Concentrations, speciation and decomposition of organolead compounds in rainwater

Abstract Tetraalkyllead (R 4 Pb), trialkyllead (R 3 Pb + ) and dialkyllead (R 3 Pb 2+ ) compounds were determined in rainwater collected at urban, semi-rural and rural sites using gas chromatography/atomic absorption spectroscopy (GC/AAS). At sites in England, total organolead concentrations in the range of 10–928 ng Pb l −1 were found in rainwater and ratios of organic to inorganic lead were between ng Pb l −1 R 3 Pb + species containing mixed alkyl groups were also observed. At a semi-rural site in Southeast England the deposition rate for total organic lead was 5.6 ng Pb cm −2 year −1 . No consistent seasonal variation ol alkyllead species or concentration was noted. Stability tests revealed that R 4 Pb compounds decompose quantitatively within 48 h to R 3 Pb + species in rainwater samples left in the field during sampling programmes. R 3 Pb + and R 2 Pb 2+ compounds were found to be very stable in rainwater samples left in the dark.