Soil and Groundwater Contamination Survey and Countermeasure Technologies
| Category of Tchnology | Survey | Soil Gas Survey | |
| Media | Soil Gas | ||
| Contaminants |
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| Applied (Demonstrated) Substances | Volatile Chlorinated Organic Compounds | ||
| Scope | Concentration Range | Equivalent to 1ppbv in concentration | |
| Hydrogeological Conditions |
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| Chemical Soil Properties | |||
| Other Remarks | This is the technique to measure the VOCs etc. concentration of the soil gas by using the absorbent tube (composed of activated carbon). It can be high sensitivity because of the concentration by the tube. Also, it can get the result speedy by a portable gas chromatograph in the site. | ||
| Technology Description | Classification | ||
| Status |
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| Outline of Technology | The soil gas will be pulled from a bore hole (f20-30mm) dug in a site and volatile components in it can be concentrated into activated carbon filled in a glass tube. Volatile components released from a glass tube by heat will be analyzed with a portable gas chromatograph (PID). Therefore each component of soil gases can be detected with high sensitivity. All devices including gas chromatograph are mounted in a car. | ||
| Required Pre- and Post-treatment | |||
| Enhance Effectiveness through Combination | Linear survey method, to which the soil-gas method is applied, for surveying the plume containing contaminated groundwater and for searching the contaminant source. | ||
| Case History | The time required for sampling is almost the same as the time for that of detector tube, that is, from 5 to 10 minutes for sampling. The analysis with a portable gas chromatograph, which takes much time in the site, takes only 15-20 minutes, so 15 to 20 samples can be analyzed in a day. It is possible to detect pollutants 50-100m apart from the origin of contamination in the soil gas investigation. | ||
| Application Examples | This is popular as the useful technique to investigate the soil gas with any concentration. | ||
| Limitations | Whole investigation in site includes the analysis with a portable gas chromatograph (a detection of pollutants) and making a distribution may of pollutants. | ||
| Properties of Treated Soil |
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| Schematic Flow Process | 
Process of Collection and Concentration for Soil Gas |
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| Applicability | In Situ Applicability | Possible | |
| Ground Structures | Applicable even if Ground Structures are Present * | ||
| Required Excavation | The sampling hole is a meter deep and about 2-3 cm diameter. | ||
| Groundwater Extraction | None | ||
| Required Space | Space for soil gas sampling work and parking space for portable analysis vehicle. | ||
| Operational Time |
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| Installation Time | The sampling work is possible about 15-20 points per day. | ||
| Maintenance and Control Requirements |
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| Additional Remarks | * Drill cutter is necessary for concrete floor. | ||
| Secondary Impacts to Environment | Secondary Treatment Required? |
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| Effects on Living Environment | |||
| Additives |
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| Possibility of Contaminant Spreading | None | ||
| Secondary By-products |
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Soil Environment Management Division, Water Environment Department, Environmental Management Bureau, Ministry of Environment
Tel: +81-3-5521-8319
E-mail: MOE@env.go.jp
