Everyday exposures: feasibility of community-based trace metal monitoring using non-invasive bio-sampling in children’s environments, a pilot study

Children are uniquely vulnerable to environmental pollution due to their developing physiology, distinct behaviours, and higher exposure per body mass, and have limited influence over how their environments are designed and managed. However, the real-world feasibility of integrating non-invasive biomonitoring with community-sourced environmental sampling in children’s everyday settings remains under-evaluated. The absence of validated, field-feasible biomonitoring methods for use in schools and homes, limits the early detection of harmful exposures and constrains the development of routine paediatric environmental surveillance. This pilot study evaluated the feasibility of non-invasive bio-sampling to assess trace-metal exposure in 13 UK schoolchildren. Paired urine and exhaled breath condensate (EBC) samples, EBC being a condensed fraction of exhaled respiratory droplets that may reflect airway-level exposure, were collected alongside drinking water and soil from participants’ school and home environments. All samples were analysed for multiple trace elements using inductively coupled plasma mass spectrometry. To relate internal and external measures, Enrichment factors (EFs), were calculated as the ratio of metal concentrations in biological matrices relative to corresponding environmental sources. Despite small sample sizes, meaningful trends emerged. Elevated zinc and copper levels in tap water corresponded to higher urinary concentrations, suggesting urine is a sensitive matrix for waterborne exposure. In contrast low EFs in EBC relative to soil highlight matrix-specific limitations in using soil as a proxy for inhaled exposure in this matrix. The study demonstrates the practical and ethical suitability of non-invasive biomonitoring in paediatric populations, reinforcing the need for improved standardisation and comprehensive metadata collection. Findings support the potential value of integrating non-invasive methods into larger environmental health surveillance efforts involving children. This work contributes a scalable model for child-focused environmental health research that bridges scientific-data with social-justice, environmental education and equity.