Uptake of inhaled lead from motor exhaust

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Abstract
To assess the contribution of lead in motor exhaust to the total uptake of lead it is necessary to know the amount deposited in the lungs, the uptake thence to blood and other tissues, and the rate of excretion from the body. There are reports of experiments in which volunteers have inhaled aerosols of lead oxide or sesquioxide (Kehoe, 1961; Hursh et al., 1969; Booker et al., 1969; Cole and Lynam, 1972) but the physical and chemical characteristics of the particles differed from those of the exhaust aerosol. Blood lead has also been measured in persons with varying degrees of exposure to exhaust lead (Azar, Snee and Habibi, 1972; Jones, Commins and Cernik, 1972) or industrial lead (Williams, King and Walford, 1969). By attaching a radioactive label (203Pb, radioactive half-life 52 hr) to tetraethyl lead (TEL) which is then mixed with petrol and burnt in an engine, we have made a realistic tagged lead exhaust aerosol, and this has been inhaled by volunteers. The retention in the lung, removal to blood, and excretion of the lead have been followed by measuring 203Pb in the body, in blood and in excreta, using techniques of gamma-ray spectrometry.