桂北某铅锌矿影响区土壤和柑橘中重金属含量及柑橘产业再优化研究

Concentrations of Heavy Metal Contents in Soil and Citrus, and Citrus Industry Optimization Near a Lead and Zinc Mine in Northern Guangxi

为了解桂北某铅锌矿影响区柑橘地土壤和柑橘中重金属含量状况并探究当地柑橘产业绿色发展模式,采集当地柑橘地土壤样品131个,柑橘类水果样品(橘子58个、金桔13个)共71个,用原子荧光形态分析仪(AFS-9700)、石墨炉原子吸收分光光谱仪(AA 700)和电感耦合等离子发射光谱仪(Optima 7000)测定优先控制污染物As、Pb和Cd的含量,并通过污染指数法评价重金属污染水平。结果显示,研究区域柑橘地土壤pH值的算术平均值为6.07,表现为弱酸性;土壤重金属As污染程度为安全水平,w(Pb)和w(Cd)分别达91.40和0.906 mg·kg^-1,Pb和Cd污染程度都属于重度污染水平;土壤综合污染指数为4.90,属于重度污染水平。铅锌矿影响区种植的柑橘类水果,橘子中As、Pb和Cd含量均远远低于GB 2762—2017《食品安全国家标准食品中污染物限量》限值,金桔中Cd含量均超过标准限值,显示金桔存在一定的健康风险。为发展健康绿色的柑橘产业,建议通过柑橘品种优化、种植结构优化和施肥模式优化等措施进行改善,也可通过植物萃取技术减少土壤中重金属含量。

To understand the content of heavy metals in citrus soil and citrus in a lead-zinc mine affected area in northern Guangxi and explore the green development model of the local citrus industry,131 samples of local citrus soil and 71 citrus fruit samples(58 oranges and 13 kumquats)were collected.The atomic fluorescence spectrometer(AFS-9700),graphite furnace atomic absorption spectrometry(AA 700)and inductively coupled plasma emission spectrometry(Optima 7000)were used to determine the content of the three priority control pollutants:As,Pb and Cd.The pollution index method was used to assess the level of heavy metal pollution.Results show that the arithmetic mean soil pH was 6.07 in the study area,indicating that the soil was weakly acidic.The soil heavy metal As pollution was on the safety level.The content of heavy metals Pb and Cd reached 91.40 and 0.906 mg·kg-1,respectively,classified as severe pollution levels.The soil comprehensive pollution index was 4.90,which was at a level of heavy pollution.For the citrus fruits grown in the lead-zinc mine affected area,the contents of As,Pb and Cd in oranges were far below the national standard limit.The content of Cd exceeded the standard limits in kumquats,indicating that kumquat had certain health risks.To develop a healthy and green citrus industry,it is suggested that measures such as citrus variety optimization,planting structure optimization and fertilization mode optimization should be taken and plant extraction technology be used to improve the soil quality.