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Anthropogenic heavy metals in organic forest soils

distribution, microbial risk assessment and Hg mobility

Åkerblom, Staffan (2006). Anthropogenic heavy metals in organic forest soils. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2006:67
ISBN 91-576-7116-8
[Doctoral thesis]

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The continuous heavy metal accumulation in organic topsoils in forests will pose problems for soil microbial health for many years to come. The primary objective of this thesis was to investigate heavy metal pollution in forest soils and its effects on microbial function. Heavy metal distribution and solubility as well as field- and laboratory-derived dose-response relationships were determined. These aspects were combined to evaluate the environmental status of mor layers affected by local, regional and experimental heavy metal pollution. Heavy metal distribution in humus layers was examined in field studies at two sites characterised by considerable local industrial pollution, one adjacent to a major road and the other beside a major steel plant. Around the road, Pb and Cu distribution indicated that these heavy metals were major pollutants, while Mo, Cr and Ni were highly elevated around the steel plant. There was considerable covariation among the metals studied. To improve the accuracy of heavy metal exposure assessment, different aspects of solubility were investigated. At the steelworks, deposition of alkaline dust had a significant influence on heavy metal solubility. Two further studies focused on forested areas and soil material subject to low and diffuse heavy metal pollution. One simulated heavy metal concentration gradients (Cr, Zn, Mo, Pb, Ni, Cd) in mor samples, while the other was an investigation of remote areas subject to long-range aerial Hg transport. Possible microbial risk was indicated by negative correlations between metal concentrations and soil respiration in small-scale field grids (50x50 m2 with 10 m distance between sampling points to allow for spatial independence). Negative correlations were found in plots around the major emission sources. Laboratory-derived toxicity doses for Pb and Cu supported the indication of microbial risk around the road. At the steel plant there were negative correlations between soil respiration and Mo and Ni. Heavy metal covariation obscured the effects of individual metals in the field. Examination of microbial community structure by phospholipid fatty analysis (PLFA) revealed that metals induced synchronous uniform shifts in soil microbial community structure and soil respiration in experiments. Measurement of Hg mobility with respect to DOC concentration in soil water leachates provided important data for modelling critical loads of Hg deposition on forest soils. These results show the benefits of integrated evaluation of chemical and biological indicators in soil microbial risk assessment. Heavy metal pollutants still have negative effects on forest soils at major roads and steel plants, despite recent reductions of emissions.

Authors/Creators:Åkerblom, Staffan
Title:Anthropogenic heavy metals in organic forest soils
Subtitle:distribution, microbial risk assessment and Hg mobility
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2006
Number of Pages:42
ALLI. Åkerblom, S. and Bringmark, L. Influence of proximity to roadway on metal concentrations and soil respiration in forest soils. (Submited manuscript) II. Åkerblom, S. and Bringmark, L. Effect of alkaline contamination on heavy metal distribution and availability and soil respiration in mor layers around the steel plant in Avesta, Sweden. (Manuscript) III. Åkerblom, S., Bååth, E., Bringmark, L. and Bringmark, E. Experimentally induced effects of heavy metal on mor microbial function and community structure. Biology and Fertility of Soils. (Accepted) IV. Åkerblom, S., Meili, M., Bringmark, L., Johansson, K., Berggren Kleja, D. and Bergkvist, B. Partitioning of Hg between solid and dissolved organic matter in mor layers. (Submitted manuscript)
Place of Publication:Uppsala
ISBN for printed version:91-576-7116-8
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:forest soils, humus, soil pollution, heavy metals, mercury, toxicity, solubility, dosage effects, soil microorganisms, environmental impact assessment, risk
Keywords:mor layers, heavy metal, toxicity, distribution, microbial activity, solubility, effect dose, PLFA, risk assessment, Hg, organic matter
Permanent URL:
ID Code:1198
Department:(NL, NJ) > Dept. of Environmental Assessment (until 080831)
Deposited By: Staffan Åkerblom
Deposited On:12 Sep 2006 00:00
Metadata Last Modified:02 Dec 2014 10:10

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