Literature Review and Experimental Studies to Evaluate the Bioaccessibility and Dermal Penetration of Inorganic Pb Compounds for Occupational Risk Assessment

Details

• Personal Author:
  Maier A ; Niemeier, R. Todd ; Reichard JF
• Description:
  Evaluations were conducted to better understand the potential for dermal penetration of Pb compounds in workplace settings. This included 1) a rapid review of published data for estimation of key percutaneous absorption parameters (Kp, diffusion rates), 2) a dermal bioaccessibility study of 4 Pb compounds (Pb acetate (PbA), Pb Nitrate (PbN), Pb oxide (PbO), Pb red oxide (PbRO)) based on dissolution in synthetic sweat (SS) at 2 pH values (5.3, 6.5); and 3) pilot studies to evaluate the potential for PbN to penetrate through human cadaver skin using Franz cells. Outcomes: 1) The literature review identified 4 Pb compounds PbA, PbN, PbO, Pb metal (PbM) with relevant data for occupational risk assessment. Diffusion rates for the pool of animal and human skin data ranged from 10-6 to 10-4 mg/cm2/h for water soluble Pb compounds (PbA, PbN) and 10-7 to 10-5 mg/cm2/h for insoluble Pb compounds (PbO, PbM). Kp values ranged from 10-7 to 10-5 cm/h for soluble Pb compounds. No Kp values were found for water insoluble Pb compounds (PbO, PbM). Study design and documentation was highly variable and only one study was conducted using guideline methods. 2) Dissolution in SS ranged from 25.0-39.0% for PbN and PbA and 0.06-3.6% for PbO and PbRO with a significant difference between pH values. 3) Pilot Franz cell studies were conducted under both infinite and finite dosing procedures with donor cell concentrations as high as 1,077 µg Pb ion/cm2 on skin for 24-72 hrs. The skin was washed after the experiment and Pb was determined in wash samples, skin (epidermis and dermis layers), and receptor fluid. Total recoveries ranged from 51-71%, with 39.5-47.2% in wash, 4.0-31.6% in skin. Pb was detected in the dermis layer (3.0-16.6%), suggesting a potential for systemic distribution. Pb was not detected in receptor fluid across three studies. In one study, PbN formed a precipitate in phosphate saline buffer (receptor fluid), which may have prohibited the penetration of Pb into the receptor and highlights the importance of considering the interactions of Pb ion interactions test buffers and biological fluids in experimental systems. Overall, these studies suggest that dermal penetration and absorption of inorganic Pb compounds are likely, but additional studies are needed for quantitative estimations of resulting impacts on systemic doses from skin contact exposures. [Description provided by NIOSH]
• Subjects:
  Acetates Animals Environmental Exposure Laboratories Lead Nitrates Occupational Health Safety Skin Skin Absorption
• Keywords:
  Dermal absorption; Lead; Lead compounds; Acetates; Nitrates; Oxides; Skin exposure; Skin absorption; Risk assessment; Animals; Laboratory animals; Exposure levels
• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OD - Office of the Director
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  186
• NIOSHTIC Number:
  nn:20064932
• Citation:
  Toxicologist 2022 Mar; 186(S1):276
• CAS Registry Number:
  Lead (CAS RN 7439-92-1)
• Federal Fiscal Year:
  2022
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 61st Annual Meeting & ToxExpo, March 27-31, 2022, San Diego, California
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:b2cff45f178484baaac411bd45adfcbe24685d482fe93dcf90e2c989df63b4438dd1ad28efdd6853801f032e669a048664c733cb4146126a721eaa25a5701c9f
• Download URL:
  https://stacks.cdc.gov/view/cdc/248906/cdc_248906_DS1.pdf
• File Type:
  [PDF - 222.43 KB ]