Spread over a childhood of say, 8 years, 1/4lb is only 28mg per day. That's a couple grains of rice. So, yeah, it's not much dirt.
I'm clearly not that concerned, as I don't keep my child in a bubble, but environmental lead is detrimental to society at large and something that we should make every reasonable effort to reduce.
8 years is a bit long, right? Newborns aren't playing in the dirt. By at least age 6 I would hope that most kids have basic hygiene to not be eating dirt. At such a low dose over such a long time, it's unlikely to accumulate. Plus, 28mg of dirt is still like eating a teaspoon of it.
"make every reasonable effort to reduce."
I agree. It's the reasonable part that comes up for debate. To me, it seems reasonable to live in an area that has elevated lead in the soil while not growing crops or raising chickens. It's more reasonable to replace the "lead free" plumbing components with truly lead free components, carefully select toys (eg no Chinese), and stay away from certain foods (carrots are a big one if I remember correctly).
I'm clearly not that concerned, as I don't keep my child in a bubble, but environmental lead is detrimental to society at large and something that we should make every reasonable effort to reduce.