When we're talking about whether things are ending up in landfills, the federal role definitely has to be in conjunction with the provinces because landfills are pretty much entirely within provincial jurisdiction.
That being said, through the powers of CEPA to control toxics, it definitely can be used for sector-specific regulations or for controlling specific chemicals that are designated as toxic. That's where the risk management plans come into play around the specific substances.
It's one of those things where you have to look at the actual issue. Mercury, at least in the past, and probably still now to some extent, was an issue, and dental amalgams going into sewers. You need to have a take-back program or some way to recycle that product in order to have a mechanism for the dentists to deal with it properly, instead of having it end up in sewers.
It's a combined approach with whatever sectors: using the material, finding alternatives, applying green chemistry, and then having your regulation as the backup.