How much toxic exposure is experienced in China and in Vietnam?

And is there a way to reduce toxic exposure? Not obsessively of course, but to an extent that's reasonable and practical.

Also, is a probiotic supplement, multivitamin, and multimineral needed? I ask, because they're needed in the US due to soil degredation. You can survive without them of course, but they help ensure you're getting enough without exposing you to too much.