Evaluation of the Role of Toxicological Data in Discriminating Between H2S Femoral Blood Concentration Secondary to Lethal poisoning and Endogenous H2S Putrefactive Production

Influence of blood thiosulfate produced by postmortem changes for the diagnosis of hydrogen sulfide poisoning in forensic autopsy

Background

Thiosulfate concentration in blood is an important indicator for the diagnosis of hydrogen sulfide poisoning. It may also be detected at high levels in postmortem decomposition cases.

Objectives

To determine the effect of postmortem decomposition on blood thiosulfate concentration and define precautions for diagnosing hydrogen sulfide poisoning based on thiosulfate concentration.

Methods

A total of 57 cadavers (37 males and 20 females) of non-hydrogen sulfide poisoning-related deaths that underwent forensic autopsy in our department between 2016 and 2019 were classified into the non-decomposed (19 cases), partially decomposed (19 cases), and severely decomposed (19 cases) groups based on forensic findings. Blood samples collected from each case were analyzed for thiosulfate concentration using liquid chromatography-tandem mass spectrometry.

Results

The mean concentration of thiosulfate detected in the blood was 70.9 (10.5-266.6) μmol/L in the severely decomposed group, 16.3 (0.1-52.7) μmol/L in the partially decomposed group, and 1.1 (0.1-3.6) μmol/L in the non-decomposed group. There was a statistically significant difference between each of the 3 groups (P < 0.01).

Conclusions

Previous studies have reported a blood thiosulfate concentration of >14 μmol/L in hydrogen sulfide poisoning cases and <4 μmol/L in normal cases. Thus, thiosulfate concentration is believed to have a significant impact on the diagnosis of hydrogen sulfide poisoning. This study revealed that postmortem decomposition produced thiosulfate in the blood, and the concentration of thiosulfate was often as high as that observed in cases of hydrogen sulfide poisoning-related death. In addition to cases of advanced decomposition, an increase in thiosulfate concentration was also observed in cases of partial decomposition. Therefore, when measuring thiosulfate concentration as an indicator of hydrogen sulfide poisoning, it is necessary to carefully consider the influence of decomposition.

Influence of Drugs and Toxins on Decomposition Dynamics: Forensic Implications

Drug and toxin-related deaths are common worldwide, making it essential to detect the postmortem concentration of various toxic substances at different stages of decomposition in a corpse. Indeed, determining the postmortem interval (PMI) and cause of death in an advanced stage of decomposed corpses has been a significant challenge in forensic investigations. Notably, the presence of drugs or toxins can have a significant impact on the microbial profile, potentially altering the succession of microbial communities and subsequent production of volatile organic compounds (VOCs), which, in turn, affect insect colonization patterns. This review aims to highlight the importance of investigating the interactions between drugs or toxins, microbial succession, VOC profiles, and insect behavior, which can provide valuable insights into forensic investigations as well as the ecological consequences of toxins occurring in decomposition. Overall, the detection of drugs and other toxins at different stages of decomposition can yield more precise forensic evidence, thereby enhancing the accuracy of PMI estimation and determination of the cause of death in decomposed remains.

A serial analysis of hydrogen sulfide poisoning: three group accidents

Hydrogen sulfide (H2S) is a powerful toxic gas in workplace incidents, and it poses a threat to colleagues or family members involved in rescues, leading to a "domino effect" of multiple deaths. In this report, we describe three incidents in which 10 people died, and we present the results of the analyses performed in different incidents, including paper pulp pit, sewer, and sewage well. We provide the macroscopic and morphological findings of ten victims, which include conjunctival hemorrhage, corneal erosion, pulmonary edema, and pulmonary hemorrhage. Additionally, we observed large amounts of waste paper pulp or black sludge in the upper and lower respiratory tracts or upper and lower gastrointestinal tracts of six victims. Furthermore, we conducted a toxicological examination of the victims' blood sulfide using an alkylation extraction approach combined with gas chromatography/mass spectrometry. The sulfide concentrations in the 10 victims ranged from 0.06 to 6.72 mg/L.

Hydrogen sulfide poisoning in forensic pathology and toxicology: mechanism and metabolites quantification analysis

Historically, hydrogen sulfide (H₂S) poisoning has extremely high and irreparable mortality. Currently, the identification of H₂S poisoning needs to combine with the case scene analysis in forensic medicine. The anatomy of the deceased seldom had obvious features. There are also a few reports about H₂S poisoning in detail. As a result, we give a comprehensive analysis of the related knowledge on the forensic aspect of H₂S poisoning. Furthermore, we provide the analytical methods of H₂S and its metabolite-which may assist in H₂S poisoning identification.

Decomposition kinetics and postmortem production of hydrogen sulfide and its metabolites

BACKGROUND

Hydrogen sulfide (H₂S), an endogenous gas, can also be generated from organics putrefaction. It is difficult for suspected cases of H₂S poisoning to determine whether H₂S in specimens is ingested by antemortem poisoning or generated from organics putrefaction. The aim of this study was to find the biomarkers of acute H₂S poisoning via comparing the concentrations of H₂S and its metabolites over time in specimens.

METHODS

The H₂S-spiked blood and blank blood group were established. The decomposition kinetics and the postmortem production of H₂S were studied due to organics putrefaction. The specimens were placed under 4 conditions of 37, 20, 4 and - 20 ℃. The content of H₂S in specimens was quantified by gas chromatography-mass spectrometry, and the contents of its metabolites (thiosulfate and trimethylsulfonium) were measured by liquid chromatography-mass spectrometry, and the variation of its concentration was evaluated.

RESULTS

In H₂S-spiked blood, H₂S decreased sharply in the initial stage at 37, 20 and 4 °C, and increased first and then decreased later; but it was relatively stable at - 20 °C. In spiked blood, thiosulfate was 9-fold higher than endogenous concentrations, which increased at first and then decreased during storage. Except for thiosulfate at 37 °C, H₂S and thiosulfate in blank blood both increased at first and then decreased in storage; but trimethylsulfonium (TMS) gradually decreased over time in both groups.

CONCLUSIONS

Thiosulfate is a reliable biomarker of acute H₂S poisoning at - 20℃ within 7 days. But H₂S, because of instability and volatility, is not an ideal poisoning marker. TMS is not an appropriate biomarker due to extremely low concentration in blood.

A Rare Case of Suicide by Ingestion of Phorate: A Case Report and a Review of the Literature

Phorate is a systemic organophosphorus pesticide (OP) that acts by inhibiting cholinesterases. Recent studies have reported that long-term low/moderate exposure to OP could be correlated with impaired cardiovascular and pulmonary function and other neurological effects. A 70-year-old farmer died after an intention ingestion of a granular powder mixed with water. He was employed on a farm for over 50 years producing fruit and vegetables, and for about 20 years, he had also applied pesticides. In the last 15 years, he used phorate predominantly. The Phorate concentration detected in gastric contents was 3.29 µg/mL. Chronic exposure to phorate is experimentally studied by histopathological changes observed in the kidney. In the light of current literature, our case confirms that there is an association between renal damage and chronic exposure to phorate in a subject exposed for years to the pesticide. Autopsies and toxicological analyses play a key role in the reconstruction of the dynamics, including the cause of the death.

Fatal poisoning of four workers in a farm: Distribution of hydrogen sulfide and thiosulfate in 10 different biological matrices

We evaluate the distribution of sulfide and thiosulfate (TS) in biological samples of four dairy farmers died inside a pit connected to a manure lagoon. Autopsies were performed 4 days later. Toxicological analyses of sulfide and TS were made using an extractive alkylation technique combined with gas chromatography/mass spectrometry (GC/MS). Autopsies revealed: multiorgan congestion; pulmonary edema; manure inside distal airways of three of the four victims. Sulfide concentrations were cardiac blood: 0.5-3.0 μg/mL, femoral blood: 0.5-1.2 μg/mL, bile: <0.1-2.2 μg/mL; liver 2.8-8.3 μg/g, lung: 5.0-9.4 μg/g, brain: 2.7-13.9 μg/g, spleen: 3.3-6.3 μg/g, fat: <0.1-1.5 μg/g, muscle: 2.6-3.5 μg/g. TS concentrations were cardiac blood: 2.1-4.9 μg/mL, femoral blood: 2.1-2.3 μg/mL, bile: 2.5-4.4 μg/mL, urine: <0.5-1.8 μg/mL; liver <0.5-2.6, lung: 2.8-5.4 μg/g, brain: <0.5-1.9 μg/g, spleen: 1.2-2.9 μg/g, muscle: <0.5-5.6 μg/g. The cause of death was assessed to be acute poisoning by hydrogen sulfide (H₂S) for all the victims. Manure inhalation contributed to the death of three subjects. The measurement of sulfide and TS concentrations in biological samples contributed to better understand the sequence of the events. Subjects 3 provided the highest concentration of sulfide in brain, thus, supporting the hypothesis of a rapid loss of consciousness and respiratory depression. One by one, the other farmers entered the pit in attempts to rescue the coworkers but collapsed. Despite the rapid death, subject 3 was the only one with TS detectable in urine. This could be due to differences in metabolism of H₂S.

Toxicological investigations in a fatal and non-fatal accident due to hydrogen sulphide (H2S) poisoning

Hydrogen sulphide (H₂S) is one of the most toxic natural gas and represents a not rare cause of fatal events in workplaces. We report here a serious accidental poisoning by hydrogen sulphide inhalation involving six sailors. Three of them died while the other three survived and were transported to the emergency room. No greenish discolouration of the body, that could be a feature of these type of deaths, was observed at autopsy. Given that blood and/or urine H₂S detection does not allow to discriminate if it is related to inhalation or to putrefactive processes, the determination of thiosulphate, H₂S main metabolite, is decisive. The succession of fatal events reported here can be rebuilt by toxicological data interpretation: the subject 1 died after a longer interval of time as demonstrated by the highest blood and urine thiosulfate concentrations; the subject 2 died after a short interval of time as showed by a lower blood and urine thiosulfate concentrations than subject 1; the subject 3 died almost immediately after H₂S inhalation since he showed the lowest blood thiosulfate concentration, and no trace of sulphide and thiosulfate was found in the urine.

Rapid Determination of H2S Poisoning in a Forensic Study Using a Novel Fluorescence Assay Based on Zn/Cu@BSA Nanoclusters

The quantitative determination of H2S in the blood can provide valid evidence for H2S poisoning through occupational exposure. However, known traditional methods for the detection of H2S in blood are time consuming, require complicated pretreatments, and have low sensitivity. In this paper, a new fluorescence sensing assay is proposed for the rapid detection of H2S poisoning in forensic cases based on bovine serum albumin (BSA)-stabilised zinc/copper (Zn/Cu) bi-metal nanoclusters (Zn/Cu@BSA NCs). The as-prepared Zn/Cu@BSA NCs probes have been characterised by UV-vis absorption and fluorescence spectroscopy. The fluorescence of Zn/Cu@BSA NCs can be quenched through specific interactions between HS−/S2− and the Zn2+/Cu2+ bi-metal ions. Under optimised conditions, the fluorescence sensing method was linear in the concentration range of 2.5 nM to 30 mM with 0.69 nM as the limit of detection. Moreover, the practical feasibility of this fluorescence sensing method has also been demonstrated by the analysis of mice blood samples containing different levels of sulfide and human blood samples from forensic cases of H2S poisoning. Compared with gas chromatography/mass spectrometry (GC/MS), this fluorescence sensing method is quite simple, straightforward, and can be accurate for the quantitative determination of H2S poisoning in a few minutes for forensic analysis. Overall, this is the first report of a bi-metal fluorescence sensing assay for detecting H2S poisoning directly in blood. This research may provide a new approach for forensic toxicologists to monitor poisoning by H2S using a fluorescence-sensing method.

A rapid evaluation of acute hydrogen sulfide poisoning in blood based on DNA-Cu/Ag nanocluster fluorescence probe

Hydrogen sulfide (H₂S) is a highly toxic gas as a cause of inhalational death. Accurate detection of H₂S poisoning concentration is valuable and vital for forensic workers to estimate the cause of death. But so far, it is no uniform and reliable standard method to measure sulfide concentrations in H₂S poisoning blood for forensic identification. This study introduces a fluorescence sensing technique into forensic research, in which a DNA-templated copper/silver nanocluster (DNA-Cu/AgNCs) fluorescence probe has been proposed to selective detection of S^2-. Under an optimized condition, the proposed method can allow for determination of S^2- in the concentration range of 10 pM to 1 mM with a linear equation: y = -0.432 lg[S^2-] + 0.675 (R² = 0.9844), with the limit of detection of 3.75 pM. Moreover, acute H₂S poisoning mouse models were established by intraperitoneally injected different doses of Na₂S, and the practical feasibility of the proposed fluorescence sensor has been demonstrated by 35 poisoning blood samples. This proposed method is proved to be quite simple and straightforward for the detection of H₂S poisoning blood. Also it may provide a basis for sulfide metabolizing study in body, and it would be meaningful to further push forensic toxicology identification and clinical laboratory research.