I've always known plastic leaches chemicals regardless of what plastic it is. But since my alternative is nasty tasting, chlorine filled tap water that gives headaches - I chose to stick with Poland Spring until I can afford a distiller or something.
By the way which Poland Spring do you drink? Ever since my first Master-Cleanse fast 3yrs ago, I started to taste the plastic from the jugs in the water so I've stuck with the bottles.
If you want cleaner, purer bottled water.. Penta is the best. Now that's clean tasting water. http://www.pentawater.com
Expensive though.. $1.89 for a 32oz bottle.
If you drink that much water and are worried.. Spend a couple hundred on a distiller or purifer. The distillers are cheaper..can get a basic one for under $300.