果园土壤和水果中重金属含量及相关性分析

Analysis of heavy metals content and correlation in orchard soils and fruits

目的了解雅安特色水果主产区果园土壤和水果中重金属含量及污染程度,分析其相关性。方法以雅安水果主产区汉源县3种水果及产地果园土壤为研究对象,采集了甜樱桃、苹果、黄果柑各30份,产地果园内土壤各30份以湿法消解原子荧光和原子吸收检测汞(Hg)、砷(As)、铅(Pb)、镉(Cd)、铬(Cr)和铜(Cu)6种重金属,对3种水果中重金属是否超过限量值进行了污染评价;用积累指数法、内梅罗指数和单因子污染指数对土壤中重金属污染程度进行了评价;分析了6种重金属与pH相互间的关联性及水果对重金属的富集特性。结果3种水果及其果园土壤中重金属含量总体呈现黄果柑>苹果>甜樱桃,黄果柑中有2个样品Pb含量超出限量值,其他重金属在水果和土壤中均未超标。3种水果土壤单因子(P_(i))和综合污染指数(P_(N))均小于0.7,为清洁无污染土壤。黄果柑土壤中6种重金属都与pH成正相关,甜樱桃和苹果中重金属除Cr外都与pH成负相关;3种水果与其同位点土壤中6种重金属均没有显著相关性;Cd-Pb-Hg-Cu 4种元素间在0.01水平上显著相关,4者具有同源关系;3种水果中黄果柑对Cu、甜樱桃和苹果对Hg的富集最强。结论3种水果重金属基本都在限量值内,属于安全品质水果;果园土壤的重金属个别超过了限量值,但平均值均未超过限量值,总体安全。从单因素和综合因素考虑都属清洁型土壤,适合这3种水果的种植和生长。水果中重金属含量与同位点土壤的的重金属含量、pH等存在一定的相关性。

Objective To understand the content and pollution level of heavy metals in orchard soils and fruits in the main production area of Ya’an characteristic fruits,and understand the correlation between their heavy metals.Methods Three kinds of fruits and orchard soils of originating from Hanyuan County,the main fruit production area of Ya’an,were used as research objects.The 30 samples each of sweet cherry,apple and yellow fruit citrus were collected,and 30 samples each of orchard soils of origin were detected by wet ablation atomic fluorescence and atomic absorption for 6 kinds of heavy metals of Hg,As,Pb,Cd,Cr and Cu,and whether the heavy metals in 3 kinds of fruits exceeded the degree of heavy metal contamination in the soil was evaluated by the accumulation index method,the Nemerow index and the single factor contamination index.The correlation between the 6 kinds of heavy metals and pH and the enrichment of heavy metals in fruits were analysed.Results The total content of heavy metals in 3 kinds of fruits and their orchard soils showed yellow citrus>apple>sweet cherry,Pb content in 2 samples of Huangguogang exceeded the limit value,all other heavy metals in fruits and soils did not exceed the limits.The single factor(P_(i))and comprehensive pollution index(P_(N))of 3 kinds of fruit soil were less than 0.7,indicating that the soil was clean and pollution-free.All 6 kinds of heavy metals in the soils of yellow fruit citrus were positively correlated with pH,sweet cherry and apple were negatively correlated with pH except for Cr.There was no significant correlation between 6 kinds of heavy metals in the soil of 3 kinds of fruit and their co-location;the 4 kinds of elements of Cd-Pb-Hg-Cu were significantly correlated at the 0.01 level,and the four were homologous;pH led to the negative correlation of Hg with As and Cr,and 3 kinds of fruits of yellow fruit citrus to Cu,sweet cherry and apple had the strongest enrichment of Hg.Conclusion In addition to the fruit Pb exceeded the limit,heavy metals are within the limit,belong to the safe quality of fruit;orchard soil heavy metals individually exceeds the limit,but the average value do not exceed the limit,the overall safety.Considering from single factor and comprehensive factor,it belongs to clean soil,which is suitable for the planting and growth of these 3 kinds of fruits.There is a certain correlation between the heavy metal content in fruit and the heavy metal content and pH of soil at the same site.