Mohammed Allan

Reconstructing historical atmospheric mercury deposition in Western Europe using: Misten peat bog cores, Belgium

Four sediment cores were collected in 2008 from the Misten ombrotrophic peat bog in the Northern part of the Hautes Fagnes Plateau in Belgium. Total mercury (Hg) concentrations were analyzed to investigate the intra-site variability in atmospheric Hg deposition over the past 1,500 years. Mercury concentrations in the four cores ranged from 16 to 1,100 μg kg(-1), with the maxima between 840 and 1,100 μg kg(-1). A chronological framework was established using radiometric (210)Pb and (14)C dating of two cores (M1 and M4). Pollen horizons from these two cores were correlated with data from two additional cores, providing a consistent dating framework between all the sites. There was good agreement between atmospheric Hg accumulation rates in the four cores over time based on precise age dating and pollen chronosequences. The average Hg accumulation rate before the influence of human activities (from 500 to 1,300 AD) was 1.8 ± 1 μg m(-2)y(-1) (2SD). Maximum Hg accumulation rates ranged from 90 to 200 μg m(-2)y(-1) between 1930 and 1980 AD. During the European-North American Industrial Revolution, the mean Hg accumulation rate exceeded the pre-Industrial values by a factor of 63. Based on comparisons with historical records of anthropogenic activities in Europe and Belgium, the predominant regional anthropogenic sources of Hg during and after the Industrial Revolution were coal burning and smelter Hg emissions. Mercury accumulation rates and chronologies in the Misten cores were consistent with those reported for other European peat records.

VARIATIONS OF TREE RING WIDTH AND CHEMICAL COMPOSITION OF WOOD OF PINE GROWING IN THE AREA NEARBY CHEMICAL FACTORIES

Abstract This study reports the variation of tree-ring widths and annual variation of concentration of metals (Na, Mg, Fe, Ni, Cu, Zn, Pb) in pine growing nearby chemical factories. The conifers (Pinus silvestris L.) investigated in this study covered the time span from 1920s to 2010 AD. Tree-ring widths were measured, dated and rechecked using the COFECHA. Radial trace-element profiles were determined by Laser Ablation Inductively Coupled Plasma Mass Spectrometry. The combined usage of tree ring width and chemical composition of wood provides historic records of anthropogenic impact on the environment and allows identifying the behavior adaptation of trees to the pollution. Data of pine tree cores collected from the sites nearby chemical factories show increasing levels of pollution linked to the increasing of industrial activities in Poland and subsequent dust fallout around the site. This study evidences that tree rings can be used as archives of past environmental contamination.