Dutch water boards urge care with pet flea treatments

The Union of Water Boards is advising owners to use flea and tick treatments only when needed, keep recently treated dogs out of open water and put hair from treated animals in residual waste. Leftover products and used flea collars should go to collections for small quantities of hazardous waste. Board member Sander Mager said protecting pets from parasites remains important. [1] [2]

The appeal follows concerns about chemicals reaching waterways. The Rijnland water authority has detected elevated levels of imidacloprid near a wastewater treatment plant in Noordwijk, with lower levels further away. It considers pet flea treatments a very likely source. Some substances used in flea treatments also have other uses, however, so their presence in water cannot all be attributed to pets. [3] [4]

The risk varies by chemical. STOWA calculated that, for seven of 16 substances it examined, less than 10% of estimated use entering sewers could be enough to breach a local surface-water standard. For four substances the calculated threshold was above 60%; data were insufficient for the other five. [3]