U.S. Geological Survey, Missouri Water Science Center, 1400 Independence Road, Rolla, Missouri 65401, United States.
Department of Civil, Environmental, and Architectural Engineering, Missouri University of Science and Technology , 1201 North State Street, Rolla, Missouri 65409, United States.
Environ Sci Technol. 2017 Sep 19;51(18):10369-10378. doi: 10.1021/acs.est.7b02667. Epub 2017 Aug 31.
Vapor intrusion (VI) by volatile organic compounds (VOCs) in the built environment presents a threat to human health. Traditional VI assessments are often time-, cost-, and labor-intensive; whereas traditional subsurface methods sample a relatively small volume in the subsurface and are difficult to collect within and near structures. Trees could provide a similar subsurface sample where roots act as the "sampler' and are already onsite. Regression models were developed to assess the relation between PCE concentrations in over 500 tree-core samples with PCE concentrations in over 50 groundwater and 1000 soil samples collected from a tetrachloroethylene- (PCE-) contaminated Superfund site and analyzed using gas chromatography. Results indicate that in planta concentrations are significantly and positively related to PCE concentrations in groundwater samples collected at depths less than 20 m (adjusted R values greater than 0.80) and in soil samples (adjusted R values greater than 0.90). Results indicate that a 30 cm diameter tree characterizes soil concentrations at depths less than 6 m over an area of 700-1600 m, the volume of a typical basement. These findings indicate that tree sampling may be an appropriate method to detect contamination at shallow depths at sites with VI.
在建筑环境中，挥发性有机化合物 (VOC) 的蒸气侵入 (VI) 对人类健康构成威胁。传统的 VI 评估通常耗时、耗力且成本高昂；而传统的地下方法仅在地下小范围内采样，并且难以在建筑物内部和附近进行采样。树木可以提供类似的地下样本，其根系充当“采样器”，并且已经在现场。我们建立了回归模型来评估 500 多个树木芯样本中的 PCE 浓度与从一个四氯乙烯 (PCE) 污染的超级基金场地采集的超过 50 个地下水样本和 1000 个土壤样本中的 PCE 浓度之间的关系，这些样本使用气相色谱法进行了分析。结果表明，在植物体内的浓度与深度小于 20 米的地下水样本中的 PCE 浓度（调整后的 R 值大于 0.80）和土壤样本中的 PCE 浓度（调整后的 R 值大于 0.90）呈显著正相关。结果表明，一棵 30 厘米直径的树可以在 VI 场地的浅深度处，对面积为 700-1600 平方米的区域内深度小于 6 米的土壤浓度进行特征描述。这些发现表明，在存在 VI 的场地中，树木采样可能是一种检测浅层污染的合适方法。
