“plastic” is not specific enough to say for sure, but I would say probably not. First off, the acid in the rain is very low concentration unless you have an acid rain problem in your area. Second, most of the chemical structures I can find for plastics would not react with just acid, but there are some out there that probably would. Like I said, plastics covers a whole range of materials. What plastics being dumped in meadows in fields? If you mean some sort of landfill, then theres bound to be every kind of plastic in there, but generally plastic is unreactive and thats part of why its so widely used.