Synopsis on this article published in Environmental Health Perspectives –
- Polyfluoroalkyl compounds in Texas children from birth through 12 years of age
- By Schecter A, Malik-Bass N, Calafat AM, Kato K, Colacino JA, Gent TL, Hynan LS, Harris TR, Malla S, Birnbaum L.
Older children have higher levels of chemicals called PFCs – used in products to prevent staining and sticking – than younger children, although their levels are lower than a decade ago, finds research that suggests a blossoming trend reversal and a continued problem in older children.
A decade after industry voluntarily reduced production of certain types of chemicals known as PFCs, the widely-used and persistent chemicals can still be measured in children, although levels overall appear to be declining with time. The results are published in the journal Environmental Health Perspectives.
This research is important because a very limited number of studies of the U.S. general population have looked at PFC levels, especially in children. Because of possible health effects, it is critical to know how children’s exposure varies by age as PFCs persist and can accumulate in the body.
Many products contain PFCs – or perfluorinated compounds – to prevent sticking, repel stains and help mix and disperse liquids and foams.
The researchers report that age – not sex – was the biggest influence on PFC levels measured. They found that levels in the children’s blood increased with age. For example, the 12-year-olds had higher levels than those half their age who had higher levels than the infants. In contrast, levels between boys and girls were similar at any given age.
Overall, though, the results suggest that the four PFCs with the highest measured levels have declined over time in all the age groups. For instance, measured levels of two controversial PFCs – PFOS and PFOA – were lower in this study when compared to levels measured in children 10 years ago. In addition, while those under 3 years old still have PFCs in their bodies, the levels of some of the most pesky types are lower when compared to levels the older children would have had at the same age.
Industry voluntarily reduced production of some of these PFCs about a decade ago. This study cannot directly link the suggested blood level declines with the phase-out. Although PFOS were largely phased out in 2002 and PFOA levels are seem to be declining, the persistent chemicals can stay in people for at least 3-5 years.
PFCs have been used in food packages, non-stick coatings, fire-fighting foams, carpet coatings, and cosmetics and lotions. Children can be exposed via their mothers before birth and when breastfeeding. Other sources are water, dust and food, such as microwavable popcorn and fast food in coated paper wrappers.
Health concerns of PFCs are starting to be identified, but study results remain inconsistent. In children, some findings suggest changes in the age when puberty and breast development occur and some behavior problems, such as inattention and hyperactivity.
To research the PFC levels in children, the investigators tested 300 blood samples from children aged 0-12 years old in Texas. They measured the levels of eight PFCs in the samples and compared them by age and sex. The samples were from residual blood collected for other purposes in the Dallas Children’s Medical Center.
Four of the eight PFCs measured were detected in more than 92 percent of the children’s blood samples: PFOS, PFOA, PFHxS, PFNA. The median value of PFOS was 4.1 nanograms per milliliter (ng/mL), PFOA was 2.85 ng/mL, PFNA was 1.2 ng/mL and PFHxS was 1.2 ng/mL.
The levels of PFOS and PFOA were lower than national averages tested 10 years ago. However, the levels of these chemicals increased with age, especially PFOS. Its median was 6.3 ng/mL in 9- 12-year-olds, which is significantly higher than the 2.0 ng/mL in the 0- 2-year-olds.
Despite the declining trend of PFOS and PFOA in children after their phasing out, older children still have higher levels in their blood. This could be due to accumulation from past exposures. It is important to better understand children’s body burdens so as not to neglect possible health outcomes of these exposures in older children.