Harmful chemicals can be transmitted to the baby not only during pregnancy, but also via breastfeeding after birth. Contamination can occur due to exposure to e.g. pesticides or toxic chemicals in food and indoor air as many human biomonitoring programmes and projects have found out by testing breast milk on various substances.
As POPs are the most hazardous ingredients of polluted breast milk, breast milk has been tested by WHO for POPs within the process of the Stockholm Convention for several years. The last testing round spanned the period from 2010 to 2012.73 The results from the third, fourth and fifth rounds of the survey spanning the period from 2000 to 2012, are presented in a report based on the findings by Malisch et al.
Following the results the survey shows a mixed picture: POPs like PCDD and PCFD have fallen steadily from their earlier high level indicating the effectiveness of intervention measures. PCB decreased over time, but is still considered a human health concern. Chemicals newly listed in the Stockholm Convention in 2009 and 2011 like PFOS could be detected at values above LOQ for a majority of samples in more or less all participating countries. This shows that contamination and human exposure to PFOS in these regions is very concerning.75 Unfortunately many countries do not take part in the monitoring on a regular base of the WHO/UNEP human milk survey, even if they have the means like e. g. Germany.
Also other harmful chemicals can be found in breast milk. Knowing to have toxins in your breast milk is usually very scary for mothers. Therefore public communication about this topic should be done in a very sensitive way. However, breastfeeding should be maintained because it brings many health benefits for the children and the mothers. IPEN and the World Alliance for Breastfeeding Action (WABA) state together that “The contamination of breast milk is one symptom of the environmental contamination in our communities. Responsibility for this problem belongs to the industrial sources of contamination, not to breastfeeding women.”
https://www.wecf.org/wp-content/uploads/2018/12/WomenAndChemicals_PublicationIWD2016.pdf
https://www.wecf.org/wp-content/uploads/2018/12/WomenAndChemicals_PublicationIWD2016.pdf