Biomonitoring of Silver in Children and Adolescents from Alcalá de Henares (Spain): Assessing Potential Health Risks from Topsoil Contamination

This study assessed exposure to silver (Ag) in children and adolescents living in Alcalá de Henares, an urban-industrial city in the Madrid Region (Spain), in light of the growing use of Ag in consumer and medical products. Scalp hair was collected from 120 children (6-9 years; 70 females) and 97 adolescents (13-16 years; 68 females) permanently residing in the city, and Ag concentrations were determined by inductively coupled plasma mass spectrometry under strict quality control. In parallel, 97 topsoil samples from urban parks were analysed to evaluate potential environmental sources, and risks of non-carcinogenic exposure via ingestion and dermal routes were characterised. Median Ag levels (µg/g) were 0.1205 in girls and 0.0892 in boys among children, and 0.1057 and 0.0387 among adolescent females and males, respectively. No significant differences were observed between age groups (<i>p</i> = 0.153), but females showed consistently higher levels than males. Proposed reference intervals (CI-PP95) were 0.2866-0.5383 µg/g for children and 0.5248-3.0795 µg/g for adolescents. Hazard quotients for soil exposure were below unity, indicating minimal health risk. Overall, Ag exposure in Alcalá's youth was low and consistent with background levels in non-occupationally exposed populations. The higher values found in some female adolescents likely reflect lifestyle-related sources. These results provide the first local reference values for Ag in hair of Spanish children and adolescents, offering a baseline for future biomonitoring and temporal trend analyses.