| 引黄灌区不同尺度农田土壤重金属空间分布及污染评价：以银川市兴庆区为例 |
| 摘要点击 5285 全文点击 2053 投稿时间：2013-11-03 修订日期：2013-12-30 |
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| 中文关键词 重金属 地统计分析 空间变异性 单因子指数 内梅罗综合污染指数 |
| 英文关键词 heavy metal geostatistical analyses spatial variability single pollution index Nemerow pollution index |
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| 中文摘要 |
| 确定农田土壤重金属分布及其污染状况，对于评价农业生态环境质量、保障食品安全和人类健康都具有重要作用. 以宁夏引黄灌区农田土壤为研究对象，在10 m（L尺度）和1 m（M尺度）两种尺度上网格取样，共取耕层土样（0~20 cm）223个，利用经典统计和地统计相结合的方法对土壤铜（Cu）、锌（Zn）、铬（Cr）、镉（Cd）和铅（Pb）的空间变异性进行研究，并利用单因子指数（Pi）和内梅罗综合指数（P综）评价土壤重金属的污染程度. 结果表明，两种尺度下，Cu、Zn、Cr、Cd、Pb均属中等变异性，其变异系数（CV）顺序为：Cd > Pb > Cr > Zn > Cu. 地统计分析表明，L尺度下Cd和M尺度下Pb块金系数为100%，表现为纯块金效应，主要受随机因素影响，具较弱的空间相关性. 其它重金属元素在两种尺度下块金系数均小于25%，说明主要受结构性因素的影响，具有强烈的空间相关性. 结合Pi和P综值可知，两种尺度下除了Cu外，其它4种重金属元素出现轻度污染的样点数较多，表明研究区已出现重金属富集的趋势. |
| 英文摘要 |
| Determining spatial distributions and analyses contamination condition of soil heavy metals play an important role in evaluation of the quality of agricultural ecological environment and the protection of food safety and human health. Topsoil samples (0-20 cm) from 223 sites in farmland were collected at two scales of sampling grid (1 m×1 m, 10 m×10 m) in the Yellow River irrigation area of Ningxia. The objectives of this study were to investigate the spatial variability of total copper (Cu), total zinc (Zn), total chrome (Cr), total cadmium (Cd) and total lead (Pb) on the two sampling scales by the classical and geostatistical analyses. The single pollution index (Pi) and the Nemerow pollution index (P) were used to evaluate the soil heavy metal pollution. The classical statistical analyses showed that all soil heavy metals demonstrated moderate variability, the coefficient of variation (CV) changed in the following sequence: Cd > Pb > Cr > Zn > Cu. Geostatistical analyses showed that the nugget coefficient of Cd on the 10 m×10 m scale and Pb on the 1 m×1 m scale were 100% with pure nugget variograms, which showed weak variability affected by random factors. The nugget coefficient of the other indexes was less than 25%, which showed a strong variability affected by structural factors. The results combined with Pi and P indicated that most soil heavy metals have slight pollution except total copper, and in general there were the trend of heavy metal accumulation in the study area. |
