Tetraalkyl lead compounds

Organic Lead. Following a single exposure to vapors of tetraalkyl lead compounds (approximately 1 mg/m3 breathed through a mouthpiece, 10-40 breaths of approximately 1 L volume) in four male subjects, 37% and 51% of inhaled tetraethyl and tetramethyl lead, respectively, were initially found in the respiratory tract, but a considerable percentage of these volatile compounds was lost through exhalation (Heard et al. 1979). Approximately 60-80% of the deposited tetraalkyl lead was absorbed by the lungs. 

Organic Lead. Urinary lead levels were elevated for 4 days in a man accidentally exposed to an unknown quantity of tetramethyl lead (Gething 1975). Exhalation of the tetraalkyl lead compounds following inhalation exposure is a major route of elimination in humans. At 48 hours postexposure, 40% and 20% of the initially inhaled tetramethyl and tetraethyl lead doses, respectively, were exhaled with low urinary excretion (Heard et al. 1979). 

Biomarkers of exposure for inorganic and organic forms of lead are usually the measurement of total lead levels in tissues or fluids. Total lead measurements of biological media includes all metabolites and endogenous lead sources as well as any original lead-containing exposure agent. Tetraalkyl lead compounds may also be measured in the breath. 

In water, tetraalkyl lead compounds are subject to photolysis and volatilization with the more volatile compounds being lost by evaporation. Degradation proceeds from trialkyl lead to dialkyl lead to inorganic lead. Tetraethyl lead is susceptible to photolytic decomposition in water. Triethyl and trimethyl lead are more water-soluble and therefore more persistent in the aquatic environment than tetraethyl or tetramethyl lead. The degradation of trialkyl lead compounds yields small amounts of dialkyl lead compounds. Removal of tetraalkyl lead compounds from seawater occurs at rates that provide half-lives measurable in days (DeJonghe and Adams 1986). 

Chau YK, Wong PTS, Bengert GA, et al. 1979. Determination of tetraalkyl- lead compounds in water, sediments, and fish samples. Anal Chem 51 186-188. 

Sirota, G.R. and J.F. Uthe. 1977. Determination of tetraalkyl lead compounds in biological materials. Anal. Chem. 49 823-825. 

Speciation of lead in air and atmospheric particulates is still a topic of great environmental relevance. Sodium tetrahydroborate may be used to hydrogenate inorganic lead ions and alkyl-lead species.60 As in the study by Balls outlined above, cryogenic trapping may again be used to trap temporarily the plumbane and alkyl- and tetraalkyl-lead compounds, which are then released sequentially by heating for detection by flame AAS. 

O3) have not been attained. In contrast, MTBE was incorporated in European gasoline as an octane enhancer to replace banned tetraalkyl lead compounds and increasing restrictions on aromatics content. 

The significance of organolead residues in aquatic life is unknown, and merits additional research. In Ontario, Canada, about 16% of all fish sampled contained tetraalkyl lead compounds, alAough none were recorded in... 

Harrison, R. M. and Perry, R. (1977), The Analysis of Tetraalkyl Lead Compounds and their Significance as Urban Air Pollutants,Environ., 11, 847-52. 

Chan, L., The Determination of Tetraalkyl Lead Compounds in Petrol Using Combined Gas Chromatography—Atomic Absorption Spectrometry, Forensic Sci. Intern. 18 [1981] 57/62. 

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