Human inhalation exposure to ethylene glycol

Area of Science:

• Toxicology
• Environmental Health
• Metabolism Studies

Background:

• Ethylene glycol (EG) is an industrial chemical with known toxicity.
• Understanding EG metabolism and the toxicokinetics of its metabolites, glycolic acid (GA) and oxalic acid (OA), is crucial for risk assessment.
• Previous studies have indicated potential risks associated with EG metabolite accumulation.

Purpose of the Study:

• To investigate the toxicokinetics of inhaled (13)C-labeled ethylene glycol ((13)C(2)-EG) and its metabolites in humans.
• To quantify the excretion of (13)C(2)-EG, (13)C(2)-glycolic acid ((13)C(2)-GA), and (13)C(2)-oxalic acid ((13)C(2)-OA) in urine.
• To assess the potential health risks associated with workplace EG exposure based on metabolite levels.

Main Methods:

• Two male volunteers inhaled (13)C(2)-EG for 4 hours.
• Plasma and urine samples were collected and analyzed using gas chromatography-mass spectrometry (GC-MS).
• Quantification of (13)C(2)-EG, (13)C(2)-GA, (13)C(2)-OA, and background levels of EG, GA, and OA.

Main Results:

• Maximum plasma concentrations of (13)C(2)-EG and (13)C(2)-GA were measured, with corresponding half-lives determined.
• Urinary excretion of (13)C(2)-EG, (13)C(2)-GA, and (13)C(2)-OA was quantified over 28 hours.
• (13)C(2)-GA and (13)C(2)-OA excretion represented a small fraction of background urinary levels.

Conclusions:

• The toxicokinetic analysis indicates low risk of adverse effects from EG metabolites at typical workplace exposure levels.
• Inhaled ethylene glycol exposure at the German MAK-value is unlikely to lead to harmful accumulation of glycolic acid and oxalic acid.
• These findings support current occupational exposure limits for ethylene glycol.