Herbal Medicines?: A Case Study

1
Hydrogen Sulphide and Cocaine
A Lethal Cocktail
1Analytical Unit, St Georges, University of
London, UK ² Health Safety Laboratory,
Derbyshire, UK 3Forensic Science Service Ltd,
Lambeth, London, UK 4Dept of Histopathology,
Guys St Thomas NHS Foundation Trust, London,
UK
Exposure via Inhlation Exposure via Inhlation Exposure via Inhlation
Concentration Concentration
Concentration Concentration
2 2
4 4
8 8
5 to 10 5 to 10
4 to 21 4 to 21
20 20
gt100 gt100
gt402 gt402
gt502 gt502
Exposure via Inhlation Exposure via Inhlation Exposure via Inhlation
Concentration Concentration
Concentration Concentration
2 2
4 4
8 8
5 to 10 5 to 10
4 to 21 4 to 21
20 20
gt100 gt100
gt402 gt402
gt502 gt502
V.Hayward¹,
K.Jones², J. Button3, S.Lucas4 M.Puchnarewicz1and
D.W.Holt1
Introduction
Hydrogen sulphide (H2S) is a colourless gas which
is produced and used in the chemical
manufacturing industry it can be also generated
naturally by the putrefaction of organic
substances.1 In low concentrations it is
characterised by the odour of rotten eggs, but as
the concentration of the gas increases, the
olfactory nerve is overwhelmed and the gas can no
longer be sensed.
Table 1. Human Health Effects of
Hydrogen Sulphide at Various Concentrations
2 Hydrogen sulphide is unstable and rapidly
metabolised in the body, one of the major
metabolites is thiosulphate formed by the
oxidation of sulphide.3 Post-mortem reports
after industrial accidents have shown blood
thiosulphate concentrations of 25-120µmol/L and
18.47-20.48µmol/L.34 In addition to
accidental deaths, hydrogen sulphide has recently
become a tool for suicide. The first trend of
using hydrogen sulphide for this means was
reported in Japan in 2008 5 and there have been
several cases highlighted in the United Kingdom
(UK) in 2010. Instructions enabling individuals
to create the deadly gas are readily available
online. A simple method involves the mixing of a
household chemical, such as drain cleaner, with a
sulphur containing product, such as pesticide, in
a confined space.
Routine screening of blood and urine samples was
carried out at the Forensic Toxicology Service
aliquots of these samples were sent to the Health
and Safety laboratory for thiosulphate analysis.
Methodology
Thiosulphate calibrators were prepared in blood
and urine over a range of 0 to 500µmol/L. 200µL
of calibrator/sample and 100µL of 10µM
tribromobenzene were derivatised using
pentafluorobenzyl bromide and extracted into 2mL
25mM iodine ethyl acetate solution and 1µL
injected onto the GCMS system. A BP-5 equivalent
GC column (30m x 0.32mm id, 1um film) was used
with helium as the carrier gas. The oven was
held at 100ºC for 2 minutes then ramped at 10 ºC
/min. The ions monitored were m/z 426 for the
thiosulphate and m/z 314 for tribromobenzene.

Results
Figure 3. Benzoylecgonine Chromatogram relating
to the case
A blood benzoylecgonine concentration greater
than 15mg/L was detected. This is the highest
concentration ever detected by the Forensic
Toxicology Service and falls well within fatal
ranges (table 2).
Figure 1. A Recent hydrogen sulphide suicide
pact (20 Sep 10)
Figure 4. Chromatograms of thiosulphate
calibrator and samples.
In a case received by the Forensic Toxicology
Service, hydrogen sulphide was seen in
combination with high levels of cocaine. Cocaine
is the second most abused illicit drug in the UK,
behind cannabis, with an estimated 0.8 million
adults reporting use of the drug in the last
year. 6 The most common clinical symptoms of
cocaine toxicity include central nervous system
stimulation, ventricular arrhythmias, respiratory
dysfunction and ultimately respiratory
paralysis. Cocaine has an average half-life of 1
hour and is rapidly metabolised to
benzoylecgonine, which appears in the plasma
within 15 to 30 minutes of cocaine
administration. 7
The Health and Safety Laboratory reported a blood
thiosulphate concentration of 64µmol/L, which
falls within fatal ranges. The urine
concentration, of 2.7mmol/mol creatinine, was low
but this would be expected if death had occurred
soon after exposure. Urine concentrations in
survivors have been reported between
12-50mmol/mol.
Table 2. Fatality ranges in blood, taken from
Baselt and supplied by the Health Safety
Laboratory
Figure 2. The Chemical Structure of
Benzoylecgonine
Conclusion
Case study
This case is an example of death caused by
combined toxicity, both the blood concentration
of benzoylecgonine and thiosulphate were within
fatal ranges. HM Coroner ruled that the deceased
had taken his own life by creating the deadly gas
and taking a cocaine overdose. Extensive
toxicological screening also revealed the
presence of ethanol, cannabis and olanzapine, but
these were at low concentrations unlikely to
have contributed to the death.
On 20th June 2010, Police were contacted by a
friend concerned about the welfare of a 30 year
old man who had not responded to telephone calls
or email. Upon gaining entry to the property, a
deceased male was discovered in the bathroom. In
the bath were two tubs containing unknown
substances and a bottle of an unknown liquid.
Specialist units were called in due to the strong
smell of ammonia and the presence of the unknown
substances. They established that a lethal gas
had been created by mixing a sulphur based
product with battery acid. White powder,
suspected to be cocaine, was also recovered from
the house along with a signed suicide note.
Neighbours reported that 5 days previously there
had been a smell of bad eggs, which they had
put down to faulty drains. At post-mortem a
green discolouration to the brain was noted,
which is consistent with hydrogen sulphide
exposure. The pathologist reported that the
heart did not exhibit the usual pathological
features of chronic cocaine use, suggesting a
one-off acute toxicity.
References
1 R.G.Hendrickson et al. Co-worker Fatalities
From Hydrogen Sulfide. Amer J Indust Med. 2004
45346-350.2 Adapted from M.Cush, Hydrogen
Sulphide, Toxicological Overview. Health
Protection Agency. 2009 1. 3 S.Kage et al. The
Usefulness of Thiosulfate as an indicator of
hydrogen sulfide poisoning 3 Cases. Int J Legal
Med 1997. 110220-222 4 Kage et al. Fatal and
Nonfatal Posioning by Hydrogen Sulfide at an
Industrial Waste Site. J Forensic Sci. 2002.
47(3)625-5 5 K.C Wei et al. Suicide in Asia.
Int Rev Psychiatry. 2008. Oct20(5)434-40. 6
2009/10 British Crime Survey, available online
http//rds.homeoffice.gov.uk/rds/pdfs10/hosb1310.p
df 7 B.Levine ed. Principles of Forensic
Toxicology, 2nd Edition. 2006 AACC Press,
Washington