There are unlikely to be people in the US with blood levels less than 1 order of magnitude less than the EPA action threshold. Lead is in your drinking water, food, and if you lived near anything with leaded - your air.
We used to use lead based pesticides at the dawn of the 20th century, if you eat any food grown in the midwest you are exposing yourself to reasonably large quantities of lead.
We used to use lead based pesticides at the dawn of the 20th century, if you eat any food grown in the midwest you are exposing yourself to reasonably large quantities of lead.