『Abstract
This climate chamber experiment examines the effects of sewage
sludge (SS) on sulphide mine tailings from the Aitik Cu mine in
northern Sweden. The effects of SS were determined from Cu in
solution and Cu uptake and growth of plants on tailings showing
3 different degrees of weathering. Possible relationships between
Cu content in plants and Cu in solution measured in tailings (total
dissolved Cu and free Cu) were also evaluated. Red fescue (Festuca
rubra) was grown for 6 weeks in pots of the different tailings
treated with SS or NPK fertiliser. Soil solution was sampled with
Rhizon tension lysimeters and analysed for pH, dissolved organic
C (DOC), free Cu, total dissolved Cu and SO42-.
The effects of SS on Cu in solution and plants depended on the
degree of weathering. In tailings with a low degree of sulphide
oxidation, SS application resulted in increased solubility and
shoot accumulation of Cu compared with NPK-treated tailings, probably
due to DOC forming soluble complexes with Cu. Sewage sludge also
seemed to promote translocation of Cu to shoots in those tailings.
In highly weathered tailings, lower contents of total dissolved
Cu and free cu in solution and lower Cu levels in shoots were
found in SS-treated samples than in NPK-treated. In the moderately
weathered tailings, Cu concentrations in solutions were generally
similar between treatments, but lower contents of Cu were found
in shoots and roots of the fescue grown in the SS-treatment. Irrespective
of degree of weathering and treatment, both free Cu and total
dissolved Cu concentration in tailings correlated strongly with
Cu levels found in fescue shoots.』
1. Introduction
2. Material and methods
2.1. Properties of tailings and sewage sludge
2.2. Preparation and properties of A, B1 and B2 tailings
2.3. Layout of climate chamber experiment
2.4. Sampling and analyses
2.5. Statistical analysis
3. Results
3.1. Solution chemistry
3.2. Growth and Cu content of plants
4. Discussion
5. Conclusion
Acknowledgements
References