Effect of diet and environmental exposure on the levels of lead in human blood
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Date
2011-08-23
Authors
Mogwasi, Richard
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Abstract
Lead is one of the heavy metals that have been associated with a number of health problems with such effects as abdominal pains, constipation and loss of appetite, nausea, vomiting, insomnia, headache, irritability, dizziness and lead encephalopathy. The major source of lead into the environment is the emission from auto exhaust, with other contributors being cigarette smoke, burning of lead battery castings, weathering, ceramic industries and paints. Therefore there is need for continued monitoring of the levels of lead in the environment and in people to determine the level of exposure. The aim of the study was to determine the effect of environmental exposure and the protective feeding habits on the levels of lead in human blood from Nairobi City and Nyamira District. The subjects who had lived in the study areas continuously for five years were randomly selected and recruited for the study. The study used a questionnaire to assess lead exposure factors and consumption of protective foods of the recruits, while atomic absorption spectroscopy and differential pulse anodic stripping voltametry were used for determining the metal levels and UV- visible spectroscopy was used to determine the level of phosphorus in the blood. The results of the questionnaire revealed that the subjects in the different study areas were exposed to different levels of lead and they had diverse feeding habits. The subjects in Nairobi City Centre had the highest mean blood lead (BPb) level of 29.9 ± 16.91 µg/dl, while Nyamira Rural subjects had the lowest mean of 24.20 ± 7.07 µg/dl. The mean lead level of the subjects was statistically significant between Nairobi City Centre and Nyamira Rural (p< 0.05)._ The mean calcium level was highest in Nairobi Suburban with a mean of 8.83 ± 2.64 mg/dl and lowest in Nyamira Town subjects with a mean of 6.84 ± 2.65 mg/dl. The mean zinc level was highest in Nyamira Town subjects with a mean of 112.62 ± 54.34 µg/dl and lowest in Nairobi Suburban subjects with a mean of 80.64 ± 18.99 µg/dl. The mean phosphorus level was highest in Nyamira Town subjects with a mean of 3.60 ± 1.74 mg/dl while Nyamira Rural subjects had the lowest mean of 2.66 ± 0.97 mg/dl. The mean levels of calcium, zinc and phosphorus for Nairobi City Centre significantly different from those of Nyamira Town, Nairobi Suburban and Nyamira Rural (p<0.05, df = 49). There was a negative correlation of the mean levels of lead and calcium, lead and zinc and lead and phosphorus for all the study areas. The subjects of Nairobi City Centre had higher mean BPb level than those subjects from Nyamira Rural and Nyamira Town. This shows that the Cities are relatively more polluted with lead compared to the rural settings. Those subjects who fed on diets rich in calcium, zinc and phosphorus had lower mean levels of lead in their blood than the non feeders of foods rich in these nutrients. For example smokers who were non feeders of protective foods had a mean BPb level of 32.4µg/dl compared to smokers who were consumers who had a mean BPb level of 24.8µg/dl for Nairobi City Centre and the difference was statistically significant(t = 5.28,df = 7, p<0.05). Similarly those subjects who were smokers, lived near busy roads, traveled frequently or worked in lead based industries had higher BPb levels than those who did not
Description
Department of Chemistry,113p.RA 1231.L4 M6 2009
Keywords
Lead--toxicology--Kenya, Lead--physiological effect--Kenya