荸薺地土壤中鉛和鎘的測定及污染評價

唐昭領　包秘　左柱敏　趙大慶　陳蔚　陶劍恒　李惠靜　羅曉慧　莫秋云　王蕾

摘要 [目的]利用微波消解-石墨爐原子吸收光譜法測定荸薺地土壤中鉛和鎘含量，驗證檢測方法的檢出限、準確度與精密度，分析荸薺土壤中重金屬鉛和鎘含量。[方法]采用單因子污染指數法和潛在生態(tài)危害指數法對研究區(qū)荸薺地土壤中鉛和鎘的污染及其生態(tài)風險進行評價。[結果]荸薺地土壤中鉛含量為10.1～25.8 mg/kg，平均值為21.9 mg/kg；鎘含量為0.154 ～0.280 mg/kg，平均值為0.198 mg/kg。以食用農產品產地環(huán)境質量標準為評價依據，鉛和鎘含量均處于無污染的清潔水平。2種重金屬其潛在生態(tài)危害強度鎘大于鉛，均處于輕微的潛在生態(tài)風險水平。[結論]研究區(qū)荸薺地土壤中鉛和鎘污染風險程度較低。

關鍵詞 荸薺土壤；石墨爐原子吸收光譜法；鉛；鎘；污染評價

中圖分類號 S158.4 文獻標識碼

A 文章編號 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

土壤重金屬含量是綠色食品產地環(huán)境監(jiān)測中的一項重要指標[1]。當重金屬積累到一定程度會對植物生長土壤造成污染，進而影響植物的生長發(fā)育和果實品質，再通過食物鏈使人體產生多種疾病，危害人體生命和健康[2]，在這些重金屬中，鉛和鎘尤為突出，毒性最大。因此，農田土壤中鉛和鎘含量測定與安全性評價引起了人們的廣泛關注[3-4]。近年來，國內荸薺種植面積不斷擴大，其荸薺產業(yè)得到了極大發(fā)展，但隨著工業(yè)化的不斷發(fā)展，荸薺生產中使用了大量的農藥和化肥，使得荸薺地土壤污染日益嚴重，也給荸薺的質量安全帶來嚴重威脅，但截至目前，關于荸薺地土壤中鉛和鎘的研究鮮見報道。

鉛和鎘的檢測分析方法很多，主要有原子熒光光譜法[5]、電感耦合等離子體質譜法[6]、電化學法[7]、原子吸收光譜法[8]、X射線熒光光譜法[9] 等。在參考有關文獻的基礎上，筆者利用石墨爐原子吸收光譜法測定荸薺地土壤中鉛和鎘含量，并對檢測方法的準確度與精密度進行了驗證，根據測定結果對荸薺地土壤中鉛和鎘的含量進行分析，分別以食用農產品產地環(huán)境質量標準和廣西地區(qū)土壤背景值為評價依據，采用單因子污染指數法和潛在生態(tài)危害指數法對研究區(qū)荸薺地土壤中鉛和鎘的污染及其生態(tài)風險進行評價，以期為荸薺產地環(huán)境中鉛和鎘的污染防控提供理論依據。

1 材料與方法

1.1 材料與儀器