The lead content and isotopic composition of british coals and their implications for past and present releases of lead to the UK environment

More than 60 coal samples, predominantly from the principal coalfields of England and Wales (25) and Scotland (30), were analysed for lead by AAS and for stable lead isotopes by ICPMS. While the average lead content of Scottish coal, 23.9mg kg^–1, was more than double that of coal from England and Wales, 11.0mg kg^–1, the corresponding mean ²⁰⁶Pb/²⁰⁷Pb ratios (± 1 s.d.) were nearly identical, at 1.181±0.011 and 1.184±0.006, respectively. In the light of the lead isotopic signatures of British coals and of both indigenous (²⁰⁶Pb/²⁰⁷Pb 1.17) and imported Australian (²⁰⁶Pb/²⁰⁷Pb 1.04) lead ores, an approach based on estimated lead emissions from these sources and the deconvolution of the historical lead and ²⁰⁶Pb/²⁰⁷Pb records preserved in lake sediments, peat bogs and archival herbage material indicates that coal combustion became an increasingly significant contributor to atmospheric lead deposition in the UK during the period 1830–1930, especially after the onset of Englands decline as a major location of lead mining and smelting in the late19th Century. Since 1930 and the introduction of leaded petrol, the atmospheric ²⁰⁶Pb/²⁰⁷Pb ratio in the UK has been strongly influenced by carexhaust emissions of comparatively ²⁰⁶Pbdepleted lead of predominantly Australian origin, counterbalanced to some extent by coalcombustion emissions of lead, although these have fallen dramatically since the mid1950s. Nevertheless, with the introduction and substantial uptake of unleaded petrol in the UK during the last decade, even the declining releases from coal, along with contributions from other sources, are continuing to affect the atmospheric lead content and ²⁰⁶Pb/²⁰⁷Pb ratio.