LEAD ACCUMULATION IN PLANKTON BLOOMS FROM ULLSWATER, THE ENGLISH LAKE DISTRICT

Concentrations of lead in plankton samples from Ullswater were compared with concentrations in samples from Bassenthwaite Lake and Mockerkin Tarn. Melosira and Asterionella blooms from Ullswater contained up to 772μg Pb g-1 organic dry weight, whilst samples from the other lakes contained 29-167 μg Pb g-1. The Ullswater phytoplankton represented a lead concentration factor in excess of 100,000 and possible mechanisms for this are suggested. It was estimated that these algal blooms contributed 1-2 mg Pb m-2 to the sediment. Data from the zooplankton indicated that lead from phytoplankton may have been transferred and accumulated into the zooplankton food chain. © 1979.