摘要:
农田土壤重金属污染直接危及到生态安全、食品安全和人体健康。从源头上控制农田土壤重金属污染是农业可持续发展和保障农产品质量安全的首要措施。本文采用物质流分析法与情景分析法,以水稻(双季稻、单季稻)、小麦-玉米、蔬菜(叶菜、根菜和果菜)的产地农田生态系统为研究对象,研究农田土壤中重金属铜的输入途径(大气沉降、磷肥、有机肥以及灌溉水)和输出途径(籽粒/可食部位、秸秆/残余物以及地表排水),并通过文献查阅和采样分析建立数据库,在平衡分析基础上为了保障100年土壤铜累积不超过设定的情景水平,当土壤铜背景值含量分别增加50%,100% 和150% 时,推导出磷肥、有机肥以及灌溉水的重金属含量安全阈值,磷肥中铜含量应控制在65~175 mg·kg-1范围内;畜禽粪肥中铜含量应控制在35~95 mg·kg-1范围内。灌溉水质标准应控制在40~70μg·L-1范围内。这将为我国农产品产地安全管理和源头预防控制,保障我国农产品质量安全提供一定的技术指导作用。
关键词:
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重金属铜
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来源
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平衡
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农作物
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安全阈值
Abstract:
Heavy metal pollution of farmland soil directly threatens the ecological system,food safety and human health.Controlling the source of heavy metal pollution in farmland ecosystems is a priority to guarantee the quality and safety of agricultural products.Using material flow and scenario methods,both input pathways(atmospheric deposition,phosphate fertilizer,organic fertilizer and irrigation water) and output pathways(grain/edible part,straw/crop residue and surface drainage) were studied to track copper movement and accumulation in soils used for the crop production of rice,wheat-corn and vegetables.A database was created to quantify the input and output of copper in farmland.A safety threshold of the amounts of copper found in phosphate fertilizer,organic fertilizer and irrigation water was calculated based on balance analysis and 100-year guarantee for pollution free of copper with the scenario of 50%,100% and 150% increase of soil copper background value.The copper content in phosphate fertilizer should be less than 65~175 mg·kg-1,copper content in manure should be controlled within 35~95 mg·kg-1,the copper content in the irrigation water should be controlled within 40 70~μg·L-1.This manuscript provides a technical guidance for farmland management of the heavy metal copper and will help to protect the quality and safety of Chinese agricultural products.
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