Human milk from seven US cities was analyzed for total DDT (DDT plus DDE) content. The mean of 138 samples was 0.17 ppm (range, <0.02 to 0.83 ppm) which is in excess of the World Health Organization's recommended maximum concentration in cow's milk (0.05 ppm.)
Use of commercial exterminators was associated with lower DDT levels than was personal home use of pesticides; donors using butter had lower concentrations than those using margarine. DDT levels diminished with increasing maternal age and milk obtained after nursing contained significantly more DDT than milk obtained at the start of nursing.
While no adverse effects to infants due to DDT in human milk has been documented, systematic monitoring of DDT and other environmental pollutants in man is needed.
Wilson DJ, Locker DJ, Ritzen CA, Watson JT, Schaffner W. DDT Concentrations in Human Milk. Am J Dis Child. 1973;125(6):814-817. doi:10.1001/archpedi.1973.04160060026005