With a p-valve/catheter setup in a drysuit, sure.
In terms of environmental damage, it's pretty minimal. Fish are peeing all the time, and there aren't that many divers. That said, there are some at least theoretical issues. Mostly, you're adding a source of nitrogen (urea) to the water. That can feed algal blooms. Where I live, it won't make much difference at most sites because there's plenty of nitrogen in the water. In Florida (or other tropical locales), I suppose it might if enough people were peeing in the water. But it would be a really local effect, as in right on the dive site and nowhere else. Urine (unlike feces) is generally pretty sterile, especially from men. (Women are more prone to UTI, so there's a greater risk of lack of sterility there, and I don't want to think about how things work with a she-p in terms of bacterial exposure.)
On the other hand, with wetsuits there's an old line about 2 kinds of wetsuit divers. There are those that will say they pee in their wetsuit, and those that will lie about it.