Description of childen’s chemical exposome and possible determinants of exposure based on hair analysis

Background and Aim: Chemical exposure at young ages is associated with various diseases, and 25% of all deaths of children younger than 5 y/o are caused by exposure to unhealthy environment. Moreover, the specific physiology and behaviour of children, which differ significantly from adults, make them particularly vulnerable to chemical exposure. As a result, children exposure cannot be extrapolated from data obtained in adults and specific studies must be conducted on children. In the present study, hair samples were collected from 264 children inhabitants of Luxembourg aged below 13 y/o to investigate their chemical exposome and possible determinants of exposure. Methods: Each sample was analysed with a multi-residue method targeting 153 biomarkers, including 140 pesticides (persistent and non-persistent), 4 PCBs, 7 BDEs, and 2 bisphenols. Moreover, anthropometric parameters, information on diet, residence area and presence of pets at home were collected through self-reported questionnaires. Results: The number of compounds detected per sample ranged from 29 to 88 (median = 61). Twenty-three biomarkers were detected in ≥95% of the samples, including 13 in all samples (11 pesticides, BPA and BPS). Results showed higher exposure in younger children, and higher exposure to non-persistent pesticides in boys. Moreover, the results showed that diet (organic vs conventional), residence area, and living with pets at home are determinants of exposure. Conclusions: The present study demonstrates that children are exposed simultaneously to multiple pollutants from different chemical classes, and confirms that hair is well adapted to investigate children exposure. The presence of many persistent organic pollutants (POPs) in most children, despite their young age, strongly suggests that exposure to POPs is still ongoing. The results obtained here set the basis for further investigations to better understand the determinants of exposure to pollutants in children. Keywords: Chemical exposome; Determinants of exposure; Hair analysis; Biomonitoring; Children; Organic pollutants