More extensive studies absolutely need to be done.  However, there's already well-documented evidence of the number of chemicals in our food supply just in comparing commercially grown versus organic -- and how many people actually pay extra for organic consistently or grow their own organically? 

Here's one attempt to get a large public sample re mercury:  _Test_  They're trying to get a minimum of 10,000 samples.  We get mercury from our water supply in many areas and from contaminated seafood (tuna and other large fish).

Here's another way to compare foods based on growing techniques:  _FoodNews_ 

And that's just in our produce.  That's not counting the contaminants that we know are in the ground, oceans, and fresh water supplies from toxic dumping over the years, as well as continued air pollution, etc.  These poisons aren't going away and our government seems to be intent on weakening what protections we have.  Cigarettes are a problem, yes -- but the rest of us don't have any choice about what's in our environment, especially stuff we don't even know about.

Here's an organization that's dedicated to keeping up with what's going on and keeping the rest of us informed:  _EWG_.  More studies are underway for sure -- starting with small random samples, but soon to progress to larger population samples.  When you're talking involuntary environmental exposures, you're talking huge numbers of people.  One of the problems is funding right now because all this testing takes money and the government has been making cutbacks in this area.