DETERMINATION OF ELEMENTAL COMPOSITION AND MEDIAN LETHAL DOSE OF CALABASH CHALK

Calabash chalk is a geophagic material consumed mostly for its emetic function, though other reasons are not ruled out. Toxic metals/metalloids, as well as persistent organic pollutants have been reported as constituents of the chalk. Thus, this lead to the investigation of the elemental composition of a sample from southern Nigeria and to determine its median lethal dose. Non-salted calabash chalk was analyzed for the presence of some major and trace elements using inductively coupled plasma-mass spectrometry, and their concentrations were determined by inductively coupled plasma-quadrupolar mass spectrometry. The ‘limit test’ in the ‘up and down’ procedure was used to determine the median lethal dose (LD50) with up to 5000 mg/kg body weight of calabash chalk suspension on mice. Analysis results revealed magnesium (1100±100 mg/kg±SD), aluminium (160000±15000 mg/kg±SD), potassium (5500±500 mg/kg±SD), calcium (160±14 mg/kg±SD), titanium (11000±1000 mg/kg±SD), vanadium (125±10 mg/kg±SD), chromine (130±10 mg/kg±SD), manganese (40±5 mg/kg±SD), iron (15000±1500 mg/kg±SD), cobalt (4.1±0.2 mg/kg±SD), nickel (25.5±1.3 mg/kg±SD), copper (15.5±0.7 mg/kg±SD), arsenic (11.5±0.8 mg/kg±SD), silver (0.50±0.03 mg/kg±SD), cadmium (0.76±0.04 mg/kg±SD), antimony (0.42±0.02 mg/kg±SD), barium (200±10 mg/kg±SD), thallium (0.33±0.02 mg/kg±SD), lead (57±3 mg/kg±SD) and zinc (<100mg/kg). No mortality and/or toxicity was recorded with up to 5000 mg/kg body weight of the single dose treatment of calabash chalk. In conclusion, calabash chalk contains metals/metalloids whose beneficial and adverse effect depends on their concentrations and bioavailability. While occasional use seems to pose little adverse health risks, the consequence of long-term use has not been evaluated. More research is needed to determine what adverse risks, if any, are present.