Agronomy Department, Federal University of Sergipe, São Cristóvão, Brazil.
Int J Phytoremediation. 2012 Dec;14(10):939-49. doi: 10.1080/15226514.2011.636404.
Using chemical extraction to evaluate plant arsenic availability in contaminated soils is important to estimate the time frame for site cleanup during phytoremediation. It is also of great value to assess As mobility in soil and its risk in environmental contamination. In this study, four conventional chemical extraction methods (water, ammonium sulfate, ammonium phosphate, and Mehlich III) and a new root-exudate based method were used to evaluate As extractability and to correlate it with As accumulation in P. vittata growing in five As-contaminated soils under greenhouse condition. The relationship between different soil properties, and As extractability and plant As accumulation was also investigated. Arsenic extractability was 4.6%, 7.0%, 18%, 21%, and 46% for water, ammonium sulfate, organic acids, ammonium phosphate, and Mehlich III, respectively. Root exudate (organic acids) solution was suitable for assessing As bioavailability (81%) in the soils while Mehlich III (31%) overestimated the amount of As taken up by plants. Soil organic matter, P and Mg concentrations were positively correlated to plant As accumulation whereas Ca concentration was negatively correlated. Further investigation is needed on the effect of Ca and Mg on As uptake by P. vittata. Moreover, additional As contaminated soils with different properties should be tested.
采用化学提取法评估污染土壤中植物砷的有效性，对于估算植物修复过程中的场地清理时间框架至关重要。这对于评估土壤中砷的迁移性及其对环境污染的风险也具有重要意义。在本研究中，采用了四种常规化学提取方法（水、硫酸铵、磷酸铵和 Mehlich III）和一种新的基于根分泌物的方法，以评估砷的可提取性，并将其与在温室条件下生长于五处砷污染土壤中的蜈蚣草对砷的积累进行相关性分析。还研究了不同土壤性质与砷可提取性和植物砷积累之间的关系。水、硫酸铵、有机酸、磷酸铵和 Mehlich III 提取的砷分别占 4.6%、7.0%、18%、21%和 46%。根分泌物（有机酸）溶液适合评估土壤中砷的生物有效性（81%），而 Mehlich III（31%）高估了植物吸收的砷量。土壤有机质、磷和镁浓度与植物砷积累呈正相关，而钙浓度则呈负相关。需要进一步研究钙和镁对蜈蚣草吸收砷的影响。此外，还应测试具有不同性质的其他砷污染土壤。
