Why isn’t it a pollutant?
Legionella would not be a pollutant as it occurs naturally in water, however, it can be a hazard in building water systems if not effectively controlled. It would all depend on the frame of reference for the question.
What is the frame of reference?
The frame of reference would need to consider where the water comes from, what has happened to it, where it is going and most importantly who is asking the question, and why and what they would reasonably expect.
Once the frame of reference is known, they will need to ask if Legionella is a contaminant. This will also depend on the other factors of the frame of reference but the answer is likely to be ‘no’ if Legionella is detected at expected levels. So in river water, it is unlikely that Legionella in very low numbers will be considered a contaminant but in highly purified water for use in a nebuliser, it would likely be considered a contaminant.
If it is a contaminant then it is a special subset of contaminants – a pollutant. A pollutant is something that is likely to have some form of undesirable effect or do some form of harm. Some frames of reference will only look at artificial pollutants, but pollutants can equally be naturally occurring. But again the frame of reference is important when doing this ‘pollutant’ risk assessment – undesired effects or harm to whom or to what (the wider environment, localised plants and animals, a person)?
So if the frame of reference is water from a mains water provider going into a building with Legionella bacteria multiplying in the system to moderate levels and being discharged to a foul sewer, and, if the individual carrying out the risk assessment is the Environment Agency, the answer is most likely no. They expect Legionella to be present in the water and as it is on its way to the treatment plant it is unlikely to have undesirable effects or do harm in this frame of reference.
If the frame of reference is moderate levels of Legionella in water used in a hospital nebuliser by patients with breathing difficulties and the risk assessor is Public Health England, then I believe the answer is likely to be yes. The Legionella bacteria are not expected to be there at these levels, so it is a contaminant. The clear causal link between the contaminant and potential harm to the patients would by definition make it a pollutant within the frame of reference of the patient.
This guide is of a general nature; specific advice can be obtained from Assurity Consulting.
Assurity Consulting is the UK's leading independent compliance consultancy specialising in workplace health, safety and environmental solutions. We have over 35 years' experience of helping customers of all sizes, from across all sectors, manage their compliance responsibilities, making sure that their organisation is compliant, their employees are safe, their processes are cost effective and their management team is in control.
