The evidence that using household bleach impacts directly on waterways and aquatic life is far from equivocal. According to the industry (not always the most unbiased source) , chlorine bleach traces are present at such low concentrations in waste waters, having been rapidly reduced to chloride ions, that there is no real possibility of the formation of trace toxic by-products.
But the real ethical issue centres around manufacture. Bleach is from the organochlorine family of chemicals, compounds rarely found in nature and which can take centuries to break down.
Greenpeace has called for a complete end to organochlorine production. Arguably, by buying household bleach, although it can be considered relatively innocuous in itself, it helps to prop up the whole organochlorine industry.
Hydrogen peroxide is a bleach Jess which is H202 and is therefore completely and safely biodegraded. It is therefore completely safe to use in your loo. I've just realised you're being funny jess sorry for the pompous lecture 