Biomonitoring is a long-term project because what we're really interested in is the direction in which things are going. To me, absolute numbers at this point don't mean very much because we really don't have any reference values.
The reason that blood is monitored is that's the easiest thing to do. Tissue sampling is of course much harder, and people would not line up to have fats taken out of them--some might, yes...large amounts of fat. There's the underlying hypothesis that when you're measuring blood levels it's also indicative of the fat-soluble compounds of what is stored in the fat. Also, you have to remember the same argument, at least, that I've used: just because something is present in the blood doesn't mean that it's doing harm; just because something is present in the fat doesn't mean it's doing harm either.
This business of bioaccumulation I think very often is quite misinterpreted, and it's very difficult to do justice to these issues in a few minutes. What everyone really should be doing is reading a book called The Dose Makes the Poison, by Alice Ottoboni. I would really suggest that, because it will give you a lot more insight than what we can give you here. It's just a superb book on toxicology. It gives you the timeframes that are really relevant and what bioaccumulation means, and whether or not you should worry about the build-up in fat, which is not necessarily the case. Just because it's there doesn't mean that it's doing any harm.
You have to start somewhere. We started the process of biomonitoring. The CDC in the U.S. does this extremely well, and we will see the direction in which things are going. The important thing is to see whether or not you can relate those blood levels to any observable phenomenon in humans, and so far, as far as I can tell, that just hasn't happened. That is really what we're looking at, but in order to see that you have to have the data. So we are in the data-accumulating stage.
The question that you posed about whether or not we're too late is a very good one. Well, you have to start somewhere. We may be too late now, but we may not be too late for the next generation. We have to gather the data and see what we can make of it.