The research is some of the first to show that a new class of pollutants can be found in human breast milk, alongside the very fat, soluble, persistent organic pollutants (POPs) (toxic organic compounds that remain intact for long periods of time in the environment and accumulate in the fatty tissue of living organisms).
Unlike levels for POPs which were generally similar in all milk samples reflecting underlying environmental exposure, the levels of UV filters varied significantly between samples, the study claims.
Researchers, led by Margret Schlumpf at the University of Zurich in Switzerland, tested the presence of 8 UV filters in samples of human breast milk (Bp-2, Bp-3, EHMC, HMS, 4-MBC, 3-BC, OC and OD-PARA) chosen for their potential endocrine disrupting effects, along with parabens, musk fragrance chemicals and a number of POPs such as polychlorinated biphenyls (PCBs).
Samples of breast milk were taken from nursing mothers during the months following birth and participants were asked to complete a questionnaire detailing their nutritional habits, profession, domicile and use of cosmetics during pregnancy and lactation.
Fifty-three mothers successfully completed the cosmetics section of the questionnaire providing details of each product they used and how regularly. The UV filters present in the products were then investigated by the researchers.
Presence in milk correlates to product use
According to Schlumpf, presence of UV filters in the breast milk correlated with reported cosmetics and sunscreen use.
“The total use of all UV filters was significantly correlated with their presence in breast milk as were the filters OC and 4-MBC,” she told CosmeticsDesign-Europe.com.
However, the the correlation between EHMC use and presence in milk samples was not significant, and the sample sizes for the other UV filters were not large enough to perform correlation statistics.
Correlation studies between cosmetics use and parabens could not be done as much of the exposure comes from food products and detailed information about each food product consumed would be impossible to obtain, Schlumpf explained.
In addition, as fragrance details are not required on the label, correlations between presence of musk chemicals in the milk and cosmetics use could not be performed. However, a number of parabens, and musk chemicals were found in the milk sample, according to the study.
Effect of UV filters on the infant
Although the study suggests that some UV filters can find their way into human breast milk via maternal exposure, which Schlumpf says was not previously thought to be the case, their effects on the infant remain unknown.
“First of all, we need to know what the single substances do. Many are not tested [for their endocrine disrupting effects] as yet and this is ongoing work. When you know what the single substances do, then we can look at mix of substances,” she said.
“There are some studies on 4-MBC and 3-BC that suggest they are clearly reprotoxic, [they can] disturb female sexual behaviour, and change the weight of the prostate in males. [These are] mostly rat studies,” she added.
New pollutants in milk
According to Schlumpf, this study illustrates that not only do the POPs show up in the milk, there are many new ones. These are not as fat soluble, but they still accumulate, she said, although maybe not over such a long time. “They have a capability to stay in the body longer than we expected them to,” she said.
For Schlumpf, obtaining information about the simultaneous exposure of humans to endocrine disrupters is especially important as they can act together.
“Human milk was chosen because it provides direct information on exposure of the suckling infant and indirect information on exposure of the mother during pregnancy,” she said.
Source: Article in press
Exposure patterns of UV filters, fragrance, parabens, phthalates, organochlor pesticides, PBDEs and PCBs in human milk: Correlation of UV filters with use of cosmetics
Margret Schlumpf et al
2010 doi: 10.1016/j.chemosphere.2010.09.079