Fly ash content and distribution in lake sediments around a large power station: inferences from magnetic susceptibility analysis

The bulk magnetic susceptibility of sediments from artificial and natural lakes around a large coal-fired power station in NE Spain has been measured. Higher magnetic susceptibility values are found in lake sediments located SE of the power station. This distribution of susceptibility values is compatible with environmental and meterological studies of emissions from the power station, which indicate a dominant SE plume direction. Mineralogical studies, by means of X-ray diffraction and scanning electron microscopy, show that the highest susceptibility values found in the sediments are caused by magnetic iron spinels in the fly ash that is transferred to the environment by the power station particulate emissions. After the quantitative mineralogical studies of fly ash, two different methods of fly ash content determination in the sediments have been devised, showing very similar results. The low background magnetic susceptibility of the sediments in the study area and the high susceptibility resulting from the input of magnetic fly ash particles allows both delimitation of the polluted area around the power station, and quantification of the fly ash input into the natural sediments.     

Indicators to identify the agricultural pressures on environmental functions and their use in the development of agri-environmental measures

The effects of agricultural activities on the environment can be presented by suitable pressure indicators. These pressure indicators can also be used as control variables to achieve a desired environmental state. Therefore, pressure indicators can play a decisive role in the elaboration of agri-environmental measures. This paper deals with the use of pressure indicators to assess the sustainability of agricultural land use on the one hand, and their contribution to the development of agri-environmental measures on the other hand. After the illustration of the general political background on the CAP evolution and the information needed for monitoring, control and ex-post assessment, the methodological approach of the AEMBAC project to provide this information is presented. Experiences in applying pressure indicators in assessing the agri-environmental measures are discussed and their applicability for the identification of environmental impacts, management and monitoring is evaluated.