Toxic Effects of Particulate Matter Derived from Dust Samples Near the Dzhidinski Ore Processing Mill, Eastern...

Ambient particulate matter (PM) is associated with increased mortality and morbidity, an effect influenced by the metal components of the PM. We characterized five sediment samples obtained near a tungsten-molybdenum ore-processing complex in Zakamensk, Russia for elemental composition and PM toxicity with regard to pulmonary, vascular, and neurological outcomes. Elemental and trace metals analysis of complete sediment and PM₁₀ (the respirable fraction, < 10 µm mass mean aerodynamic diameter) were performed using inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS). Sediment samples and PM₁₀ consisted largely of silicon and iron and silicon and sodium, respectively. Trace metals including manganese and uranium in the complete sediment, as well as copper and lead in the PM₁₀ were observed. Notably, metal concentrations were approximately 10 × higher in the PM₁₀ than in the sediment. Exposure to 100 µg of PM₁₀ via oropharyngeal aspiration in C56BL/6 mice resulted in pulmonary inflammation across all groups. In addition, mice exposed to three of the five PM₁₀ samples exhibited impaired endothelial-dependent relaxation, and correlative analysis revealed associations between pulmonary inflammation and levels of lead and cadmium. A tendency for elevated cortical ccl2 and Tnf-α mRNA expression was induced by all samples and significant upregulation was noted following exposure to PM₁₀ samples Z3 and Z4, respectively. Cortical Nqo1 mRNA levels were significantly upregulated in mice exposed to PM₁₀ Z2. In conclusion, pulmonary exposure to PM samples from the Zakamensk region sediments induced varied pulmonary and systemic effects that may be influenced by elemental PM composition. Further investigation is needed to pinpoint putative drivers of neurological outcomes.