I think that all of these items were appreciably worse under the Communist regimes of the 20th century than any Western regulated Capitalist county. I mean, at least child labor, wars for exploitation of resources, slave labor, human trafficking, global warming, ecological disasters, and especially famine and malnutrition. Maybe you're right about lead poisoning though... The Western democratic capitalist societies probably had worse lead poisoning than, say, the USSR, where millions of people turned to cannibalism to feed their families.
Although even regardless I'll re-iterate my point about Capitalism from earlier that you cannot have free markets without free peoples. If people are held in slave labor or child labor, or what have you, that is by definition not a free market.