Determination of thiocyanate among smokers and non-smokers using urine as a biological indicator and other contributing factors of cyanide exposure
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Date
2011-08-23
Authors
Nyachoti, Syprose Kemunto
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Abstract
The low levels of thiocyanate (SCN) normally present in body fluids increase with chronic exposure to cyanide. Cyanide (CN-) is a fast-acting, potentially deadly chemical which prevents or inhibits cellular respiration and inactivation of cytochrome oxidase killing the cell. Humans are exposed to cyanide from dietary, industrial, environmental and other sources. Tobacco smoking is an important source of cyanide exposure. After absorption, cyanides are readily distributed in the body through the blood and are converted to thiocyanate by sulphur transferase enzyme. Thiocyanates are removed from the body through urine. Thus, the determination of urine SCN is a necessary study in establishing the extent of cyanide overload. This study was therefore set to evaluate the concentration of thiocyanate in urine of smokers (n = 128) and non-smokers (n = 123) aged between 20-70 yrs as a biomarker of cyanide exposure. The sampling covered Kahawa Wendani, Kahawa Sukari, Githurai, Ruiru, Kiwanja and Kenyatta University in Nairobi and Thika, Kenya. Information on factors that influence the accumulation of cyanide was assessed using a questionnaire. The UV-visible spectrometer was used to determine the concentration of the thiocyanate using the picrate paper method, developed by Bradbury et al. The mean thiocyanate measured in the urine of smokers was 3.89 ± 0.17 mg/L and that of non-smokers was 1.99 ± 0.12 mg/L. The mean SCN levels in smokers were significantly higher than those of non-smokers (P<0.05; df = 230). Factors that were found to have significant influence were diet particularly cassava and sorghum which gave values of 4.16±0.33 mg/L and 3.75±0.27 mg/L respectively. Utilization of cassava in Kenya is limited to a few places, however, cassava and its products have been reported to be highly used in western (Busia) and coastal regions of the country. The duration and number of cigarettes per day were found to have a statistically significant influence. Fifteen samples purposively sampled were analysed using Lundquist method mainly for comparison purposes. For the samples analysed by these methods, a regression line gave very good agreement (r2 = 0.9942). This information can be used to sensitize the public on the effects of cigarette smoke. The results of this study can also be used by the government to formulate policies and strategies to reduce cyanide exposure thereby addressing some of the health issues affecting people in Kenya
Description
Department of Chemistry, 83p. The RA 1242 .H9N9 2009
Keywords
Cyanides --Toxicology, Thiocyanates, Smoking --Health aspects --Kenya, Tobacco use --Kenya, Tobacco use --Kenya, Smoking --Health aspects --Kenya, Cyanides --Toxicology, Thiocyanates