Hydrogen Sulfide Poisoning

Sulfide poisoning is by inhalation of hydrogen sulfide gas, particularly in industrial or waste disposal sites, including sewers. The gas has a characteristic foul odour of rotten-eggs and has a very low odour threshold (0.03 ppm). H2S is unstable and is metabolized rapidly in the body making it difficult to detect in biological samples. In suspected acute or chronic exposure to H2S, blood specimens must be collected as soon as possible because of its rapid metabolism. H2S is metabolized into thiosulfate--- measurement of blood or urine thiosulfate concentration to the investigation of acute or chronic sulfide poisoning. To establish poisoning, sulfide concentrations in biological fluids should be in the range of 30-130 μg/L. Reference values for sulfide concentrations in biological fluids are <10 μg/L. Postmortem results after industrial accidents have shown blood sulfide concentrations of 0.9–3.8 mg/L. Specimen collection Specimens to be collected as follows:

1. Blood – 10 mL of anticoagulant blood (K-EDTA)

2. Urine – 20 mL, sterile plastic universal container.

3. Stomach contents – useful in postmortem examination of fatalities

4. Scene residues – useful for identification purposes.

Blood is the suitable specimen for fatal poisoning cases; while urine is suitable for survived cases after poisoning. Ideally, the biological samples should be refrigerated/freeze to prevent post-mortem H2S formation. Detection:

1. Headspace GC with Flame photometric detector

2. GC-MS: via derivatization of H2S

3. GC-MS: via derivatization of thiosulfate (a metabolite of H2S)

Christia-Lotter A et al. (2007). Fatal occupational inhalation of hydrogen sulfide. Forensic Sci Int 169: 206–209. Thiosulfate in human urine following minor exposure to hydrogen sulfide: implications for forensic analysis of poisoning | SpringerLink https://link.springer.com/article/10.1007/s11419-007-0033-7 Hydrogen Sulfide | Medical Management Guidelines | Toxic Substance Portal | ATSDR (cdc.gov)