Record of industrial pollution in polish ombrotrophic peat bogs

Abstract

Peat contains mostly diamagnetic organic matter, which is a good collector of all kinds of atmospheric dusts and industrial pollution. Ombrotrophic peat bogs are built up above the ground water table, so deposition and accumulation of magnetic particles are not influenced by ground water and the deposited particles remain largely “in situ”. During this study, 6 Polish ombrotrophic peat bogs from different locations have been investigated. Peat cores of about 30–50 cm in depth were taken from every bog. The specific low-frequency magnetic susceptibility was measured along the peat profile in fresh, not dried sample. In most profiles the susceptibility below 10 cm was slightly negative, which is characteristic for clean organic material. Above a depth 8–10 cm the susceptibility starts to increase. Independently of the profile location, the increase is observed in all bogs and according to isotopic (C-14) dating it is connected with the post war industrialisation (1945–1955). The maximum of the magnetic deposition noticed as maximum susceptibility enhancement is observed in a depth of about 5 cm below the surface. In the south-western part of Poland the peat profiles show the maximum susceptibility above 350 ×10⁻⁸m³kg⁻¹. The susceptibility decreases in profiles from the central part of Poland to 30–60. In the northern and southeastern part of the country the maximum observed susceptibility is about 10 ×10⁻⁸m³kg⁻¹. Hysteresis parameters pointed at anthropogenic ferromagnetic minerals as a carrier of magnetic signal.