我国茶叶主产区有机肥重金属含量现状

Status of Heavy Metal in Organic Fertilizers in Main Tea Growing Regions of China

调查分析我国茶叶主产区有机肥重金属含量可以为有机肥的安全使用提供指导,从而保障茶园土壤和茶叶质量安全.对2017~2019年期间收集的茶园施用的有机肥样品中的重金属含量进行了分析,并对不同种类有机肥的施用风险进行了测算.结果表明,我国茶叶主产区有机肥中ω(As)、ω(Hg)、ω(Pb)、ω(Cd)、ω(Cr)、ω(Cu)、ω(Zn)和ω(Ni)的平均含量分别为4.60、0.22、27.1、0.78、27.9、58.3、250.1和16.3 mg·kg^(-1).依据NY/T 525-2021中的评价标准,采集的有机肥样品中As、Hg、Pb、Cd和Cr超标率分别为6.19%、1.33%、4.42%、4.42%和1.33%.从不同地区看,陕西、江苏、安徽、福建和广西的有机肥合格率100%,山东、浙江、湖北、四川、云南和广东的有机肥合格率在80%~90%,而江西茶园施用的有机肥合格率仅54.5%.从不同来源看,有机肥合格率在菜籽饼肥、大豆饼肥和猪粪肥中为100%,羊粪肥95.8%、牛粪肥91.7%、鸡粪肥90.7%、其它动物类有机肥87.2%、动植物混合源类有机肥82.4%、其它植物类有机肥65.2%、其它类有机肥63.6%.根据推荐施用量估算,施用猪粪肥、牛粪肥、鸡粪肥和羊粪肥的土壤重金属累积速率将远超施用菜籽饼肥和大豆饼肥,动物源有机肥是植物源有机肥平均累积速率的7~30倍.因此,茶园上施用有机肥,建议选用菜籽饼肥和大豆饼肥,另一方面,对风险较高地区应加强监测,以降低土壤和茶叶重金属累积风险.

To provide guidance for the safe use of organic fertilizers and improve soil quality and tea safety,it is necessary to conduct systematic analyses of the heavy metal content of organic fertilizers applied in the main tea producing areas of China.In this study,we analyzed the heavy metal contents in organic fertilizer samples collected from 2017 to 2019.The risks of collected organic fertilizers from different areas and sources were calculated.The results showed that the average concentrations ofω(As),ω(Hg),ω(Pb),ω(Cd),ω(Cr),ω(Cu),ω(Zn),andω(Ni)in the collected organic fertilizers were 4.60,0.22,27.1,0.78,27.9,58.3,250.1,and 16.3 mg·kg^(-1),respectively.According to the assessment standard in NY/T 525-2021,the over-limit rates of As,Hg,Pb,Cd,and Cr were 6.19%,1.33%,4.42%,4.42%,and 1.33%,respectively.With respect to the area,the qualified rates were 100%in Shaanxi,Jiangsu,Anhui,Fujian,and Guangxi;80%-90%in Shandong,Zhejiang,Hubei,Sichuan,Yunnan,and Guangdong;and only 54.5%in Jiangxi.The qualified rates of sources were 100%in rapeseed cake,soybean cake,and pig manure;95.8%in sheep manure;91.7%in cow manure;90.7%in chicken manure;87.2%in manure of other animals;82.4%in the mixture of plant and animal sources;65.2%in other plant sources;and 63.6%in other sources.According to the recommended application rate,the accumulation rate of heavy metals in soil with pig manure,cow manure,chicken manure,and sheep manure would be much higher than that with rapeseed cake and soybean cake.The average accumulation rate of organic fertilizer from animal sources was 7-30 times higher than that from plant sources.Therefore,it is recommended to use rapeseed cake or soybean cake fertilizer in tea plantation and to increase the supervision of heavy metal accumulation in soil and tea in those high-risk areas.