Permethrin and Mosquitos?

[Wandering Daisy]

Does anyone know if washing permethrin treated clothing in streams or lakes is acceptable with respect to aquatic life in those waters? I worry about rinsing out my bugs-off shirt. I usually do it in a good flowing stream so at least anything that gets into the water is quickly diluted.

[bobby49]

I don't think that it is safe for aquatic life.

If I had permethrin treated clothing, it would be outer layers. As a general rule, the only item that I rinse in a stream is a synthetic t-shirt, and that is not an outer layer.

[c9h13no3]

Does anyone know if washing permethrin treated clothing in streams or lakes is acceptable with respect to aquatic life in those waters? I worry about rinsing out my bugs-off shirt. I usually do it in a good flowing stream so at least anything that gets into the water is quickly diluted.

Permethrin is a pretty water hating compound. It has a log P of about 6, which means it prefers a greasy solvent a million times more than water.

Course, it also comes with the GHS09 warning which has a picture of a dead fish. So even though not much will end up in the water, it's really bad for fish & swimming critters. A few micrograms per liter will kill trout.

So the answer is, I'm not sure. I'd guess a quick rinse in a cold & flowing stream is probably fine. Rinsing in a bowl, and then scattering the rinse water onto rocks would be even better. Permethrin has a short half life when exposed to sunlight. But we're learning that many pesticides persist longer in the ecosystem in ways we didn't expect (ask the bees).