Heavy metal concentrations in peat profiles from the high Arctic

The concentration and possible sources of heavy metal input to a high Arctic mire in Kongsfjord, West Spitsbergen were examined; levels of lead, copper and zinc are highest in the surface humus closest to the carboniferous limestone cliff upon which seabirds nest. The concentrations of iron, manganese, nickel, copper, zinc and lead in two cores of peat increase markedly in the upper 5 cm of consolidated peat, with the highest concentrations found in the uppermost centimetre of peat. There has, therefore, been an increase in heavy metal loading to this High Arctic mire within the last 100 years. This cannot be attributed to the direct input of heavy metals from precipitation or coal dust from the local mines as the concentrations of the same elements in these materials are three orders of magnitude lower. It is only in the vicinity of seabird colonies that this pattern is shown and the concentrations (mu g g(-1) dry wt.) of lead, copper and zinc in faecal samples of kittiwake and glaucous gull are in the range 17-32, 35-65 and 63-260, respectively. The concentrations of these heavy metals in the faeces are close to those found in the surface layers of humus closest to the cliff. This indicates that the seabirds are acting as a vector for the movement of heavy metals between the marine and terrestrial ecosystems.