Control measures
Validation
Validation is an investigative activity to identify the effectiveness of a control measure, e.g. if the control of cyanobacterial growth in a waterbody or the prevention of break-through of cyanotoxins into the drinking water is being achieved, as desired. Validation is not intended for day-to-day management, but is typically intensive when a system is initially constructed or a new measure is implemented. It should be repeated periodically, but particularly after changes in the system are undertaken.
Validation begins with considering the data and information which already exist, e.g. from the scientific literature, guidelines, regulations and their explanatory text, historical data, and – very important – your own operational experience.
Research on site, specific to the individual setting, is adequate for validation particularly where uncertainty is large as to whether or not a measure will “work” sufficiently well in this situation. Running intensified monitoring programmes during extreme blooms is particularly valuable for validation of the performance of control measures in situations of high load. If cyanotoxins are identified in the finished drinking-water after a cyanobacterial bloom, the whole system (and the Water Safety Plan as well) will need to be improved.
Specifically for cyanobacteria, it is important to note that some measures only show a time-delayed effect. For example, the reaction of nutrient-rich water bodies to reduced nutrient loads from the catchment is usually slow, and cyanobacterial biomass is often reduced only after certain threshold values in nutrient concentration have been undercut.
An outcome of validation may be a change in a control measure or its monitoring system, or confirmation that it is (still) adequate to ensure health protection from safety from potential cyanotoxin exposure.
Your validation activities should be documented together with the results of your validation. With such documentation, you can demonstrate having observed your duties of due diligence towards the public surveillance agency responsible for your setting, and also towards journalists and the general public in case questions or incidents arise.
Examples of the validation of measures from catchment to drinking water treatment are given here.