Faculty of Agriculture Food and Natural Resources, The University of Sydney, Sydney, NSW 2006, Australia.
Environ Sci Technol. 2011 Dec 15;45(24):10463-70. doi: 10.1021/es201726c. Epub 2011 Nov 29.
This study investigated the spatial variability of total and phosphate-extractable arsenic (As) concentrations in soil adjacent to a cattle-dip site, employing a linear mixed model-based geostatistical approach. The soil samples in the study area (n = 102 in 8.1 m(2)) were taken at the nodes of a 0.30 × 0.35 m grid. The results showed that total As concentration (0-0.2 m depth) and phosphate-extractable As concentration (at depths of 0-0.2, 0.2-0.4, and 0.4-0.6 m) in soil adjacent to the dip varied greatly. Both total and phosphate-extractable soil As concentrations significantly (p = 0.004-0.048) increased toward the cattle-dip. Using the linear mixed model, we suggest that 5 samples are sufficient to assess a dip site for soil (As) contamination (95% confidence interval of ±475.9 mg kg(-1)), but 15 samples (95% confidence interval of ±212.3 mg kg(-1)) is desirable baseline when the ultimate goal is to evaluate the effects of phytoremediation. Such guidelines on sampling requirements are crucial for the assessment of As contamination levels at other cattle-dip sites, and to determine the effect of phytoremediation on soil As.
本研究采用基于线性混合模型的地统计学方法，研究了牛场浸浴区附近土壤中总砷和磷酸盐提取态砷浓度的空间变异性。研究区（8.1m2 内共 102 个样本）的土壤样本取自 0.30×0.35m 网格的节点上。结果表明，牛场浸浴区附近土壤中总砷浓度（0-0.2m 深度）和磷酸盐提取态砷浓度（0-0.2m、0.2-0.4m 和 0.4-0.6m 深度）差异较大。总砷和磷酸盐提取态土壤砷浓度均显著（p=0.004-0.048）向牛场浸浴区增加。通过线性混合模型，我们建议 5 个样本足以评估浸浴区的土壤（砷）污染（95%置信区间为±475.9mgkg-1），但如果最终目标是评估植物修复的效果，则需要 15 个样本（95%置信区间为±212.3mgkg-1）作为基线。这些采样要求的指南对于评估其他牛场浸浴区的砷污染水平以及确定植物修复对土壤砷的影响至关重要。
