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Assessment of the spatial distributions of total- and methyl-mercury and their relationship to sediment geochemistry from a whole-lake perspective

Rydberg, Johan and Rosén, Peter and Lambertsson, Lars and De Vleeschouwer, François and Tomasdotter, Sophia and Bindler, Richard Assessment of the spatial distributions of total- and methyl-mercury and their relationship to sediment geochemistry from a whole-lake perspective. (2012) Journal of Geophysical Research, 117 (G4). ISSN 0148-0227

(Document in English)

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Official URL: http://dx.doi.org/10.1029/2012JG001992


The aim of this study was to determine the spatial variability for total- and methylmercury in surface sediments (0–2 cm) across a single whole-lake basin, and to relate this variability to the sediment’s geochemical composition. 83 surface sediment samples from Stor-Strömsjön – a lake with multiple sub-basins located in northern Sweden – were analyzed for geochemical composition as well as total-mercury (total-Hg) and methylmercury (methyl-Hg; 35 samples) concentrations. Our results indicate that variations in fine-grained mineral matter (36%) and organic matter (34%) explain an equal amount of the total-Hg variation, but that their relative importance varies between different parts of the lake. Total-Hg concentrations were similar in locations controlled by organic matter or fine-grained mineral matter (average 109 ng g␣1); however, total-Hg inventories (mass per unit area) were significantly higher in the latter (35 and 53 mg m␣2, respectively). Methyl-Hg concentrations are largely (55% of variance) controlled by water depth and sulfur concentration, which supports the importance of within lake methylation reported from other studies. Both for concentrations and inventories the spatial distribution for methyl-Hg in surface sediments is patchy, and interestingly the highest methyl-Hg inventory (1.4 mg m␣2) was found in a shallow location with coarse-grained minerogenic sediment (very low organic matter). A large spatial variability, even within a single lake, is something that needs to be recognized, e.g., when studying processes affecting mercury cycling, mercury loadings and when using lake sediments to reconstruct historic mercury deposition.

Item Type:Article
Additional Information:Thanks to American Geophysical Union editor. The original PDF of the article can be found at Journal of Geophysical Research website : http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)2169-8961
HAL Id:hal-00987057
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Other partners > Umea University (SWEDEN)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Laboratory name:
Deposited On:05 May 2014 11:56

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