These chemical compounds are highly stable and linger in the environment. Thanks to their water-, oil- and stain-repellent properties, they are widely found in everyday items, such as non-stick pans, waterproof clothing, food containers and fire-fighting foams. Their widespread use has harmful effects; they can enter the human body during pregnancy via the placenta and continue to build up through breastfeeding, food, drinking water, polluted air, or contact with products containing them.
Due to their impact on health, these chemical compounds have become a focus for concern and research. “They have been linked to endocrine disruption, increased cholesterol, and effects on the liver and development. They can build up both in the body and in the environment. So, exposure to PFAS can be regarded as chronic. What is more, they take years to degrade. This reinforces the need for biomonitoring studies such as ours," explained Anne San Román, co-author of the study.
This joint study by the University of the Basque Country (EHU) focuses on children, as they are a particularly vulnerable group. Exposure at an early age can cause harmful effects at lower doses than in adults and increase the risk of future diseases.
The analysis, carried out on the plasma of 315 minors, detected 18 different compounds among the 42 studied, with detection rates ranging from 70% to 97% for the most common ones. “The data obtained show that we are highly exposed. It is difficult to know whether the levels of PFAS found in children's bodies are high or low because this issue has not been studied sufficiently in order to specify safe limits for humans, but their presence is already a cause for concern and it is important that this type of research be expanded to better understand their effects and find ways of minimising them," explained Professor Nestor Etxebarria.
Regarding the effects of PFAS on health, the study assessed the potential risks to the liver and development and concluded that, in general, there is no evidence of immediate danger. “We have no evidence of worrying concentrations of PFAS in the population studied. However, this does not mean that the risk will decrease in 10 years' time. What does not appear worrying now could be worrying in the future, because it is still unknown whether they could be responsible for future diseases," pointed out Etxebarria and San Román. They added that current methods for assessing risk have significant limitations, as they are based primarily on studies conducted on animals, which reduces their accuracy when extrapolated to humans. So they warned of the need to adjust risk assessment methods and conduct more people-centred studies to obtain more realistic data.
Differences in terms of age
The study is part of the INMA (Childhood and The Environment) project, launched in 2006 with the aim of analysing the impact of environmental pollutants on child development. The EHU research analysed children's exposure to PFAS over time by examining blood samples collected by the INMA project between 2011 and 2022 in the Gipuzkoa cohort. Specifically, in the Goierri and Urola districts, areas characterised by a strong presence of the iron and steel industry. “We analysed the plasma of the children at three key stages of development: at the ages of 4, 8 and 14. This enabled us to assess the evolution and trends in PFAS levels as children grow up, and to confirm that PFAS concentrations decrease with age.” As Etxebarria and San Román went on to explain, “in early childhood, too, levels are mainly related to maternal exposure (through the placenta and breastfeeding), while in adolescence, environmental factors become more important”.
Furthermore, research shows that the presence of PFAS varies according to age. They observed that compounds regarded as classic, such as PFOA or PFOS, which began to be regulated in 2006, predominate in younger children. By contrast, adolescents have higher levels of emerging PFAS, probably because these compounds began to be used more widely when they were older, and replaced compounds that had already been regulated. San Román and Etxebarria highlighted the fact that “the data most likely reflect the exposure typical of each period. That is why it is so important to repeat these studies periodically to capture the changes that are taking place and to be able to study the consequences they have on our bodies”.
Insufficient and outdated regulation
Based on the data obtained, the research team concluded that current regulations have not been entirely effective, since, despite the restrictions imposed on some PFAS, the restricted compounds are still present in children. Furthermore, they believe that the regulations need to be updated to include emerging compounds, the presence of which has been demonstrated. In this regard, they highlighted the need for further studies on the toxicity of the most recent PFAS, the danger of which has not yet been clearly established.
Further information
Nestor Etxebarria is professor of chemistry in the Department of Analytical Chemistry and deputy director of the Research Centre for Experimental Marine Biology & Biotechnology in Plentzia (PiE-EHU). He leads the IBea research group, which focuses on the development of non-targeted analytical methodologies and their application to environmental and ecotoxicological problems. He lectures on the Degree Course in Chemistry and coordinates the Master's in Environmental Contamination and Toxicology.
Anne San Román, a chemistry graduate who completed the above-mentioned Master's, is currently a pre-doctoral researcher. This article is part of the thesis she is writing up in the field of Environmental Pollution and Toxicology. Etxebarria is supervising San Román's PhD work, which is being carried out as part of a collaboration between the Biogipuzkoa Health Research Institute, the Gipuzkoa Department of Public Health, the Research Centre for Experimental Marine Biology & Biotechnology in Plentzia (PiE-EHU) and the Ibea research group.
END