Learn about the best remediation techniques for vapor intrusion, the migration of volatile chemicals from contaminated soil or groundwater into indoor air.

Excavating soil contaminated with VOCs will put operatives at risk and COSHH risk assessment must be undertaken to control exposure. Although work is undertaken outdoors, liberating trapped patches of organic chemical within the soil can result in peak VOC exposure above STEL or Ceiling limits. Real-time personal exposure monitors is an essential tool for ground operative during contaminated soil excavation.

What are the most effective remediation techniques for vapor intrusion?

Vapor intrusion (VI) is the migration of volatile chemicals from contaminated soil or groundwater into indoor air of buildings. It can pose health and safety risks for occupants and reduce property values. Therefore, it is important to identify and remediate VI sources and pathways as part of environmental site assessment and cleanup. In this article, you will learn about some of the most effective remediation techniques for VI and their advantages and disadvantages.

1 Soil Vapor Extraction

Soil vapor extraction (SVE) is a remediation technique that involves applying a vacuum to the soil to extract the contaminated vapors and treat them before discharge. SVE can reduce the mass and concentration of volatile organic compounds (VOCs) in the soil and lower the potential for VI. However, SVE may not be effective in low-permeability soils, high-moisture conditions, or deep contamination zones. SVE also requires regular monitoring and maintenance of the extraction wells and treatment system.

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Debashree Dutta

Sustainability || ESG || Environment || Strategies & Reporting Advisor & Consultant || Agile Leader💡|| Passionate about driving the balance and make a difference to create a sustainable future for everyone
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The choice of remediation technique depends on site-specific factors, including contaminant type, concentration, and building characteristics. Sub-Slab Depressurization (SSD): Installing a ventilation system beneath the building's slab to create negative pressure, preventing vapors from entering. Soil Vapor Extraction (SVE): Removing vapor-contaminated air from the soil using extraction wells and treating it before release. Air Sparging: Injecting air or oxygen into contaminated groundwater to enhance biodegradation and reduce vapor emissions. Active and Passive Ventilation: Installing mechanical ventilation systems to remove indoor air and dilute contaminant concentrations.

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2 Sub-Slab Depressurization

Sub-slab depressurization (SSD) is a remediation technique that involves creating a negative pressure zone under the building slab to prevent the upward migration of contaminated vapors into indoor air. SSD can be achieved by installing a fan and piping system that draws air from beneath the slab and vents it to the outdoor air. SSD can be effective in reducing VI exposure and can be customized to suit different building types and sizes. However, SSD may not address the source of contamination and may increase energy costs and noise levels.

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Joseph Rizzi

President of Natural Desalination
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Spray on rubberize sealer. Easy to apply to uneven surface to seal it off. Second coat may be needed in some case of problem surfaces. After cured, can be inspected for bubbles for high release spots, to be plugged.

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3 Vapor Barriers and Sealing

Vapor barriers and sealing are remediation techniques that involve installing impermeable materials or coatings on the building slab, foundation, or walls to block or reduce the diffusion of contaminated vapors into indoor air. Vapor barriers and sealing can be used as preventive measures or in combination with other remediation techniques. However, vapor barriers and sealing may not be sufficient to eliminate VI risk and may require periodic inspection and repair to ensure their integrity and performance.

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4 Enhanced Biodegradation

Enhanced biodegradation is a remediation technique that involves stimulating the natural breakdown of contaminants by microorganisms in the soil or groundwater. Enhanced biodegradation can be achieved by injecting oxygen, nutrients, or other amendments into the subsurface to enhance the microbial activity and degradation rate. Enhanced biodegradation can reduce the source and extent of contamination and lower the potential for VI. However, enhanced biodegradation may not be applicable to all contaminants and may require careful site characterization and monitoring to optimize the biodegradation process.

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5 Air Purification and Ventilation

Air purification and ventilation are remediation techniques that involve improving the indoor air quality by removing or diluting the contaminated vapors. Air purification can be achieved by using filters, adsorbents, or oxidizers to capture or destroy the VOCs in the indoor air. Ventilation can be achieved by increasing the outdoor air supply or exhaust to create a positive pressure or air exchange in the building. Air purification and ventilation can be effective in reducing VI exposure and improving occupant comfort and health. However, air purification and ventilation may not address the source of contamination and may increase energy consumption and operating costs.

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6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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Jans Babkevičs

Your Weekly Dose of Occupational Hygiene 🧠 #BitesizeOH 🔔 Chartered Occupational Hygienist 🕵🏻 Educational Content Creator 💡
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Excavating soil contaminated with VOCs will put operatives at risk and COSHH risk assessment must be undertaken to control exposure. Although work is undertaken outdoors, liberating trapped patches of organic chemical within the soil can result in peak VOC exposure above STEL or Ceiling limits. Real-time personal exposure monitors is an essential tool for ground operative during contaminated soil excavation.

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What are the most effective remediation techniques for vapor intrusion?

1

2

3

4

5

6

1 Soil Vapor Extraction

2 Sub-Slab Depressurization

3 Vapor Barriers and Sealing

4 Enhanced Biodegradation

5 Air Purification and Ventilation

6 Here’s what else to consider

Environmental Services

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What are the most effective remediation techniques for vapor intrusion?

1

2

3

4

5

6

1 Soil Vapor Extraction

2 Sub-Slab Depressurization

3 Vapor Barriers and Sealing

4 Enhanced Biodegradation

5 Air Purification and Ventilation

6 Here’s what else to consider

Environmental Services

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