Atmospheric deposition of lead in Norway: spatial and temporal variation in isotopic composition

Moss samples collected from 22 sites all over Norway at five different times during 1977–2000 were analysed for stable lead isotope ratios. These data together with total lead concentrations and relevant literature lead isotope data from UK, western/ central Europe and eastern Europe/Russia were used to elucidate major source regions for lead deposited in different parts of the country at different times. The southernmost part of the country was most affected from western/central Europe around 1975, but the deposition declined rapidly and UK became a more significant source region in the 1980s. Recently, the influence is mostly from Eastern Europe. In the west, UK was the dominant source region during the whole period. In the middle and northern regions, the deposition was low but also decreasing regularly, and the main source region was probably the North Atlantic. In the far north–east, influence from Russia and eastern Europe was dominant during the whole period.