I was wondering if you could give pond owners some advice about minimising pollutants after their ponds have been created. Filling the pond with rain water is presumably a good start, but one of our ponds is located at the bottom of a slope and I’m pretty sure that pollutants in the soil do leach into the ponds during periods of heavy rainfall (if not all the time). Any idea what kind of substances are worst for wildlife and in what quantities they can be a problem? I’m thinking about things like weed killer, plant and lawn food, chemicals to control pests and even water from the sprinkler entering the pond.

Also, are there any good plant or animal indicators that can tell pond owners about water quality without the need for expensive monitoring instruments? For example does our absence of caddis fly larvae suggest any particular pollutants?

Cheers,

Helen.