Determination of the Concentration of Total Cyanide in Waste Water of a Tobacco Company in Southwestern Nigeria

Cyanide has been listed as one of the toxic pollutants that is usually released into the environment. Cyanide is said to be released during the processing of cyanogenic plant parts which tobacco plant is one of them. This work determines the concentration of total cyanide in waste water collected in and around a tobacco company. Distillation was carried out followed by spectrophotometric analysis with pyridine-barbituric acid as the colour forming reagent and absorbance was measured at 578nm using UV-Visible spectrophotometer. The result revealed total cyanide in each sample as follows (mg/l): 0.641 ±0.004, 0.443 ±0.007, 0.319 ± 0.007, 0.184 ± 0.001 and 0.403 ± 0.004, for untreated wastewater sample, treated waste water sample from the factory, Lake water sample beside the factory where the effluent is released, upstream and downstream of a river located about 1km away from the factory, respectively. Highest value was recorded for sample collected from downstream of the river while, sample collected from the upstream have the minimum level. The levels are significantly higher than the maximum permissible levels recommended by WHO (0.2mg/l), European Union and National Agency for Food, Drugs and Administration Control (NAFDAC) (0.001mg/l) at P=0.05. Based on these findings, water from the lake and river beside the factory may not be good for drinking.