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

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.

Respirable Uranyl-Vanadate-Containing Particulate Matter Derived From a Legacy Uranium Mine Site Exhibits Potentiated Cardiopulmonary Toxicity.

Exposure to windblown particulate matter (PM) arising from legacy uranium (U) mine sites in the Navajo Nation may pose a human health hazard due to their potentially high metal content, including U and vanadium (V). To assess the toxic impact of PM derived from Claim 28 (a priority U mine) compared with background PM, and consider the putative role of metal species U and V. Two representative sediment samples from Navajo Nation sites (Background PM and Claim 28 PM) were obtained, characterized in terms of chemistry and morphology, and fractioned to the respirable (≤ 10 µm) fraction. Mice were dosed with either PM sample, uranyl acetate, or vanadyl sulfate via aspiration (100 µg), with assessments of pulmonary and vascular toxicity 24 h later. Particulate matter samples were also examined for in vitro effects on cytotoxicity, oxidative stress, phagocytosis, and inflammasome induction. Claim 28 PM10 was highly enriched with U and V and exhibited a unique nanoparticle ultrastructure compared with background PM10. Claim 28 PM10 exhibited enhanced pulmonary and vascular toxicity relative to background PM10. Both U and V exhibited complementary pulmonary inflammatory potential, with U driving a classical inflammatory cytokine profile (elevated interleukin [IL]-1ß, tumor necrosis factor-α, and keratinocyte chemoattractant/human growth-regulated oncogene) while V preferentially induced a different cytokine pattern (elevated IL-5, IL-6, and IL-10). Claim 28 PM10 was more potent than background PM10 in terms of in vitro cytotoxicity, impairment of phagocytosis, and oxidative stress responses. Resuspended PM10 derived from U mine waste exhibit greater cardiopulmonary toxicity than background dusts. Rigorous exposure assessment is needed to gauge the regional health risks imparted by these unremediated sites.

Microbial desalination cell with sulfonated sodium poly(ether ether ketone) as cation exchange membranes for enhancing power generation and salt reduction.

Microbial desalination cell (MDC) is a bioelectrochemical system capable of oxidizing organics, generating electricity, while reducing the salinity content of brine streams. As it is designed, anion and cation exchange membranes play an important role on the selective removal of ions from the desalination chamber. In this work, sulfonated sodium (Na+) poly(ether ether ketone) (SPEEK) cation exchange membranes (CEM) were tested in combination with quaternary ammonium chloride poly(2,6-dimethyl 1,4-phenylene oxide) (QAPPO) anion exchange membrane (AEM). Non-patterned and patterned (varying topographical features) CEMs were investigated and assessed in this work. The results were contrasted against a commercially available CEM. This work used real seawater from the Pacific Ocean in the desalination chamber. The results displayed a high desalination rate and power generation for all the membranes, with a maximum of 78.6±2.0% in salinity reduction and 235±7mWm-2 in power generation for the MDCs with the SPEEK CEM. Desalination rate and power generation achieved are higher with synthesized SPEEK membranes when compared with an available commercial CEM. An optimized combination of these types of membranes substantially improves the performances of MDC, making the system more suitable for real applications.

Effect of PVC and iron materials on Mn(II) deposition in drinking water distribution systems.

Polyvinyl chloride (PVC) and iron pipe materials differentially impacted manganese deposition within a drinking water distribution system that experiences black water problems because it receives soluble manganese from a surface water reservoir that undergoes biogeochemical cycling of manganese. The water quality study was conducted in a section of the distribution system of Tegucigalpa, Honduras and evaluated the influence of iron and PVC pipe materials on the concentrations of soluble and particulate iron and manganese, and determined the composition of scales formed on PVC and iron pipes. As expected, total Fe concentrations were highest in water from iron pipes. Water samples obtained from PVC pipes showed higher total Mn concentrations and more black color than that obtained from iron pipes. Scanning electron microscopy demonstrated that manganese was incorporated into the iron tubercles and thus not readily dislodged from the pipes by water flow. The PVC pipes contained a thin surface scale consisting of white and brown layers of different chemical composition; the brown layer was in contact with the water and contained 6% manganese by weight. Mn composed a greater percentage by weight of the PVC scale than the iron pipe scale; the PVC scale was easily dislodged by flowing water. This research demonstrates that interactions between water and the infrastructure used for its supply affect the quality of the final drinking water.