Although usually when we think about laboratory testing and Legionella the first thing that springs to mind is microbiological analysis (e.g. Colony Counts & Legionella), chemical analysis can also play a very important part. Two examples of where this applies are:

L8, The Approved Code of Practice & Guidance states that “The risk from exposure to Legionella should be prevented or controlled and that the precautions taken should be monitored to ensure that they remain effective”. In cooling systems one way of achieving this is to monitor chemical characteristics of the make-up and cooling waters in order to try and identify changes in water chemistry. Recommended monitoring checks for good operating practice are supplied within L8 and include testing for pH, hardness, alkalinity, chloride, sulphate, conductivity & suspended solids amongst others.

L8, The Approved Code of Practice & Guidance states that “The risk from exposure to Legionella should be prevented or controlled; precautions should include the use of water treatment techniques”. A common method of treating hot and cold water systems is via the use of ionisation techniques, (e.g. the electrolytic generation of copper and silver ions.) This method, if controlled properly, is effective against planktonic legionella in hot water systems, but critical to its use is the management of the levels of silver and copper ions. Considerations on the levels to be maintained should include the effective concentrations. This can be dependent upon the chemical nature of the water and therefore checks for hardness, pH & dissolved solids should be undertaken. L8 supplies guidance on such issues such as levels to be maintained and how often (and where from) samples should be taken for laboratory analysis.

The above examples show where chemical testing by your chosen laboratory can be used alongside microbiological analysis in order to confirm that systems are being controlled properly.

A key consideration when choosing a laboratory to supply the services mentioned is obviously the quality of any analytical data supplied. Relevant information that should be considered when assessing your laboratories capabilities should include the following:

Quality Issues

• UKAS ISO 17025 accreditation.
• Autonomous in-house quality department, systems and protocols.
• Participation in external proficiency schemes.
• Best practice methodologies being operated.
• Representatives on national and international method development relevant committees.

Other important issues include liaison with the laboratory (this forms a key part of ISO 17025 accreditation for laboratories) in order that a problem free service is supplied. It is important that the laboratory understands what is required & the following items should be considered, when arranging laboratory analysis:

• Analysis needed to meet specific requirements.
• Supply of fit for purpose sample bottles (Laboratory should supply these prior to sampling).
• Customised labels and submission sheets (Laboratory should supply with bottles).
• Appropriate sample collection organised.
• Agreed reporting formats.
• Ensuring that a fit for purpose sample is taken and delivered to the receiving laboratory promptly under the correct conditions.
  

Article by:
Jonathan May
Business Development Manager
ALcontrol Laboratories
T: +44 (0)1709 841007
E: jonathan.may@alcontrol.co.uk