| 污染场地土壤气被动采样技术研究进展 |
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| 引用本文： | 马杰.污染场地土壤气被动采样技术研究进展[J].环境科学研究,2020,33(2):494-502. |
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| 作者姓名： | 马杰 |
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| 作者单位： | 1.中国石油大学(北京)化学工程与环境学院, 北京 102249 |
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| 基金项目： | 国家自然科学基金项目（No.21407180，21878332）；北京市科技新星计划项目（No.Z181100006218088） |
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| 摘 要： | 在VOCs（挥发性有机物）污染场地调查中，土壤气采样的重要性日益受到重视.常规的土壤气采样主要依赖吸附管和采样罐等主动采样方法，但主动采样有很多缺点.作为一种新兴的采样技术，被动采样具有成本低、操作简单、更能代表长时间人体暴露、可用于低渗透性地层等优点，已经成为污染场地调查领域的研究热点.对被动采样的理论基础、采样器类型、吸附剂类型、采样误差的来源进行了介绍，对土壤气被动采样中存在的技术难题以及前沿研究方向进行了讨论，并对该技术在我国场地调查领域的应用前景进行了展望和建议.结果表明:在被动采样中准确控制采样器的采样速率（uptake rate）是保证其定量能力的关键，当控制采样速率低于土壤气中VOCs的补给速率时，可以实现良好的定量效果.影响采样速率的主要因素包括待测VOCs的性质、吸附剂种类、采样器结构以及各类环境因素，挥发性强的VOCs较难被捕集且容易发生逃逸.不同被动采样器用于不同种类VOCs采样时的采样速率可以相差6个数量级，从最低的0.005 5 mL/min到最高的125 mL/min.因此，建议在实际采样中应选用结构合理的采样器，控制采样速率不宜过大，以降低饥饿效应的产生；应选用与待测物匹配的吸附剂，对待测物兼具良好的保留能力和脱附能力；应加强环境因素（温度、湿度、土壤性质）对采样速率影响机制及场地校准方法的研究；应该结合研究和实践经验制定符合我国国情的土壤气被动采样技术指南.
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| 关 键 词： | 污染场地 土壤污染 土壤修复 场地调查 风险评估 挥发性有机物 被动采样 土壤气 |
| 收稿时间： | 2019/6/30 0:00:00 |
| 修稿时间： | 2019/9/5 0:00:00 |
Research Progress on Soil Gas Passive Sampling Technology at Contaminated Sites |
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| MA Jie.Research Progress on Soil Gas Passive Sampling Technology at Contaminated Sites[J].Research of Environmental Sciences,2020,33(2):494-502. |
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| Authors: | MA Jie |
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| Affiliation: | 1.China University of Petroleum-Beijing, College of Chemical Engineering and Environment, Beijing 102249, China2.State Key Laboratory of Heavy Oil Processing, Beijing 102249, China3.Beijing Key Lab of Oil & Gas Pollution Control, Beijing 102249, China |
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| Abstract: | Soil gas data is increasingly regarded as an important evidence for the site investigation and risk assessment of industrial sites impacted by volatile organic compounds (VOCs). Conventional soil gas sampling methods rely on active sampling, such as sorbent tube and canister, but these methods have some limitations. Passive sampling is a promising method for soil gas sampling, which has several advantages, such as low cost, easy implementation, more representative for the long-term human exposure, and applicable for the low permeable aquifer. Therefore, passive soil gas sampling has become a hot research topic in the area of site investigation and risk assessment. This paper introduces the theoretical basis, samplers, sorbents, and sampling errors associated with passive soil gas sampling. Current technical challenges and research frontiers as well as future application of soil gas passive sampling techniques in China are discussed. It is found that the uptake rate is the key to the accurate quantification of soil gas concentration during passive sampling. Keeping the uptake rate lower than the transport rate from the surrounding soil is the key to the success of quantitative measurements. The key factors that affect the uptake rate include VOCs, sampler structure, sorbents and various environmental factors. Highly volatile VOCs are more difficult to be captured and more likely to escape from samplers via back diffusion. The uptake rate of different VOCs by different passive samplers would vary up to 6 orders of magnitudes from 0.0055 mL/min to 125 mL/min. Appropriate samplers should have low uptake rate to minimize starvation effect. In summary, appropriate sorbent should be excellent in both adsorption and desorption for the target VOCs. More researches are needed to improve current understanding of influence of environmental factors (temperature, humidity, and soil properties) on uptake rate as well as field calibration method. Based on laboratory research and field experiences, a guidance for passive soil gas sampling that is suitable for China needs to be established. |
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| Keywords: | contaminated site soil contamination soil remediation site investigation risk assessment volatile organic compounds passive sampling soil gas |
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