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Monitoring Solutions

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.

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