Geosyntec Consultants, Inc., 130 Research Lane, #2, Guelph, N1G 5G3, Ontario, Canada.
Environ Sci Process Impacts. 2014 Mar;16(3):501-10. doi: 10.1039/c3em00653k. Epub 2014 Feb 11.
Volatile organic compounds (VOCs) are commonly associated with contaminated land and may pose a risk to human health via subsurface vapor intrusion to indoor air. Soil vapor sampling is commonly used to assess the nature and extent of VOC contamination, but can be complicated because of the wide range of geologic material permeability and moisture content conditions that might be encountered, the wide variety of available sampling and analysis methods, and several potential causes of bias and variability, including leaks of atmospheric air, adsorption-desorption interactions, inconsistent sampling protocols and varying levels of experience among sampling personnel. Passive sampling onto adsorbent materials has been available as an alternative to conventional whole-gas sample collection for decades, but relationships between the mass sorbed with time and the soil vapor concentration have not been quantitatively established and the relative merits of various commercially available passive samplers for soil vapor concentration measurement is unknown. This paper presents the results of field experiments using several different passive samplers under a wide range of conditions. The results show that properly designed and deployed quantitative passive soil vapor samplers can be used to measure soil vapor concentrations with accuracy and precision comparable to conventional active soil vapor sampling (relative concentrations within a factor of 2 and RSD comparable to active sampling) where the uptake rate is low enough to minimize starvation and the exposure duration is not excessive for weakly retained compounds.
挥发性有机化合物（VOCs）通常与污染土地有关，可能通过地下蒸气侵入室内空气对人类健康构成威胁。土壤蒸气采样通常用于评估 VOC 污染的性质和程度，但由于可能遇到的地质材料渗透率和含水量条件范围广泛、各种可用的采样和分析方法以及包括大气空气泄漏、吸附-解吸相互作用、不一致的采样协议和采样人员之间不同水平的经验等几种潜在的偏差和可变性原因，采样可能会变得复杂。几十年来，吸附剂材料上的被动采样一直是传统全气体采集的替代方法，但吸附时间与土壤蒸气浓度之间的关系尚未得到定量确定，并且各种市售的被动采样器在测量土壤蒸气浓度方面的相对优点也尚不清楚。本文介绍了在广泛条件下使用几种不同的被动采样器进行现场实验的结果。结果表明，设计和部署得当的定量被动土壤蒸气采样器可用于以与传统主动土壤蒸气采样相当的准确度和精密度测量土壤蒸气浓度（相对浓度在 2 倍以内，与主动采样相当的 RSD），只要吸收速率足够低以最小化饥饿，并且暴露时间对于弱保留化合物来说不是过长。
