd had limited impact on Cd enrichment of crop product.Meanwhile,soil Cd was prone to be accumulated in rice roots with a small quantity of Cd translocated to the upper parts.When constructing the Cd enrichment model of soil-crop system,it is found that the soil p H had greater influence on the fitting coefficient in soil-vegetable enrichment model,the soil p H,TOC,CEC and soil particle concentration could gradually improve the fitting coefficient,saying that soil physiochemical properties were susceptible to both the accumulation and translocation of Cd in soil-crop system.In the health risk assessment of leafy vegetables and rice Cd for adults and children,the THQ_veg-Cdof adults is 0.689,the THQ_rice-Cdof adults is 0.199,the THQ_veg-Cdof children is1.507,the of THQ_rice-Cdis 0.358.Among them,the THQ of children is larger than that of adults,implying that consuming leafy vegetables and rice from the sampling area would impose a greater non carcinogenic risk to children than to adults.;THQ_veg-Cdof children is greater than1,meaning that children are more vulnerable to the non-carcinogenic risk posed by consuming leafy vegetables from the sampling area;hence,should be paid more attention to it.