However, large doses cause odour that would alert
an individual to the presence of an unnatural substance in
drinking water and sulphide poisoning cases occur most
commonly from inhalation. Sulphide can be detected by
smell at a level of 11μg m-3, it numbs a person’s sense of
smell at a level of 140 mg m-3 and above 700 mg m-3
inhalation can very quickly be fatal (Chou, 2003).
Hydrogen sulphide in blood is rapidly oxidized by
molecular oxygen and thus reduces the oxidation power
of haemoglobin. Unoxidized hydrogen sulphide can act
upon the central nervous system and cause either
paralysis or respiratory failure (Grey, 1961).