"Mike Lyle" wrote in message
om...
My hosepipe -- presumably reinforced pvc -- has been around for a long
time, and I've just noticed that when I use it to fill a watering-can
the first couple of gallons are very frothy. At first I thought it was
traces of the washing-up liquid I sometimes use a drop of as a wetting
agent, but it's definitely the hose itself.

Question for the scientists: I assume I'm seeing products of the
breakdown of the material, so are they likely to be harmful to plants,
life, the planet, and everything?

Mike.

I have noticed this with new hoses as well.
I suspect that it is just the first rush of water mixing with the air in the
pipe to give you naturally carbonated spring water.
Seems to happen more in the hot weather, so it could even be air disolved in
mains water bubbling out as it goes through a hot hose.
Run a glass full of cold tap water and leave it to warm, and you often see
bubbles form on the inside of the glass - presumably gasses coming out of
solution as the water warms.

Cheers
Dave R