© 2008, By J.G. Pohl, Principal, Integral Environmental Solutions (IES), Australia

Sydney groundwater wells or bores have revealed the effects of decades of industrial contamination in the groundwater below Sydney's eastern suburbs.

Can contaminated groundwater affect my family’s or employees health?
Yes. A lesser known way that your family’s or employees health can be impacted is by the intrusion of colourless, odourless vapours that migrate into your home or offices living / work spaces from contaminated subsurface soil and groundwater. This effect of indoor air contamination is called vapour intrusion In the US, the Environmental Protection Agency (EPA) has targeted this source of indoor pollution due to the insidious nature of this silent killer.

What is Vapour Intrusion?
Vapour intrusion is the migration of volatile chemicals from the subsurface into overlying buildings. Volatile chemicals in buried wastes and/or contaminated groundwater can emit vapours that may migrate through subsurface solid and into overlying building airspaces. In most cases, the chemical concentrations are low, or depending on site-specific conditions, vapours may not be present at detectable concentrations.
In some cases, sampling near a known subsurface accumulation of vapours has identified indoor air impacts requiring action, and, in other cases, vapour sampling has been completed following an odour complaint in order to trace the source and identify appropriate mitigation measures. Each site is unique and no one approach is appropriate for all.

Health and Safety Concerns with Vapour Intrusion
- Indoor vapours may accumulate in occupied buildings to unhealthy levels
- Acute health effects
- Indoor odour problems
- Possible fire safety hazard
Vapour Intrusion Fact Sheet from US EPA
NSW Natural Resources - Water Quality in Eastern Suburbs
Causes of Vapour Intrusion
- Imperfect building construction
- Ventilation problems
- Heating / cooling system configuration
- Utility conduit entrances,
- Indoor air advection or diffusion
- Soil type
- Volatilisation of subsurface organic contaminants
in the vicinity of a building

How do I find out if I have a Vapour Intrusion Problem?
We at IES provide expert consulting services in all aspects of Vapour Intrusion issues by helping our clients find practical and defensible solutions to resolve disputes, achieve regulatory compliance, and protect and improve environmental quality. At IES, we can provide you with the following services related to Vapour Intrusion:

- Field Assessment & Analysis
- Vapour Intrusion Management Plans
- Engineering Controls
- Vapour Intrusion Rehabilitation
At IES, our experience in this area helps to ensure permanent, cost-effective, and safe solutions to indoor air vapour intrusion issues.