Research Progress of Organochlorine Pesticides in Breast Milk of Biological Samples in the Last Twenty Years

Hitherto, organochlorine pesticides (OCPs) have been reported with the highest residue level and the highest detection rate in human beings. Breast milk is the earliest biological medium used to research OCPs in humans and provides an effective way to study the exposure pathway of OCPs for humans, factors affecting OCPs concentration in breast milk, infant breastfeeding intake of OCPs, and OCPs excretion in humans. The conclusions of research in the last 20 years are as follows. First, the concentration of OCPs in breast milk continues to show a downward trend in world. p, p'-DDE, β-HCH and HCB are dominated OCPs in breast milk. In general, the residue levels of total OCPs in breast milk of developing countries show that in coastal areas and tropical regions they are higher than in developed countries, inland areas, and other regions, respectively. Second, concentration of OCPs in breast milk is affected primarily by age, delivery times and eating habits, and will not decrease during the breastfeeding period with waved drain mode. Finally, acceptable daily intake (ADI) of OCPs for infants is usually lower than the recommended value of WHO/FAO during the breastfeeding period. For infants of tropical regions where some OCPs are still used, the ADIs are obviously higher than the values recommended by WHO/FAO. In the future, the research of OCPs in breast milk will focus on these aspects. First, research on analytical or detecting methods of OCPs in breast milk will be carried out, the standardization of analytical methods will be promoted to expand the applied range of research data and improve the reliability and evaluation of the exposure risk for OCPs of humans, especially infants living in OCPs polluted areas. Second, research about the effect of OCPs on early development and future health of those infants, the excretion and accumulation rules of dominated OCPs in the human body such as metabolite DDE, β-HCH and HCB with multiple emission source, and statistical epidemiological studies using statistical method to reveal the relationship between OCPs in breast milk and disease of adult diseases will also be carried out.