US review: blood concentration of drugs 1000x times higher than pollutants

Rappaport et al (2014)  investigated the occurrence of chemicals in blood of healthy human populations from the US. They classified the chemicals in 4 groups:

1. endogenous chemicals (from intrinsic human metabolism), 
2. food chemicals,
3. pollutants or,
4. drugs.

In total blood concentrations of 1,561 chemicals were obtained. They reported, among other obeservations, that blood concentrations of pollutants were 1,000 times lower than those of medicinal drugs. Figure 2 of their paper is added below.

The paper shows convincingly that concentrations of exogeneous medicinal drugs are - in average -3 orders of magnitude higher than pollutants! That really pose the question: how is the balance between adverse health effect caused by drugs and health effects of pollutants? Are pollutants indeed the priority chemicals when studying environmental health issues?