Dose- and Time-Dependent Effects of Different Nickel-Based Thermal Spray Coating Aerosols on Lung Toxicity Using an Animal Inhalation Model

Details

• Personal Author:
  Afshari A ; Antonini JM ; Cumpston JB ; Cumpston JL ; Kashon ML ; Kodali VK ; Lee E ; Leonard HD ; McKinney W ; Meighan TG ; Moore R ; Zeidler-Erdely AD
• Description:
  Background and Purpose: Thermal spray coating is an emerging occupational process that applies molten metal under pressure onto a surface as a protective coating. Information about the potential health effects and the physio-chemical properties of the aerosols generated during this process are limited. Methods: A thermal spray coating generator and inhalation exposure system has been developed to perform animal studies to simulate workplace exposures. Male Sprague-Dawley rats were exposed to three different concentrations of aerosols generated from electric arc wire- thermal spray coating using two nickel (Ni)-based consumable wires- PMET885 and PMET876. Control animals were exposed to filtered air. Total cumulative target concentrations [exposure concentration (C; mg/ m3) x exposure time (T; hr)] for the exposure period were: (1) HIGH-400 mg (25 mg/m3 x 4 hr/d x 4 d); (2) MIDDLE-80 mg (5 mg/m3 x 4 hr/d x 4 d); (3) LOW-16 mg (4 mg/m3 x 4 hr/d x 1 d). At 4 and 30 d after the last exposure, bronchoalveolar lavage (BAL) was performed on the right lung and a histopathological analysis was performed on the left lung to assess lung toxicity. Animal body weights were measured throughout the 30-d post-exposure period to assess general health status of the exposed animals. Results: The metal composition of each aerosol was determined by ICP-AES: PMET885 (97% Ni, 2% Al) and PMET876 (56% Ni, 17% Cr, 17% Mo, 5% Fe, 3% Mn). The generated particles were complex metal oxides arranged as chain-like agglomerates with similar mass median diameters of 316 (PMET885) and 367 nm (PMET876). Inhalation exposure to both PMET885 and PMET876 at the HIGH concentration caused a significant loss in body weight compared to the corresponding air controls as soon as 3 and 2 d after the start of the exposure, respectively. Even though the animals in both groups started to gain weight post-exposure, they still weighed significantly less than controls at each time point assessed. Inhalation to both aerosols at the MIDDLE and LOW concentrations had no effect on body weight gain at any time point during and after exposure compared to controls. At all three exposure concentrations and at both 4 and 30 d after the last exposure, BAL fluid lactate dehydrogenase (LDH; lung cell injury marker) and total BAL cells recovered (index of inflammation) were significantly elevated for the PMET885 group compared to air control. BAL fluid LDH was significantly elevated at all three concentrations at 4 d but only at the HIGH concentration after exposure to PMET876 aerosol at 30 d compared to air control, whereas the total BAL cells recovered were significantly elevated at both time points for all three exposure concentrations. Histopathological lung changes after inhalation to the HIGH concentration for both aerosols included alveolar histiocytic infiltration, alveolar interstitial fibrosis, bronchioloalveolar chronic-active inflammation, bronchiolar goblet cell metaplasia, and perivascular mixed cell infiltration. Alveolar interstitial fibrosis was observed in association with inflammatory foci after exposure to the PMET885 aerosol but not PMET876. The incidence of fibrosis in the PMET885 group was higher at 4-d post-exposure compared to 30-d, suggesting the fibrous change was partially reversible and was indicative of a less mature fibrogenesis. In addition, goblet cell metaplasia was observed for both aerosols at 4-d after exposure to the HIGH concentration but not at 30-d. The absence of this change at 30-d after exposure likely indicated a recovery of the bronchiolar epithelium. Inhalation exposure to two different Ni-based thermal spray coating aerosols caused significant lung toxicity and body weight loss in a dose-and time-dependent manner. Conclusions: In summary, the PMET885 aerosol that was composed of nearly all Ni (97%) was more pneumotoxic than the PMET876 aerosol that had significant amounts of Cr, Mo, Fe, and Mn besides Ni (56%) in its metal profile. Results of this animal inhalation study indicated that different Ni-based thermal spray coating aerosols can be quite toxic to the lungs, and the varied lung responses observed were likely dependent of the metal composition of the consumables used. [Description provided by NIOSH]
• Subjects:
  Aerosols Laboratories Nickel Occupational Health Respiratory System Safety
• Keywords:
  Histopathology Inhalation Laboratory Animals Protective Coatings Toxic Effects
• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  North Carolina ; OSHA Region 3 ; OSHA Region 4 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  198
• NIOSHTIC Number:
  nn:20069346
• Citation:
  Toxicologist 2024 Mar; 198(S1):414
• CAS Registry Number:
  Nickel (CAS RN 7440-02-0)
• Federal Fiscal Year:
  2024
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 63rd Annual Meeting & ToxExpo, March 10-14, 2024, Salt Lake City, Utah
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:654cf335640ccce6d04d62ba2aa707b25d263306fa7f69ac62029b620834408c5e677972cb11ee84d5c0ec0783d26dc410dcb7df76edc93c514e16cf9f351ee0
• Download URL:
  https://stacks.cdc.gov/view/cdc/207844/cdc_207844_DS1.pdf
• File Type:
  [PDF - 541.18 KB ]