Proper sampling procedures are a vital first step in ensuring monitoring results are representative of a given discharge.  All sampling should be carried out by competent staff that is trained in relevant sampling and preservation procedures.  When both the competent authority and the licensee are sampling at the same time, aqueous samples should be split.  This will eliminate the introduction in sample variability when comparing data.

It is important that sample collection ensures the following criteria are met;

  • All sample collection sheets record whether samples are grab or composite and the time frame over which the composite was collected.  This is necessary as the interpretation of results, to demonstrate compliance, varies depending on whether the sample is a composite or grab (typically Condition 4 of licences provides details on interpretation).
  • Sample containers are clean and of an appropriate quality and type.  Different analysis requires different container types in order to ensure the integrity of the sample e.g.  metal analysis requires plastic containers to be used whereas, volatile organic solvents are required to be collected in glass vials filled to ensure no air space remains in the vial.
  • Sample location is carefully selected so that a reliable assessment of environmental compliance with ELVs can be made.
  • All sampling equipment is fully calibrated and maintained in accordance with manufacturer’s recommendations.
  • A representative sample of the discharge is collected.
  • Samples are kept cool during the period from collection to analysis.  Where necessary, when analysis cannot be conducted within the recommended timeframe, by internationally accepted standards, samples should be appropriately preserved.
  • Chain of custody documentation is maintained.  This is extremely important especially where analysis is sub contracted to an offsite laboratory, to ensure that all monitoring results are fully traceable.

 Groundwater Sampling

Many licences require ambient monitoring of groundwater in order to demonstrate no environmental impact from processes and discharges onsite.  Groundwater sampling requires specialised training and licensees should ensure it is only undertaken by appropriately qualified and trained personnel in accordance with recognised standards.

Guidance Documents

All Irish standards can be obtained from the National Standards Authority of Ireland (NSAI) details of which can be found at the following website:

EN ISO 5667-2:1994 Water Quality – Sampling Part 2 Guidance on Sampling Techniques:  This standard provides guidance on the techniques necessary to obtain samples for the purposes of quality control and characterisation.  

EN ISO 5667-3:1994 Water Quality – Sampling Part 3 Guidance on preservation and Handling of Water Samples:  This standard provides guidance on the precautions to be taken to preserve and transport waster samples.  This standard is especially appropriate when grab or composite samples cannot be analysed on-site and have to be transported to an offsite subcontracted laboratory for analysis. 

EN ISO 5667-10:1994 Water Quality – Sampling Part 10 Guidance on sampling of waste waters: This standard contains details on the sampling of industrial waste water. 

EN ISO 5667-11:1994 Water Quality – Sampling Part 11 Guidance on sampling of groundwaters: This standard contains details on the design of the groundwater sampling programmes, sampling techniques and handling of water samples. 

The UK Environment Agency has published a document called 'Technical Guidance Note (Monitoring) (M18) : Monitoring of discharges to water and sewer'. 

 Man sampling in river