Impact of Automobile Exhaust on Levels of Lead in a Commercial Food From Bus Terminals

The impact of automobile exhaust on the levels of lead in commercially produced and sold white bread at bus terminals in Lagos, Nigeria were assessed. Total lead concentrations by Atomic Absorption Spectrometry were carried out. The mean concentration of lead in foods across the sites (T1-T10) ranged from 0.01 – 0.025 μgg; 0.01 – 0.03 μgg; 0.015 – 0.035 μgg and 0.005 – 0.025 μgg for the first, second, third and fourth periods of sampling respectively. The overall mean concentration of the metal varied between 0.015 – 0.026 μgg across the sampled sites. The analytical protocol was validated through the quality assurance experiment with quantitative recovery of 92.5% and C.V of 5%, which was considered applicable for routine analyses of food samples. The metal was detected in over 80% of the 160 samples that were collected and analyzed. @JASEM The ubiquity of lead and its known toxicity to man and wildlife necessitates its` continual determination in the environment. The monitoring of this metal in foods is of particular importance because it is one of the major routes by which toxic substances find their way into the human body. Primary source is mainly from natural weathering of geological materials and soils (Shea, 1996). Other sources include industrial effluents (Asamit, 1994), domestic effluents (Dean et al 1972), surface water run offs (Field and Lager, 1975) etc. However, another major contributing source of environmental lead burden is from the automobile and industrial machinery exhaust from the internal combustion engines. The use of organic lead compounds such as tetraethyl lead and tetra methyl lead as additives in petrol has been of continual concern to environmental scientists and policy makers. Studies have shown that the body lead levels of modern humans are about 500 times higher than those of pre-industrial times. It has been pointed out that Africa’s contribution to global lead pollution has increased from just 5% in the 1980s to 20% in 1996 (Nriagu, 1978). The level of lead in petrol in Nigeria was estimated as 0.7g/liter and the national consumption of petrol in the country is estimated at 20 million liters per day with about 150 people per car. It was therefore predicted that at least 15,000 kg of lead is emitted into the environment through burning (Agbo, 1997). Hence, automobile exhaust were believed to account for more than 80% of the air pollution and lead content in Nigeria’s super grade gasoline is 600 – 800 mg/liter (Osibanjo and Ajayi, 1989; Shy, 1990), which is much higher than permissible levels in some pollution conscious