We had an earlier discussion about that bit of research.
http://archive.reefcentral.com/forum...readid=1118475
IMO trading in glass bottles for plastic was an environmental blunder. On a recent walk along a stretch of beach far from any houses or road heads I saw so many plastic bottles washed up that it would taken a dump truck to put a dent in their number. Never saw that back in the days of glass bottles, then you just found beach glass which is nothing more than super heated sand when you get down to it. The plastic bag situation isn't much better when you consider how many sea turtles and sea birds try and eat them.