Serum trace metals across environmental-pressure strata in Campania, Italy (SPES): a population-based cross-sectional biomonitoring study

BACKGROUND AND OBJECTIVES: We characterized fine-scale geographic variation in serum trace metals across Campania (southern Italy). MATERIALS AND METHODS: In 2016-2017, the SPES programme sampled residents aged 20-49 years from municipal registries across Campania. Municipalities were stratified using an environmental-pressure index into three broad impact strata: high-impact, medium-impact and low-impact. For higher spatial resolution, municipalities were also grouped into 21 predefined municipal clusters. We measured 20 serum trace metals by ICP-MS and estimated age- and sex-adjusted geometric mean ratios (GMRs) comparing each stratum or cluster with the study-wide geometric mean. RESULTS: Of 4205 enrolled participants, 4188 were included. Medium-impact areas showed higher mercury (GMR 1.87, 95% CI 1.73-2.02) and antimony (1.95, 1.71-2.23) relative to the cohort average. At the municipal-cluster scale, the Irno Valley clusters around the Fonderie Pisano foundry (Baronissi-Pellezzano and Salerno) had about six-fold higher mercury (GMR 5.71 and 6.10) and about three-fold higher antimony (3.45 and 2.93), whereas the Valle del Sabato cluster showed about ten-fold higher antimony (GMR 10.5) and about seven-fold higher nickel (7.16) and cadmium (7.67). CONCLUSIONS: Overall serum metal concentrations were broadly comparable with European general-population ranges, but pronounced small-area heterogeneity indicates localized hotspots that provincial or regional averages can obscure.