Pathological effects of lead.

Abstract

The emission sources and pathological effects of lead are discussed. The emission from the internal combustion engine totals about 200,000 tons/yr and is the largest single factor in the redistribution of Pb from natural sources to biological systems. All other sources of emission of Pb in the United States produce less than 4000 tons or less than 2% of the Pb emitted from gasoline exhausts. The form of Pb in the environment is inorganic Pb. There is no evidence that alkyl Pb or methyl Pb is synthesized in nature or is produced in a stable form as a product of any industrial process. Organic Pb compounds in gasoline are converted to halides by halogens added to fuels as scavengers to facilitate removal of Pb from auto engines. Approximately 50% of the Pb emitted from automobile exhausts is deposited within 30 m of the roadway. The pathological effects of Pb are most prominent in three organ systems: the nervous system, hematopoietic system, and kidneys. Excessive exposure to Pb results in clinical toxicity. There is uncertainty regarding the potential harmful effects of low levels of Pb that do not produce overt toxicity. The retention of lead, cellular response to lead, neuropathology, hematologicalmore » and renal effects of lead, and factors influencing susceptibility are described.« less