Negative on the treated lumber...
Before 2003 treated lumber contained Chromated Copper Arsonate, a highly toxic and regulated Chemical.
Since then Treated lumber contains a more expensive but less harmful TO HUMANS Amine Copper Quat and Copper Azole.
These still kill algae, and the small plankton and zooplankton, plus small baitfishes etc. It is also highly corrosive to Steel and Aluminum (screws, bolts, brackets, etc.)
You want Vigin wood, so it will decay and provide food and a home for the basic food chain...plus cover for larger fish.