荸荠地土壤中铅和镉的测定及污染评价

唐昭领　包秘　左柱敏　赵大庆　陈蔚　陶剑恒　李惠静　罗晓慧　莫秋云　王蕾

摘要 [目的]利用微波消解-石墨炉原子吸收光谱法测定荸荠地土壤中铅和镉含量，验证检测方法的检出限、准确度与精密度，分析荸荠土壤中重金属铅和镉含量。[方法]采用单因子污染指数法和潜在生态危害指数法对研究区荸荠地土壤中铅和镉的污染及其生态风险进行评价。[结果]荸荠地土壤中铅含量为10.1～25.8 mg/kg，平均值为21.9 mg/kg；镉含量为0.154 ～0.280 mg/kg，平均值为0.198 mg/kg。以食用农产品产地环境质量标准为评价依据，铅和镉含量均处于无污染的清洁水平。2种重金属其潜在生态危害强度镉大于铅，均处于轻微的潜在生态风险水平。[结论]研究区荸荠地土壤中铅和镉污染风险程度较低。

关键词 荸荠土壤；石墨炉原子吸收光谱法；铅；镉；污染评价

中图分类号 S158.4 文献标识码

A 文章编号 0517-6611（2018）18-0102-03

Determination and Pollution Evaluation of Lead and Cadmium in Water Chestnut Soil

TANG Zhaoling，BAO Mi，ZUO Zhumin et al （Hezhou Institutes for Food and Drug Control，Hezhou， Guangxi 542800）

Abstract [Objective] Microwave digestiongraphite furnace atomic absorption spectrometry method was used to determine the concentrations of Pb and Cd in water chestnut soil.The detection limitation，accuracy and precision of the method were validated，the content of Pb and Cd was analyzed.[Method] The pollution degree and ecological risk of Pb and Cd of the studied water chestnut soil were analyzed by means of single pollution index and potential ecological risk index.[Result] The range of Pb concentration soils was between 10.1 mg/kg and 25.8 mg/kg，the average concentration was 21.9 mg/kg，the range of Cd concentration in soils was between 0.154 mg/kg and 0.280 mg/kg，the average concentration was 0.198 mg/kg.Based on the environmental quality standard of soils for edible agricultural products，Pb and Cd concentration in soil was at clean level.Moreover，the results of potential ecological risk index showed that the potential ecological risk degree of Pb and Cd was characterized by order of Cd>Pb，the potential ecological risk of Pb and Cd was at slightly level.[Conclusion] On the whole，the pollution risk degree of Pb and Cd in water chestnut area soil is low.

Key words Water chestnut soil；Graphite furnace atomic absorption spectrometry；Lead；Cadmium；Pollution evaluation

土壤重金屬含量是绿色食品产地环境监测中的一项重要指标[1]。当重金属积累到一定程度会对植物生长土壤造成污染，进而影响植物的生长发育和果实品质，再通过食物链使人体产生多种疾病，危害人体生命和健康[2]，在这些重金属中，铅和镉尤为突出，毒性最大。因此，农田土壤中铅和镉含量测定与安全性评价引起了人们的广泛关注[3-4]。近年来，国内荸荠种植面积不断扩大，其荸荠产业得到了极大发展，但随着工业化的不断发展，荸荠生产中使用了大量的农药和化肥，使得荸荠地土壤污染日益严重，也给荸荠的质量安全带来严重威胁，但截至目前，关于荸荠地土壤中铅和镉的研究鲜见报道。

铅和镉的检测分析方法很多，主要有原子荧光光谱法[5]、电感耦合等离子体质谱法[6]、电化学法[7]、原子吸收光谱法[8]、X射线荧光光谱法[9] 等。在参考有关文献的基础上，笔者利用石墨炉原子吸收光谱法测定荸荠地土壤中铅和镉含量，并对检测方法的准确度与精密度进行了验证，根据测定结果对荸荠地土壤中铅和镉的含量进行分析，分别以食用农产品产地环境质量标准和广西地区土壤背景值为评价依据，采用单因子污染指数法和潜在生态危害指数法对研究区荸荠地土壤中铅和镉的污染及其生态风险进行评价，以期为荸荠产地环境中铅和镉的污染防控提供理论依据。

1 材料与方法

1.1 材料与仪器