Ombrotrophic peat bogs are unique archives for the reconstruction of fluxes of atmospheric pollutants and to analyze long term changing rates of atmospheric deposition at different time scales. For some heavy metals, like Pb and Hg, research suggests that there are natural and anthropogenic sources; while present studies also demonstrate that there is a strong climatic signal on the cycles of these two elements. For a proper assessment of present pollution levels, it is necessary to know the natural background variations and the processes that governed them in pre-anthropogenic times.This project aims to reconstruct metal atmospheric pollution in northern Spain using cores from ombrotrophic peat bogs. Other signals will be also studied: lithogenic elements, to be used as indicators of natural variations in the deposition fluxes; pollen records, to get insight into the evolution of vegetation, climate and soil use; and various isotope tracers to identify the sources (local, regional, global) of pollutants and to normalize their fluxes. 210Pb age dating will enable to make a high time-resolution reconstruction for the last century. Reconstruction at longer time scales (by radiocarbon age dating) will provide a precise knowledge of natural background variations, needed to establish the limits (upper and lower) of the intensity of present day pollution.A combination of measurements in soil, peat pore, river and rainfall waters and atmospheric measurements of Hg in the surroundings of the power plant located at As Pontes (A Coruña) will complement the study. The objective is to obtain a mass balance and a proper evaluation of the fluxes of pollutants due to coal burning. Results obtained for the last century using peat cores (normalized fluxes) will be used to elaborate a depositional model for the area, which will enable an evaluation of the impact of the power plant.
|Effective start/end date||1/12/03 → 30/11/06|