who knows, no-one quite possibly
Not us mere mortals that's for sure. But, my word, the speculation is fun!
Re the plasticizers; they are chemicals used to soften plastic. There are amounts of plasticizers in varying degrees in many plastics, such as gel tubes, drink bottles, etc. Simple infusion of products from such plastic containers is unlikely to lead to significant amounts of it entering the blood system. Transfusion of blood from a soft plastic bag, however, would do the trick. Plasticizers themselves are clearly not a banned substance, they are not 'performance enhancing'! And they are no smoking gun. They do not tell you what the 'soft plastic bag' contained (if indeed you can show they came from a blood bag). Certainly, in context, they are a pointer to blood doping but not proof. It's like finding syringes and blood bags in the team's trash; less than that imho.
More importantly, the test for plasticizers is apparently not approved/ratified. So my guess is that the 'Contador blood doped' will remain speculation and wont be acted upon. I reckon they'll take action over the clenbutoral though.
I am somewhat intrigued to know how the German TV station ARD were able to get these "exact values", how they even knew of the positive test, but that's a side issue and somewhat irrelevant.