Antarctic snow record of southern hemisphere lead pollution

Lead concentrations from an Antarctic snow pit show the pattern of Pb reaching the Antarctic atmosphere over the last 70 years. Between 1920 and 1950, the Pb concentration shows significant variations around a mean of about 2.5 ng kg−1. Between 1950 and 1980, there is a clear increase to 6 ng kg−1, with an apparent reduction after that. A few high concentrations in the late 1970s are probably due to local contamination from aircraft using leaded gasoline (petrol). Excluding these anomalously high values, the chronological pattern in lead concentrations can be reconciled with estimates of emissions from vehicles and metal production processes in the southern hemisphere.