Assessment of additional health risk for men caused by the pituitary-gonadal axis deregulation under long-term combined exposure to airborne metals in fine- and ultradispersed particles (PM2.5 and smaller)

Long-term exposure to a mixture of airborne metals (lead, chromium, cobalt, nickel, copper, and others) in PM2.5 and smaller creates persistent exposure in residential areas in close proximity to industrial enterprises. Its effects on the pituitary- gonadal (PG) axis, the key spermatogenesis regulatorin men, have been studied only fragmentarily. It is necessary to analyze pathogenesis of the axis destabilization upon exposure to these particles considering their composition in order to quantify the additional reproductive risk and raise effectiveness of male infertility prevention. We examined 255 men; among them, 139 lived in an area exposed to industrial emissions with metals in PM2.5and smaller (cobalt, manganese, nickel, lead, chromium, and copper) and 116 were unexposed. Metals and fin-dispersed particles were identified in ambient air, whole blood, supernatant, and solid residue (ICP-MS); the PG axis hormones, in blood serum. Statistical analysis (Statistica 12.5) included logistic regression and additional risk calculation. The PM2.5 and smaller particles accounted for 71.3 % in the analyzed area exposed to emission form a metallurgical plant (2023–2025). Overall, their proportion exceeded the safe level by 2.1 times and the reference group indicator by 3.3 times (р = 0.0001). Ni, Pb, Mn, Cr, Cu, and Со were identified in the analyzed particles (Cu, Ni, up to 73 % of the РМ1 mass; Ni, Cr, up to 27 % of the РМ2.5 mass). Exposure to the sum of РМ2.5 and smaller particles amounted to 0.022 mg/(kg∙day) (65 % of the total exposure to suspended particles). Levels of the analyzed metals in blood and its fractions were higherin the exposed men against the reference group and the reference levels by up to 7.0 times (р = 0.0001–0.011). We found hypersecretion of the luteinizing hormone (up to 1.4 times, р = 0.038), associated with Cr, Cu, Со in solid blood residue, and a decline in free testosterone (by 1.5 times, р = 0.015), associated with Ni and Cr. The additional reproductive risk induced by the PG axis deregulation was 25.5 times higher than the permissible level (‘high’ risk). Long-term exposure to Ni, Cr, Mn, Cu, Co in РМ2.5 and smaller destabilizes the PG axis creating a high additional risk of male infertility by disrupting hormonal control of spermatogenesis. To objectively assess these risks and raise effectiveness of measures aimed at their mitigation, it is advisable to include detailed elemental analysis of fine- and ultradispersed ambient particles in residential areas in monitoring and biomonitoring programs.