METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
(rapport JK 95041 2006-03-24)
Lage Bringmark and Staffan ÅkerblomDepartment of Environmental Assessment
Swedish University of Agricultural Sciences, Uppsala
in cooperation with Jernkontoret (the study was performed in 2002 and 2003)
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Objectives
•Study the load and exposure from metals in organic forest top soils (mor layer) around 2 major steel works in central Sweden
•Use total metal concentrations in soil and porewater (tension lysimeter in vitro) to study the exposure of metals to soil microbial ecosystems
•Study to what degree alkaline deposition affects metal exposure and possibly microbial function
•Study metal effects on forest soil microbial function by the use of small scale spatial patterns
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Studysites
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
Avesta•Since 17th century (Cu and Zn) •Stainless steel 1920- •Moved 1949 to present location•Smelting of scrapmetals
Production:
•Steelwork expanded production in the 1950s•Rawmaterial iron ores and coal
Oxelösund
Major metals:
•Iron(!)•molybdenum•Vanadium•(chromium and zink)
•molybdenum•chromium•nickel•(iron, copper, vanadium and cadmium)
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Field study(sampling for small scale spatial patterns)
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
A: Metals intercepted by trees are heterogeneously deposited on the forest floor
B: Samples are taken at the nodes of regular grid systems measuring 50*50m2
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Studysites
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
Avesta Oxelösund
Nyköping
1: AGA 2: Kyrkbyn 3: Grönsinka (ref) 1:Fence 2: Brannäs 3: Lid (ref)
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Podsol
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
•Mor layer: Brown-blackish, high organic content (70-95%) and low pH (3.7-4.0). Deadplant and animal material in different stages of decomposition. High metal retentioncapacity. Differentiated in upper Of-layer, lower Oh-layer.
•E-horizon: Grey colour, leached mineral soil, low organic content, pH 3.9-4.2.
•B-horizon: Reddish-brown colour, mineral soil with precipitated aluminium-ironorganiccomplexes, pH 4.3-4.7. Metal accumulation.
•C-horizon: Light-brown colour, unaffected subsoil, pH 5-6
MOR LAYER
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Metal load / exposure (1)
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
AGA (600 m) Kyrkbyn (3000 m) Grönsinka (ref)
Ratio* Mean Ratio* Mean Mean
Mo 113 277 13 31 2.4
Cr 98 733 11 83 7.4
Ni 45 560 10 129 12
Fence (1000 m) Brannäs (2000 m) Lid (ref)
Ratio* Mean Ratio* Mean Mean
Fe 23 39903(!) 13 30321(!) 1717
Mo 9.6 7.6 9.4 7.4 0.8
V 9.4 142 8.9 135 15
Oxelösund
Avesta
*Ratio to reference=mean at site
mean at reference
To
tal m
eta
l co
nce
ntr
ati
on
mg
* k
g-1
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Pore water extraction
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
1 2 3
4
1. Soil material from mor layer2. Collection vessel3. Suction vessel (-0.3 bar)4. Ceramic lysimeter probe (1 μm pore size)5. PVC tubing
5
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
pH and metal solubility
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
Avesta Oxelösund
Kd=Total metal
concentration
Dissolved metal concentration
Alkaline deposition!
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Metal load / exposure (2)
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
AGA (600 m) Kyrkbyn (3000 m) Grönsinka (ref)
Ratio* Mean (N=4) Ratio* Mean (N=4) Mean (N=4)
Mo >1000 847 10 7.9 0.8
Cr 5.5 19 5.1 18 3.5
Ni 8.7 50 5.5 32 5.7
Fence (1000 m) Brannäs (2000 m) Lid (ref)
Ratio* Mean Ratio* Mean (N=4)
Mean (N=2)
Fe
Not available
Not available
Mo 39 11.5 0.04
V Not available
Oxelösund
Avesta
*Ratio to reference=mean at site
mean at reference
Dis
solv
ed m
eta
l co
nce
ntr
ati
on
μg
* L
-1
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Microbial response to metal load (and exposure…?) 1
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
AVESTA
10.9550.598Ni
Ni10.612Cr
Cr1Mo
Mo
10.9550.598Ni
Ni10.612Cr
Cr1Mo
Mo
However….Strong covariation among metals!(Pearson correlation coefficient)
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Microbial response to metal load (and exposure…?) 2
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
10.9040.771V
V10.921Mo
Mo1Fe
Fe
10.6700.438V
V10.817Mo
Mo1Fe
Fe
However….Strong covariation among metals!(Pearson correlation coefficient)
OXELÖSUND
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Conclusion (1)
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
AVESTA:•Very high levels of metal concentrations•Only small fractions of cationic metal species (Cr and Ni) were dissolved•Mo was found in extremely high concentrations due to MoO4
- -formation in alkaline condition•Very probable toxic effects on microbial respiration
OXELÖSUND:•High levels of metal concentrations•Small fractions of metal species were dissolved•No, or minor, disturbance on microbial respiration was found
METAL LEVELS AND MICROBIAL EFFECTS IN FOREST
SOILS AT THE AVESTA AND OXELÖSUND STEEL WORKS
Conclusion (2)
Staffan Åkerblom , Lage Bringmark www.ma.slu.seMail: ([email protected]) Tel: +46 18 67 31 26
•Results on microbial toxicity were verified with experimentally derived toxic endpoints for individual metal species
•Metal distribution in the soil profile was also studied
Further reading:•Metal levels and microbial effects in forest soils at the Avesta and Oxelösund steel works. Lage Bringmark and
Staffan Åkerblom. Swedish University of Agricultural Sciences. Jernkontoret (rapport JK 95041 2006-03-24)
•Anthropogenic heavy metals in organic forest soils – Distribution, microbial risk assessment and Hg mobility. Staffan Åkerblom. PhD-thesis no. 2006:67. Faculty of Natural Resources and Agricultural Sciences. Swedish University of Agricultural Sciences. (ISSN 1652-6880; ISBN 91-576-7116-8)