重金属地质高背景区及工业区农作物重金属健康风险评价——以重庆市梁平区现代农业示范区为例

以重庆市梁平区现代农业示范区内分别受重金属地质高背景影响及工业活动影响的玉米、水稻、红苕、莲藕、柚子为研究对象,探讨重金属地质高背景区及工业区农作物重金属元素差异性的健康风险问题。通过对比研究,得到以下认识:1)以As、Hg、Cd、Cu、Zn和Ni为研究对象,水稻中As、Hg及Cd的平均含量总是大于玉米中对应元素的平均含量,水稻中Cu、Zn及Ni的平均含量总是小于玉米中对应元素的平均含量。水稻、玉米对于不同的重金属元素具有不同的富集特征。2)农作物的重金属危害商与重金属浓度呈正比关系。横向对比发现,工业区植物玉米中As、Hg、Cd、Zn及Ni元素的危害商皆大于地质高背景区玉米中对应元素的危害商,为工业活动对土壤中重金属形态的影响所致。3)柚子的重金属危害商在全区普遍偏低。地质高背景区植物莲藕中As元素的危害商达到了2.08,具有显著的健康风险。4)不同重金属元素对总危害商的贡献率表明,As、Cu元素的贡献率是最高的,Cd元素对地质背景区总危害商的贡献率高于工业区,应引起对Cd米污染的重视。

Health Risk Assessment of Heavy Metals in Crops from Geological Background of High Heavy Metals and Industrial Suburb——Taking a Modern Agricultural Demonstration Zone of Liangping County as an Example

This study is a health risk assessment of heavy metals in crops from area of high geological background of heavy metals and industrial suburb. We chose corn, rice, sweet potato, lotus root and grapefruit from modern agricultural demonstration zone of Liang ping County as the study object. And sampling areas were mainly affected by the high geological background of heavy metals or industrial activities. By comparing, we got the following understanding, 1) regardless of industrial area or geological background area, contents of As, Hg and Cd in rice are always higher than those in maize. Contents of Cu, Zn, and Ni in maize are always higher than those in rice. Rice and maize have different enrichment characteristics for different heavy metals; 2) the hazard quotient of crops is proportional to the concentration of heavy metals. The hazard quotient of As, Hg, Cd, Zn, and Ni in maize is higher than that in the high background area, due to the influence of industrial activities on the forms of heavy metals in soil; 3) the hazard quotient of grapefruit is generally low and the hazard quotient of As element of lotus root reaches 2.08 for high geological background area, with significant health risk; and 4) the contribution rate of heavy metal elements to the total hazard quotient shows that the contribution rate of As and Cu to the whole area is the highest. The contribution rate of Cd to geological background area is higher than that to industrial area. We should pay enough attention to the pollution of Cd on rice.