Assessment of cyanide overload in cassava consuming populations of Nigeria and the cyanide content of some cassava based foods

The cyanide overload of 40 cassava (gari) processing workers, 25 frequent consumers of cassava foods and 20 cigarette smokers (all Nigerians) were assessed using a new simple kit method for determination of thiocyanate (cyanide metabolite) in urine. The mean thiocyanate measured in the urine of three groups of cassava processing workers were 9.48±2.8, 8.70±2.23, and 7.46±2.57 ppm. The mean thiocyanate measured in the urine of frequent cassava consumers and cigarette smokers were 3.57±0.6 and 13.99±13.81 ppm, respectively. The urine samples of 15% of the processing workers measured ≥10 ppm SCN (172μmol/L), while two urine samples from the smokers measured 30, and 44 ppm SCN. The cyanide contents of some cassava based foods commonly consumed among Nigerians were determined and ranged from 0.68± 0.31 to 0.88±0.21 for total cyanide and 0.14±0.03 to 0.52±01 mgCN 100g DM for free cyanide. The toxicological implications of these findings are discussed.