Lead poisoning of milk--the basic need for the foundation of human civilization

Three study sites along the roads with different automobile traffic densities were selected and cattle milk samples were collected every month from all the three sites. Lead concentration in samples were determined through atomic absorption spectrometer. Milk collected from area of heavy traffic contained 4.6-7.2 ppm of Pb, which is much higher than its permissible limit (0.3 ppm) according to FDA.