OECD 170-4: 2012 - Simulated-use bactericidal activity for disinfectants for swimming pools and SPAs (Internal procedure, based on OECD 170-4).
Currently, there is no guide or standard describing the simulated use test procedure but based on the characteristics indicated by the Spanish authorities, IVAMI has developed a test procedure to evaluate the bactericidal activity of disinfectants for swimming pools and spas. We advise you to consult the authorities of the country where you are going to register your product, the characteristics that this test must have to verify that it complies with the following.
In the simulated use test, 15-litre tanks are used which are inoculated with the following bacterial strains indicated by the EN 1276 standard: Escherichia coli, Enterococcus hirae, Pseudomonas aeruginosa and Staphylococcus aureus. In addition, in the case of spa disinfectants, Legionella pneumophila must be added to the test. The test can also be requested with the bacteria indicated by OECD 170-4 guidance: Escherichia coli, Enterococcus faecium, Pseudomonas aeruginosa, Staphylococcus aureus and Legionella pneumophila. Three replicas are carried out with the test product, applying the dose indicated by the client and a control, without test product. The test is carried out with an artificial organic load compatible with a pool that resembles the bather load, using BFA (Body Fluid Analog). The client must indicate, depending on whether it is applied in pools with circulation, whether a water recirculation and pumping system must be included in the test. The test temperature depends on the temperature to be declared. The OECD 170-4 guidance indicates a temperature of 25ºC to 30ºC for swimming pools and 34ºC to 36ºC for spas. The duration of the test should be in line with the frequency of application of the product. The minimum duration is 24 hours, although it is recommended that it be at least two days. To resemble real conditions of use, it is recommended to re-inoculate the tanks, for example, after one or two days of treatment to check that the product is still active. The pH and bacteria concentration should be monitored periodically to indicate the logarithmic reduction on a regular basis. Following the indications of OECD Guide 170-4, the product will be considered to have bactericidal activity if a reduction ≥ 4 log10 is demonstrated. Monitoring times must be requested by the client, according to the mode of use of their product, for example, after 30 seconds, 2 minutes, 1 hour and 24 hours (note that measurement times must be requested within the opening hours of the laboratory). Additionally, if requested by the client, we can also monitor the concentration of the active ingredient of the test product. If you wish to have the active substance of your product monitored, you must consult us so that we can confirm whether we can determine the concentration of the active substance at the requested concentration.