Clofibric acid is a cholesterol-lowering drug.
Concentrations were from 1 to 100 nanograms per liter. The also found a toxic pesticide ingredient, lindane, in about the same concentration. Many of these aquifiers serve as sources for drinking water. Subsequently, other researchers have found drugs from chemotherapy, antibiotics, hormones, antiseptics, and beta-blocker heart drugs. They have also detected residues of drugs to control epilepsy and ones that serve as contrast agents for diagnostic X rays, etc.