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The NLS offers a routine Passive Sampling service to support the monitoring and analysis of most aqueous environments. As leaders in this field, the NLS can deliver more accurate results at a lower cost than traditional, intensive “spot sampling”.

Why Passive Sampling?

Traditionally ‘grab sampling’ methods are used to monitor for Hydrophobic chemicals and other pollutants in water. However, the reliability of this method is questionable as there is a chance that pollutants can be missed because a sample was taken at the wrong time; the ‘spot check’ approach is only able to capture any pollutants present in the column of water, the moment the sample is taken.

What are the benefits of Passive Sampling?

  • Can be deployed in almost all aqueous environmental conditions, regardless of water quality e.g. surface waters and effluents
  • Estimated to cut the cost of routine water sampling by up to 30%. Traditional intensive sampling to obtain a more accurate result can be very labour intensive as the same spot needs to be revisited time and time again
  • Selectively samples residues from the dissolved (readily bioavailable) phase
  • Allows for the concentration of trace, yet toxicologically relevant, contaminant mixtures over extended periods of time
  • Concentrates trace levels of chemicals resulting in much lower detection limits and is therefore able to meet the higher monitoring demands of the new Water Framework Directive
  • Provides time-weighted average concentrations and gives realistic chemical loading levels on rivers from various sources
  • Can detect episodic changes in environmental contaminant concentrations, which are often missed with conventional grab samples

What Passive Sampling devices are on offer?

The NLS has perfected equipment that integrates two key methods of passive sampling – the Semi-Permeable Membrane Device (SPMD) and the Polar Organic Compound Integrated Sampler (POCIS). This means a single sampler can be used to test for two major groups of contaminants at the same time – those that readily dissolve in water, such as herbicides, and those that are only slightly soluble, such as polychlorinated biphenyls (PCBs).

What tests are supported by NLS Passive Sampling?

Click here for a list of compounds that can be identified by the NLS using SPMDs

Click here for a list of compounds that can be identified by the NLS using POCIS

How do I find out more (including information on successful deployments)?

Download our Passive Sampling leaflet.

To discuss the application of Passive Sampling for your organisation, please contact our Customer Service team.