Abstract
<jats:p>Inductively coupled plasma mass spectrometry (ICP–MS) was used to measure 24 elements in occipital scalp hair from 134 adults living in Campania, southern Italy (67 women, 67 men; age range 20–72 yr). Continuous models were restricted to the ten elements detected in at least 70% of adults: Al, Ba, Ca, Cr, Cu, K, Mg, Pb, Se and Zn. Multivariable log-linear models with HC3-robust standard errors adjusted for sex, age, fish consumption, medication and supplement use, current and passive smoking, hair treatments, cosmetic product use, tap-water use, occupational/environmental risk and sample mass, with multiple testing controlled by Benjamini–Hochberg false discovery rate (FDR) correction. Ca (median 1279.7g/g), Zn ( 153.5g/g), Mg ( 101.7g/g), K ( 14.8g/g) and Cu ( 13.9g/g) dominated the elemental profile. Pb had a median of 0.81g/g but an extreme right tail reaching 887.1g/g; Cd was detected in only 22.4% of adults, with a population median of zero. The most reproducible pattern was lower hair concentrations in males for Ca (Δ=−61.6%, q&amp;lt;0.001), Mg (Δ=−52.2%, q&amp;lt;0.001), Cu (Δ=−37.7%, q=0.003), Cr (Δ=−33.0%, q=0.011) and Zn (Δ=−23.9%, q=0.011). Sample mass remained inversely associated with Mg and Zn, indicating a potential analytical or censoring-related effect requiring quality-control attention. No fish, medication, supplement, smoking, tap-water or environmental-risk predictor survived FDR correction. An exploratory territorial display used medians for Al, Cr, Fe, Mn, Pb and Zn, and detection frequencies for the low-detection elements As, Cd and V, to visualize potential sentinel patterns. Exploratory unsupervised clustering separated a large mineral-enriched profile from a smaller mineral-depleted profile and, in a three-cluster sensitivity analysis, isolated a four-participant high-Pb/high-Ba sentinel subgroup; however, residual clustering after adjustment for sex, age, hair-care variables and sample mass was weak. These findings support hair biomonitoring as a screening tool in mixed-exposure regions and align with recent European calls for harmonised human biomonitoring, provided that sex, robust territorial aggregation, sample mass, non-detects, outliers and external contamination are handled explicitly.</jats:p>