Seasonal variation of the ionic alkyllead species composition of rainwater

Abstract

A comprehensive long-term survey of the concentration levels of ionic alkyllead species in rainwater at a residential location was carried out, relying on a funnel-in-bottle sampler and a well-assessed analytical procedure based on extraction, derivatization, and gas chromatography-atomic absorption spectrometry (GC-AAS). During the 1.5-year monitoring program (1986)(1987), the total dissolved ionic alkyllead content of the samples never exceeded 230 ng L-l Pb and averaged 45 ng L-l Pb. The relative concentrations of the four major species PbMe3+, PbMe22+, PbEt3+, and PbEtz2+ corresponded roughly to 4:1:2:2; the mixed methylethyllead species contributed only marginally. From the measurements, the local annual wet deposition of ionic alkyllead could be estimated at -32 pg m-2 year-l Pb. Interestingly, a seasonal variation characterized by lower concentrations in summer, which probably reflect a higher photochemical degradation rate in the atmosphere, was observed; the ethyllead species most clearly underwent this fluctuation. The results are discussed within the framework of previous studies, at this and other locations, of organolead in wet atmospheric deposition.

Northern Hemispheric Organic Lead Emissions in Fresh Greenland Snow

“…The lifetime of organolead drops in the summer and then matches that of Pb2+ aerosol, so enrichment of organolead vs Pb2+ is no longer observed. It is worth noting that a similar winter maximum for organolead compounds was observed in the only all-year study available to date (14). Note that the drop on April 15 is due to an abnormally high concentration of inorganic lead measured on this day.…”

“…Data on the composition of antiknock additives are scarce and scattered, but tetraethyllead seems to be by far the dominant additive used in Canada (II), the United States (12), and China (28). In European gasolines, the distribution of TAL species may vary drastically from one brand to another (13), but TML is generally more abundant in winter than in summer (14). A study of Belgian gasoline in winter gives a TML/TEL average ratio of 1:l (14).…”

“…Several tracers for anthropogenic emissions have been proposed (9,10) but organolead compounds as indicators of global automotive and aircraft pollution have not been considered. These compounds, however, offer some interesting features for a climatologist such as a different composition of North American (11,12) and European emissions (13)(14)(15)(16) with respect to the use of methyl-or ethyllead compounds, a year-to-year variable and known production since 1923 (17,18), and different transport mechanisms of ionic (partly alkylated) and nonpolar (fully alkylated) species (19)(20)(21)(22).…”

Biogeochemistry of trimethyllead and lead in a forested ecosystem in Germany

“…Rate constants (k), half life (t ½ ) and average life (t) in first order kinetic of trimethyllead (TML) in the Oa, Bw-C horizon of upland soils and Fen. Discussion TML concentrations in bulk precipitation reported here were in a similar range as in other rural sites in the past (Allen et al 1988, in UK), but much lower than in most of the past studies in urban areas (Van Cleuvenbergen and Adams 1992;Baena et al 2000). Thus the effect of the terminated use of OLC as fuel additives is not easily visible in our data, probably because of the near border to the Czech Republic where leaded fuel is still available.…”

Concentrations, phase partitioning and deposition of specific alkyl-lead compounds in the atmosphere

“…Several studies have shown that these changes have led to a direct impact on airborne inorganic lead levels. [8][9][10] Although tetra-alkyl species are the most abundant alkyl-lead compounds in the atmosphere, they are of low water solubility and exist essentially in the vapour phase. 5 Tetra-alkyl-lead compounds, once released into the atmosphere, have typical half-lives of 2-7 h in summer and 10-34 h in winter, 6 with tetraethyl-lead known to be less stable than tetramethyl-lead.…”