A comparative study of sediment trace metal levels in upland lakes in the southern and northern Carpathians of Romania

• Main Author: Akinyemi, O. F.
• Published: University of Salford 2013
• Subjects: 551.3; Built and Human Environment
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594919

The Carpathian Mountains in Romania hold around 150-200 glacial lakes and traverse a region where there are considerable environmental concerns. Despite a long tradition of palaeoecological study in the region, to date relatively little has been published on the alteration of their sediment characteristics due to recent human-induced environmental impacts. This research project has investigated the physical characteristics, the mineral magnetic properties and the trace metal levels of sediment cores from ten selected lakes in the southern and northern Carpathians of Romania in order to evaluate the possibility of using these lakes’ sediment as records of recent human impacts and, in particular, trace metal deposition. Laboratory analysis has included sediment bulk density measurements, loss-on-ignition and laser diffraction based particle size determination, environmental magnetism and geochemical (ICP-OES) analysis. A single core from one of the south lakes (Lacul Capra) was radiometrically dated. There were distinct variations in catchment and lake area, the ratio of catchment area to lake size and in lake depth between both regions. The physical characteristics of the lake sediments demonstrated similar trends in their down core profiles in both regions, although the lakes from the south demonstrated a larger particle size range than those in the north. The environmental magnetism of the sediment cores demonstrated common characteristics in surface or near surface peaks magnetic concentration, but there were variations in the magnitude of the concentrations between both regions. The surface increase in concentrations indicated the influence of the atmospheric deposition of particulate deposition associated with fossil fuel combustion and vehicle emissions, but it may also be influenced by microbiological activities within the lakes’ sediment. The geochemical analysis (EFs and down-core profiles) showed that the same trends in metal concentration were repeated across the lakes in both regions, but the south lakes displayed higher peak in Pb and Zn concentrations, than were found in the north lakes. The research project has demonstrated the likely influence of atmospheric particulate deposition on the sediments of the lakes from both regions and it has demonstrated spatial and temporal variations in trace metal levels in the lake sediments. It has thereby provided a preliminary database and an overview of palaeolimnological information in two regions of the Romanian Carpathians. Thus, it provides an addition to the records of recent pollution in Romania and a gateway to further investigations in the area of recent palaeoenvironmental change in this region.