{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T04:20:07Z","timestamp":1787804407463,"version":"build-2784847793"},"reference-count":59,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T00:00:00Z","timestamp":1787616000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Xenobiotics","JoX"],"abstract":"<jats:p>Scalp hair offers a non-invasive matrix for retrospective paediatric biomonitoring, although interpretation is complicated by endogenous incorporation, exogenous deposition and element-specific analytical detectability. We characterised B, Ca, Co, Fe, Li, Mg, Mo, Ni and Se in archived scalp hair collected in 2001 from 120 children aged 6\u20139 years and 97 adolescents aged 13\u201316 years residing in urban\u2013industrial Alcal\u00e1 de Henares, Spain. Samples were analysed in 2025 by ICP\u2013MS using a common quality-controlled analytical workflow, with left-censored observations evaluated using censoring-aware methods. B and Li were highly censored (89.2\u201394.8% and 86.7\u201399.0%, respectively), whereas Fe, Mg, Mo and Se were consistently quantified. Adolescents showed higher median Ca (325 vs. 168 \u00b5g g\u22121; q = 1.43 \u00d7 10\u22129), Mg (24.0 vs. 9.05 \u00b5g g\u22121; q = 8.91 \u00d7 10\u221219) and Ni (0.169 vs. 0.0597 \u00b5g g\u22121; q = 2.10 \u00d7 10\u22125), but lower Fe (5.16 vs. 7.54 \u00b5g g\u22121; q = 2.28 \u00d7 10\u221211), Co and Mo than children. Sex-associated differences were also observed for several elements, although their magnitude and detectability varied between age strata. Residential heterogeneity was strongest among adolescents: median Ca in the mixed residential\u2013industrial Zone IV was 967 \u00b5g g\u22121 compared with 232\u2013385 \u00b5g g\u22121 in Zones I\u2013III (q = 2.75 \u00d7 10\u221212), while median Mg was 113 versus 18.8\u201324.3 \u00b5g g\u22121 (q = 2.26 \u00d7 10\u22126). These specimens, collected in 2001, stored dry in paper envelopes for approximately 24 years, and analysed together in the 2025 ICP\u2013MS campaign, provide a distinctive historical paediatric biomonitoring baseline from a well-defined Spanish urban\u2013industrial population. The findings support scalp hair as a screening-level matrix for investigating population patterns across developmental stage, sex and residential setting, while not supporting its use as a direct measure of nutritional status, internal dose or health risk.<\/jats:p>","DOI":"10.3390\/jox16050157","type":"journal-article","created":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T08:00:48Z","timestamp":1787644848000},"page":"157","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Paediatric Scalp-Hair Biomonitoring of Nutritionally Relevant and Mixed-Source Elements in Urban\u2013Industrial Spain"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5690-5445","authenticated-orcid":false,"given":"Antonio","family":"Pe\u00f1a-Fern\u00e1ndez","sequence":"first","affiliation":[{"name":"Area of Legal and Forensic Medicine, Department of Surgery, Medical and Social Sciences, Faculty of Medicine and Health Sciences, University of Alcal\u00e1, Crta. Madrid-Barcelona Km, 33.6, 28871 Alcal\u00e1 de Henares, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0908-8286","authenticated-orcid":false,"given":"M. \u00c1ngeles","family":"Pe\u00f1a Fern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Department of Biomedical Sciences, Faculty of Pharmacy, University of Alcal\u00e1, Crta. Madrid-Barcelona Km, 33.6, 28871 Alcal\u00e1 de Henares, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-9124-5507","authenticated-orcid":false,"given":"Borja","family":"Mart\u00ednez-Alonso","sequence":"additional","affiliation":[{"name":"Department of Biomedical Sciences, Faculty of Pharmacy, University of Alcal\u00e1, Crta. Madrid-Barcelona Km, 33.6, 28871 Alcal\u00e1 de Henares, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4834-289X","authenticated-orcid":false,"given":"Rafael","family":"Moreno-G\u00f3mez-Toledano","sequence":"additional","affiliation":[{"name":"Area of Human Anatomy and Embryology, Faculty of Medicine and Health Sciences, University of Alcal\u00e1, Crta. Madrid-Barcelona Km, 33.6, 28871 Alcal\u00e1 de Henares, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-3428-7601","authenticated-orcid":false,"given":"Tom\u00e1s","family":"C\u00e1mara-Pastor","sequence":"additional","affiliation":[{"name":"Scientific Computation Research Institute (SCRIUR), University of La Rioja, 26006 Logro\u00f1o, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5530-1714","authenticated-orcid":false,"given":"Manuel","family":"Higueras","sequence":"additional","affiliation":[{"name":"Scientific Computation Research Institute (SCRIUR), University of La Rioja, 26006 Logro\u00f1o, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. Carmen","family":"Lobo-Bedmar","sequence":"additional","affiliation":[{"name":"Departamento de Investigaci\u00f3n Agroambiental, Madrid Institute for Rural, Agricultural and Food Research and Development (IMIDRA), Finca el Enc\u00edn, Crta. Madrid-Barcelona Km, 38.2, 28800 Alcal\u00e1 de Henares, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"125552","DOI":"10.1016\/j.envpol.2024.125552","article-title":"Metals and metalloids pollution levels, partitioning, and sources in the environmental compartments of a small urban catchment in Moscow megacity","volume":"367","author":"Kasimov","year":"2025","journal-title":"Environ. 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