Passive sampling relies on the molecular diffusion of substances (analytes) through a diffusive surface into an adsorbent.
This technique can provide a representative measurement of average concentration over a a period of time from days to months, even under conditions where levels of pollutants fluctuate and point measurements (e.g. sampling events) may not be representative.
Passive sampler systems generally have no moving parts, require no electricity and are simple to deploy and recover. The equipment to be deployed in the field is relatively low cost and low tech, making this a cost-effective technique.
After recovery, a laboratory analysis of the adsorbant material provides the average concentrations the passive sampler was exposed to during the deployment period.
Some examples include
- Bioavailability-based risk assessments
- Emission assessments
- Concentration mapping
- Pollution source identification
- The Patch (developed by NIVA)
- Benthic flux chamber (developed by NGI)
- Benthic lander (developed by NGI)
- POM cage (developed by NGI)