07
Aug
Over 60 Biomarkers of Pollutants and Pesticides Found in Hair Analyses of French Children
(Beyond Pesticides, August 7, 2024) Using mass spectrometry techniques, researchers in Luxemburg and France detect 69 biomarkers of pollutants and pesticides—12 of which are banned—in hair samples from over 200 French children. This study, published in Environment International, is the first to target over 150 biomarkers in a single hair sample, which “represents the most comprehensive assessment of chemical exposome in humans,†the authors say.
All children in the study were 3.5 years old and recruited from the Étude Longitudinale Française depuis l’Enfance (ELFE) [French Longitudinal Study since Childhood] cohort in the country of France, a major pesticide consumer in Europe. The ELFE survey is a joint project between the French Institute for Demographic Studies (INED) and the National Institute of Health and Medical Research (INSERM), which provides the first comprehensive national scientific investigation of children in France by following them from birth to adulthood.
Through analysis of hair samples from children in the ELFE cohort, this study evaluates pesticide exposure and compares it with prenatal exposure data from their mothers while also, according to the scientists, “investigat[ing] the roles of children’s biological sex and geographical differences as possible determinants of exposure.â€
Exposure to pesticides during early childhood poses significant health risks. In assessing 32 chemical families through liquid chromatography tandem mass spectrometry and gas chromatography tandem mass spectrometry in 222 hair samples, exposure markers can be identified in children from the ELFE cohort. Biomarkers, according to the U.S. Environmental Protection Agency (EPA), are “measurable substances or characteristics in the human body that can be used to monitor the presence of a chemical in the body, biological responses or adverse health effects.â€
Hair analyses were chosen as a sampling method as they are non-invasive and provide simplicity of collection, storage, and analysis. “During growth, hair traps chemicals from the bloodstream, forming a historical exposure record,†the authors state. “Moreover, hair samples can be analysed years later as hair can retain pesticides and other chemicals well due to its durable keratin structure, which preserves chemicals from degradation by environmental factors like light, microbial activity and temperature.â€
In the study, the scientists find that, “Among the biomarkers tested in children’s hair samples, 69 had a detection frequency of ≥ 50%, with 20 showing a 100% detection rate. Sex-specific differences were observed for 26 biomarkers, indicating the role of the child’s sex in exposure levels. Additionally, regional differences were noted, with Hexachlorobenzene varying significantly across the different French regions.†Over 100 different types of pesticides from the various chemical classes were detected in at least one sample, twenty of which are organochlorines. Organochlorines are a major chemical class known as which impact hormones that play an essential role in growth and development. Exposure to these compounds at a young age is especially harmful. The majority of the detected pesticide biomarkers are known or suspected endocrine disruptors. The most notable of which include fipronil and piperonyl butoxide (both found in 100% of samples), permethrin and α-endosulfan (99%), tebuconazole (96%), and carbaryl (85%).   Â
In each hair sample from the children, the number of chemicals detected ranged from 55 to 82 compounds out of the 159 biomarkers that were screened for. The authors note that, “12 banned compounds were detected in > 10% of the children’s hair, and these were from the organochlorine, polychlorinated biphenyl (PCBs), and brominated flame retardant (PBDEs) families.†The presence of these chemicals highlights the persistence within the environment of many pesticides that can affect multiple generations even after being banned.
This study reveals 26 biomarkers, including synthetic pyrethroid insecticides that impact nerves and brain function, with significant differences between the sexes, which suggests that “the child’s sex played a significant role in the model for these specific biomarkers. Specifically, 15 biomarkers showed significantly higher levels in males, while 11 biomarkers exhibited significantly higher levels in females. In particular, among these biomarkers, pyrethroid parent compounds, permethrin and tetramethrin, were found at significantly higher concentrations in females. In contrast, the levels of their metabolites, Cl2CA, 3-PBA, and CDCA, were significantly higher in males,†the scientists state. Permethrin is known for not only neurotoxicity but also endocrine disruption and reproductive effects, particularly for females. The authors continue by saying, “It is possible that these variations stem from inherent biological differences, encompassing hormonal and metabolic variations, along with societal factors that shape unique interactions between boys and girls with their environment.â€
Regional differences in the results are also noted. Eleven biomarkers show differences in exposure, including three organochlorines: hexachlorobenzene, metazachlor, and metolachlor. The authors postulate that, “These variations could be due to localized agricultural practices and specificities in the local food supply chain in each region. Furthermore, the overlap of certain clusters is likely attributable to the broad range of biomarker concentrations that uniformly influenced all regions. Compounds such as pyrethroid parents, which showed uniform concentration levels across all regions, in both urban and rural areas, exemplify this phenomenon.”
Within the ELFE cohort sampled, 46 of the mother-child pairs took part in previous sampling, with additional insecticides detected. “Correlations were performed to investigate potential links between the exposure of mothers (indicative of prenatal exposure) and their corresponding children (indicative of post-natal exposure). The results of the investigation revealed that, except for Fipronil, Fipronil Sulfone, and Azoxystrobin, there were no statistically significant correlations between the levels of biomarkers found in the hair samples of the mothers and that of their respective children,†the researchers find. “These findings suggest the possible shared sources of contamination with the children. The detection of chemicals such as heptachlor (59%), metazachlor (61%), and malathion (78%) in more than half of children’s hair samples, but rarely in the pregnant women’s samples (heptachlor 2%, metazachlor 2%, and malathion 0%), can suggest age-related exposure differences. Such variations might arise from children’s frequent outdoor activities and direct contact with grass, soil, or plants treated with specific chemicals.â€
The elevated levels of pollutants, classified as both persistent and non-persistent, in young children highlights exposure risks during key developmental stages that are not fully evaluated by EPA when performing risk assessments for pesticides. With multiple routes of exposure, including oral ingestion, respiratory inhalation, and dermal absorption, and the propensity for children to explore the world through taste and touch, exposure to pollutants has a heightened risk in youth. Their developing bodies make them more vulnerable as well, as they are less able to detoxify toxic chemicals.
Chemical exposure at an early age increases the body burden of harmful toxicants, many of which can stay in the body for a lifetime and escalates the risk for certain diseases such as cancer and Parkinson’s disease. Learn more about the hazards of pesticides for children’s health and how “Children and Pesticides Don’t Mix.” Beyond Pesticides promotes healthy environments for learning and recreation for children. Alternatives are available for schools and for creating sustainable parks that do not unnecessarily put children’s health at risk. Make The Safer Choice to avoid hazardous home, garden, community, and food use pesticides to protect children as they grow and develop.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Macheka, L. et al. (2024) Exposure to pesticides, persistent and non − persistent pollutants in French 3.5-year-old children: Findings from comprehensive hair analysis in the ELFE national birth cohort, Environment International. Available at: https://www.sciencedirect.com/science/article/pii/S0160412024004677.
