A chloroform-related death: analytical and forensic aspects

Chloroform is still encountered occasionally in clinical and forensic toxicology, hence knowledge of the special problems presented in the detection and measurement of this compound in biological specimens may be required. The aim of this paper is to review the available documentation on this topic in the context of a chloroform-related death. Early one morning in February 1999 a 34-year-old female was found dead fully clothed on a path near to a neighbour's garden. Amfetamine intoxication combined with hypothermia was accepted as the cause of the death in the absence of any other identifiable cause. Further investigation 17 months later revealed a blood chloroform concentration of 31 mg/L and the cause of death was revised to chloroform poisoning. A murder trial ensued, the indictment specifying forced inhalation as the route of exposure. The liver chloroform concentration measured 38 months after collection was reported as 1064 mg/kg and opinions were offered at trial that the autopsy findings, which included a gastritis, but no evidence of injury to the inside of the mouth and oesophagus, excluded the possibility of ingestion of a toxic dose of chloroform. It was asserted that the explanation for the high liver concentration was that the liver had concentrated chloroform from blood after death against a concentration gradient. At appeal against conviction 7 years later the conviction was quashed. It was found that the liver concentration should have been reported at trial as 1 mg/kg. Moreover, chloroform found in the stomach contents (162 mg/kg) 86 months after collection was irrefutable evidence that some, if not all, of the chloroform had been ingested. Screening for volatile poisons should always be considered if a cause of death is not immediately obvious, especially in young people and in known substance abusers. If the presence of an unstable or volatile analyte is suspected then sample collection, transport, and storage must be performed with the analysis in mind. Quantitative analysis of all available specimens should proceed forthwith once the presence of an unstable analyte is established if the cause of death is in doubt or if prosecution may follow. In the case of chloroform especial precautions are needed: (i) headspace analysis should be performed at 35 degrees C to preclude the possibility of artefactual formation from trichloroacetic acid, (ii) precautions to prevent cross-contamination of biological samples in the laboratory must be taken, and (iii) interpretation of analytical results must take account of the widespread presence of chloroform in the environment on the one hand, and that the toxicity of chloroform varies greatly depending on the circumstances and intensity of exposure on the other.