We claim in the Anti-Textbook that externalities are not only pervasive but that they're important, are not adequately addressed by policy and are not given nearly adequate acknowledgement in the economics textbooks. If you were paranoid, you might suspect that this had something to do with a desire to make the outcomes of the economic system look a lot better than they actually are...
As brief update, I offer this recent article from The Guardian: "Study maps chemical residues in children's diets". While that reports on food in France, I doubt the results would be much different for anyone reading this, no matter where you live.
this report from the Canadian Broadcasting Corporation about antidepressants in the water. For me, the surprise is not that drugs from pills we ingest end up being excreted and wind up in the water supply. It was that a quarter of the population in Montreal is reportedly taking anti-depressants (like amitriptyline, whose chemical structure pictured on the right).