Diethyl phthalate was found in two products. It was found in highest concentration (44 ppm) in a sunscreen (product #5), and we believe it was a component of the "fragrance" listed on the label. In a recent analysis of phthalates in Canadian adult and baby skin care products performed in 2007, DEP was detected in fragrances at levels of up to 25,000 ppm. In the same study, tested adult body lotions contained DEP levels of greater than 5,500 ppm. One tested diaper cream contained more than 2,500 ppm of DEP, and one baby lotion contained 571 ppm. Other phthalates found in our study include DEHP and DnBP. Of the 98 baby skin care products tested by Koniecki and colleagues, only one (a baby lotion) contained detectable amounts of DEHP (15 ppm). Two baby shampoos in the same study contained low levels of DnBP, with a maximum level of 1.8 ppm. The DnBP and DEHP found at low levels in our tested products likely were impurities and were not added intentionally.
In our study, the RDL varied by substance, depending on the hydrocarbon content; thus, the RDL influenced the phthalate detection threshold. For example, if the RDL of product #26 (a moisturizer) was the same as that of product #5 (a sunscreen)—for example, 1.0 ppm instead of 0.2 ppm—the concentration of DEP would have been reported as undetectable. Although this may have "protected" hydrocarbon-dense products from phthalate detection by GC/MS, the RDLs in general are in a similar range (Table 4).
Additionally, this pilot study was intended to make broad observations rather than specific implications, and this is simply a limitation of this laboratory technique for measuring phthalates. Polyvinyl chloride (PVC) plastics, which use phthalates as plasticizers, can leach various phthalates directly into the products they contain.[42,43] We were unable to locate any products cased in PVC, and all labeled containers of the products tested were considered phthalate free. It was cost prohibitive to test all infant products available at this retailer; thus, there may have been selection bias in product choice. However, an effort was made to obtain a diverse representation of products and manufacturers.
Another limitation is that only one container of each product was sent to the laboratory for analysis. Phthalate content may have varied among product batches; thus, we may have tested a particularly low- or high-phthalate product with respect to the true average phthalate content of the standard product. Manufacturing processes continue to evolve, and we could have tested an older and less contemporary product not representative of current product content. Additionally, all sunscreen products were not expired at the time of testing. Although analysis sought 17 specific phthalates (see Table 2), it is possible that novel phthalates not included among these 17 phthalates are being used in manufacturing and were therefore not detected in this study.
In 2002, a study performed an independent phthalate analysis of 72 adult personal care products and found that 72% (52 of 72) of products tested contained detectable levels of phthalates in concentrations ranging from trace to 3%. A follow-up study in 2008 noted a decreased or undetectable level of phthalates in 9 of 12 products retested. A 2007 analysis found detectable levels of phthalates in 44% (112 of 252) of products tested. We found detectable levels of phthalates in 13% (4 of 30) of our tested baby skin care products. Our study confirms that, overall, low or undetectable amounts of phthalates are present in baby skin care products although occasional products have higher levels. Also, there seems to be a trend of decreasing phthalate content in skin care products, given these data (our study, performed in 2009, is the most contemporary).
However, given the occasional baby skin care product with a higher phthalate level, it may be prudent to periodically monitor such products for phthalates. Perhaps manufacturing guidelines with regard to phthalates should be considered, along with eventual global standards for individual phthalates. There is certainly a need for continued research and investigation to help determine if there is a clear cause and effect between specific phthalates and human toxicity.
Financial disclosures of authors and reviewer(s): None reported.
Funded by a 2009 American Contact Dermatitis Society Clinical Research Award.
Dermatitis. 2011;22(05):272-276. © 2011 American Contact Dermatitis Society