Work

Urinary excretion of H2S methylation metabolites in oil refinery workers

Year: 2024

Type: article

Abstract: Hydrogen sulfide (H 2 S) is a toxic gas emitted through natural and anthropogenic activities. Chronic exposure to inhaled H 2 S at low sub-toxic levels is common among workers in oil refineries and may have important health implications. Inhaled H 2 S can be oxidized to thiosulfate or methylated to dimethylsulfide (DMS) which can be methylated to the novel human metabolite trimethylsulfonium (TMS) or oxidized to dimethylsulfoxide (DMSO) but the extent of methylation of inhaled H 2 S is currently unknown in humans. A total of 80 participants were recruited of which 40 were workers in an oil refinery in Kurdistan region, Iraq including those working in close contact with the facility area where H 2 S was measured at 1.5–5.0 mg m −3 , and 40 controls living in a nearby city with no detectable H 2 S or perceptible odor (<0.1 mg m −3 ). A total of 240 urine samples were measured for multiple H 2 S-related metabolites. DMSO was consistently found in all urine samples with concentrations generally within the range of 1.0–10 µM. Although these concentrations were 10–100-fold higher than TMS urinary levels, clear correlation between DMSO and TMS was observed (r s 0.55, P < 0.0001), which supports DMS as common precursor. DMSO urinary levels were elevated in the oil refinery workers in close contact with the facilities (5.0 vs. 3.3 µM, P 0.03), but TMS was unaltered (0.13 vs. 0.14 µM, P 0.68). Overall, the results suggest that the investigated methylation metabolites are not sufficiently sensitive to low occupational exposure levels of inhaled H 2 S. • First investigation of the response of H 2 S-methylation metabolites to inhaled H 2 S in humans. • Total 240 urine samples were collected (120 from oil refinery workers and 120 from controls). • Dimethylsulfoxide (DMSO) was slightly elevated in oil refinery workers (3.3 vs. 5.0 µM), P 0.03. • Trimethylsulfonium (TMS) did not show a response to occupational H 2 S exposure. • H 2 S detoxification via methylation is limited at occupational exposure levels in humans.

Source: Toxicology Letters

DOI: 10.1016/j.toxlet.2024.09.007

Authors: Mamoon Q. Salih, Lorenz Steiner, Walter Goessler, Jawameer R. Hama, Bassam Lajin

Institutions: University of Graz, Aarhus University

Language: English

Topic: Sulfur Compounds in Biology

Subfield: Biochemistry

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $4,150