I think that's an important issue.
The Canadian Environmental Protection Act is a framework, a piece of legislation. It enables the making of regulations to deal with environmental protection, health protection issues. It's been recognized by the Supreme Court of Canada on many occasions that environmental protection is an area that you can't have completely codified in law. Regulations are the place to do it. By fixing either a prohibition or a limit in the act itself, you tie the hands of what's intended to be a flexible regime and its ability to evolve with changes in scientific information.
I would say that a change to the act itself to crystallize these requirements weakens the regime. It doesn't make it stronger.