山东芋主产区的重金属检测及影响因素分析

Heavy Metal Detection and Analysis of Influence Factors in Main Taro Production Areas of Shandong Province

对山东芋主产区的球茎、农田土壤和灌溉水进行重金属抽样检测,依据GB18406.1—2001,83份球茎样本的As、Hg和Pb含量均未超过限量标准,33份芋球茎样本的Cd含量超过限量标准0.05mg·kg-1,但超出量较小,最高仅为0.36mg·kg-1,超标样本的分布区域不集中。依据GB/T18407.1—2001,83份土壤样本中的Pb、Hg和As含量均未超过对应pH值的限量标准,6份土壤样本的Cd含量超过限量标准0.3mg·kg-1(pH<7.5),最高值为0.944mg·kg-1。31份灌溉水样的4种重金属含量均未超标。检测结果表明,山东芋主产区的农田未受到4种主要重金属的污染。相关性分析结果显示,芋球茎的Cd、Pb含量与土壤中Cd、Pb含量分别呈极显著或显著正相关,表明芋球茎积累的Cd、Pb主要来源于土壤。芋球茎的Cd含量与土壤pH值呈显著负相关,土壤Cd、As、Pb与有机质含量呈极显著或显著正相关,表明土壤pH值和有机质含量是影响重金属积累的重要因素。农药和化肥的施用等可能导致了山东部分地区土壤中Cd的积累。

In this study, sampling test of heavy metals of tuber [Colocasia esculenta （ L. ） Schott ], soil and water were performed in main production areas of Shandong Province. The results indicated that As, Hg and Pb contents of 83 tuber samples did not exceed the maximum limits of GB 18406.1--2001. Cd content of 33 samples with relatively even distribution exceeded the limit of 0.05 mg . kg-1 by a very small amount. The highest value of Cd content was 0.36 mg .kg-1. According to GB/T 18407.1--2001, the As, Hg, Pb content of 83 soil samples did not exceed the maximum limits, while the Cd content of 6 soil samples exceeded the limit of 0.3 mg. kg-1 （ pH 〈 7.5 ） with highest value 0.944 mg . kg-1. Four heavy metal contents of 31 water samples did not exceed the maximum limits. It referred that taro production areas in Shandong Province were not polluted by the above mentioned 4 heavy metals. Further analysis revealed that the Pb and Cd contents of tubers were very significantly or significantly correlated with the Pb and Cd contents of soil, indicating that Pb and Cd in tubers mainly come from soil. The Cd content of tubers had a very significant negative correlation with pH value of soil, and the Cd, As and Pb contents in soil were very significantly or significantly correlated with the organic substance content, which indicating that pH value and organic matter contents were the main factors influencing heavy metal accumulation. The usage of agricultural medicine and fertilizers might cause Cd accumulation in some areas of Shandong Province.