Chemistry & Photochemistry of Airborne Industrial Dust: Human Health & Environmental Implications

Details

• Personal Author:
  Das MC
• Description:
  Industrial dust is one of the major sources of anthropogenic aerosols in the atmosphere, particularly in the vicinity of any manufacturing site. These particles are known to pose a severe risk to the health of nearby residents and workers. Although inhalation is the primary exposure pathway to dust, the amount of dust that gets into their respiratory system depends significantly on the size of the particles. The deep lung regions can be reached by dust particles with an aerodynamic diameter of less than 4 micrometers, although bigger particles may be filtered in the airway and cleared to the gastrointestinal tract (GIT). However, we only know a little about the impact of inhaled dust on human organs and the gut microbiota despite the critical necessity of this knowledge. In this thesis work, we attempted to address this issue by assessing the toxicity of coal and uranium mine dust based on their capacity to leach metals and non-metals into human body fluids. Uranium mine dust has been identified as one of the major health hazards that can cause cardiovascular and metabolic problems if inhaled. Prior studies have mostly concentrated on what happens to inhaled dust particles (<4 µm) once they reach the lungs. In this study, we investigated the uranium solubility from airborne dust and sediments in two simulated gastrointestinal fluids; Simulated Gastric Fluid (SGF) and Simulated Intestinal Fluid (SIF). For this purpose, samples were collected from nearby two uranium mines in the Grand Mining District (GMD) of New Mexico. As opposed to sediment samples from the St. Anthony Mine, which favored higher solubility in the SGF solution, Jackpile mine dust samples favored higher solubility in the SIF solution. Our results highlighted that mine dust rich in the minerals andersonite, tyuyamunite, and/or autunite exhibits more uranium dissolution in the SIF solution than in the SGF solution. These conclusions were further confirmed by the computational calculations performed using thermodynamic model PHREEQC. Additionally, we examined the influence of kaolinite and microcline since they were present in several collected samples. Kaolinite enhances mineral dissolution in SIF, except for andersonite, as evidenced by the fact that it lowers the ratio of dissolved uranium in SGF to SIF. For all of the investigated uranium minerals, the ratio of dissolved uranium in SGF to SIF drops with the addition of microcline. Based on computational analysis, the most common oxidation state of dissolved uranium was shown to be U(VI). The results of the experimental observations and the geochemical calculations done with PHREEQC are in agreement. As a result, this study sheds light on the mineralogy-controlled toxicological evaluation of inhaled dust that contains uranium and cleared into the gastrointestinal system. Exposure to respirable coal mine dust (RCMD) poses a health risk to the mining industry that contributes to several health problems, including coal worker pneumoconiosis (CWP). Given the geographic concentration of coal workers' pneumoconiosis (CWP), it was always assumed that RCMD in the Appalachian region is more harmful than RCMD in other areas. The characteristics of RCMD and their connections to dust toxicity based on their geographic location have not yet been investigated. We gathered samples from the Appalachian and Rocky Mountain regions to assess the toxicity based on metal leeching capability in simulated lung fluids (SLFs). Additionally, diverse RCMD sources that could exist inside the same mine can have unique physicochemical characteristics raising the possibility of various health effects that have not been thoroughly researched. In light of this, we also look into the toxicity of RCMD from several sources, including coal seam, rock dust, host floor, and host roof from Intra and Inter-mines. In order to uncover any trends associated with geographic regions and/or mine-specific sources, this investigation intends to quantify the metal leaching in the lung fluid and correlate that with the in-vitro immune responses. According to our findings, Si and Al are the most dissolved metals along with trace amounts of other metals, including Fe, Sr, Ba, and Pb. However, no patterns were discovered that would suggest a dependence on geographic location. The floor and roof dust dissolved the most metal, whereas the coal seam and rock dust dissolved the least amount of metal. Results from in-vitro tests indicated that floor and roof dust samples significantly impacted cell viability, indicating increased toxicity. The pro-inflammatory response may influence the development of pneumoconiosis and other lung illnesses in epithelial and macrophage cells. In addition to having an adverse effect on human health, industrial dust can also have impact on our climate. Atmospheric processing of industrial dust can contribute to the bioavailable Fe production that affecting primary productivity. The majority of previous research has been on Fe-containing mineral dust as a source of dissolved Fe to ocean life. Therefore, in the current work, we investigated coal fly ash (CFA) as a source of bioavailable iron. We conducted dissolution tests in low- and high-flux environments using spectroscopic methods such as infra-red, UV-vis, XRD, mass spectroscopy, etc. The nitric acid dissolution experiments were carried out in atmospherically suitable conditions. Further, having the increased CFA distributions in industrialized areas, engineered nanomaterials may be combined with them. Therefore, we investigated the impact of an engineered nanoparticle, titanium dioxide (TiO2), on the CFA's ability to leach out the iron. We performed tests by mixing CFA with both rutile and anatase crystal phases. Our results reveal that titanium enhances iron mobility from the CFA, regardless of whether titanium is added externally or present naturally in the sample. This research will therefore provide us with crucial, as of yet unexplored, knowledge on CFA as a source of bioavailable iron. Overall, the current research work reports the mineralogy-controlled impact of industrial dust on environmental processes and human health. The physicochemical properties of these manufactured particles can be linked to their extent of dissolution and, thus, their influence on biological and ecological systems. The results revealed in this thesis work will be used to develop risk assessment models to identify miners who may eventually develop lung illnesses by better comprehending the consequences of inhaled particles, the consequent cellular toxicity, and long-term health effects. Further, the data reported on coal fly ash mixed with engineered nanoparticles will be used to better understand global iron mobilization and predict biomass production in the ocean. [Description provided by NIOSH]
• Subjects:
  Aerosols Dust Environmental Pollution Metals Occupational Health Safety
• Keywords:
  Coal Dust Environmental Contamination Industrial Dusts Metal Dusts Nanoparticles Particle Aerodynamics Respirable Dust
• Publisher:
  New Mexico Institute of Mining and Technology
• Document Type:
  Text
• Funding:
  Contract
• Genre:
  Thesis
• Place as Subject:
  New Mexico ; OSHA Region 6
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-134
• NIOSHTIC Number:
  nn:20068704
• Citation:
  Socorro, NM: New Mexico Institute of Mining and Technology, 2023 Feb; :1-134
• Federal Fiscal Year:
  2023
• Performing Organization:
  New Mexico Institute of Mining and Technology
• Peer Reviewed:
  False
• Start Date:
  20190915
• Source Full Name:
  Chemistry & photochemistry of airborne industrial dust: human health & environmental implications
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:218e5b4092986d1f8f12cc741e9dfb076cd23316a275342dc97b732ad8e644f21b99d9074997a0c2a85ee0e9bcae0165a5fd7a65702b1edc0d921a6191307e96
• Download URL:
  https://stacks.cdc.gov/view/cdc/207291/cdc_207291_DS1.pdf
• File Type:
  [PDF - 6.62 MB ]