Ashes (residues), plant

Toxicity to soil microorganisms

Administrative data

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: DIN 38412-L48 (2002); German standard methods for the examination of water, waste water and sludge - Bio-assays (group L) - Part 48: Toxicity test with Arthrobacter globiformis for contaminated solids (L 48)

GLP compliance:

no

Remarks:

Test were performed to fulfill the requirements of 2000/532/EG and Dir 91/689/EEC, GLP was not required for that purpose

Test material

Test material information

1

Reference substance name:

Ashes (residues)

EC Number:

268-627-4

EC Name:

Ashes (residues)

Cas Number:

68131-74-8

Molecular formula:

Not available / UVCB substance

IUPAC Name:

FBC Ash (residues of coal combustion in fluidized bed combustion boilers)

Test material form:

solid: particulate/powder

Details on test material:

Wirbelschichtasche (WSA)

Specific details on test material used for the study:

mg/kg (in solid FBC ash samples)
Arsenic (As) 10.8
Cadmium, Cd 0.93
Cobalt (Co) 8.17
Chromium (Cr) 47.4
Copper (Cu) 140
Molybdenum (Mo) 16.7
Nickel (Ni) 27.3
Lead (Pb) 65.5
Antimony (Sb) 9.34
Selenium (Se) 5.76
Vanadium (V) 104
Zinc (Zn) 415

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (inoculum):

other: Arthrobacter globiformis (freeze-dried)

Study design

Total exposure duration:

3 h

Remarks:

Inkubation 2 h

Test conditions

Test temperature:

30°C

Details on test conditions:

permanent darkness;
TEST SYSTEM
- Testing facility:
- Test container (type, material, size): microtiter plates
- Amount of soil: Dilution levels from LUFA standard soil 2.2 and ashes; per replicate 0.6 g plus 0.6 ml water
- No. of replicates per concentration: 4
- No. of replicates per control: not specified


SOIL INCUBATION
- prior to testing soil (in 24-well plates) was heated twice to inhibit soil inherent dehydrogenase activity

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
LUFA standard soil 2.2



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
After cooling the soil, the inoculum was added and then incubate on a shaker. Then addition of 0.8 ml resazurin per replicate and photometric recording of the fluorescence over a total of 1 h


TEST CONCENTATION
dilution levels: 1/32; 1/16; 1/8; 1/4; 1/2; 1

Reference substance (positive control):

yes

Remarks:

Validity Criteria: Inhibition of 30 - 80% in limit tests with two reference chemicals (BAC, zinc) and the fluorescence of the control increases by a factor of at least 5 (measurement time 0 - 60 minutes)

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

32.3 - 66.7 g/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Inhibition of dehydrogenase activity

Details on results:

see table 1

Any other information on results incl. tables

Tab. 1: Inhibition of dehydrogenase activity in the bacterial contact test with A. globiformis; Effective threshold: 20%

Dilution level	1/32 3,1 %	1/16 6,3 %	1/8 12,5 %	1/4 25 %	1/2 50 %	1 100 %
Inhibition of dehydrogenase activity (%)	-10,5	99,3	99,1	99,4	99,2	99,2

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

Under the conditions of this study EC50 for dehydrogenase activity was not calculated but must be between 32.3 - 66.7 g/kg soil dw (exposure duration: 3h).

Executive summary:

The toxicity of Ashes from fluidized bed combustion coal fired power stations with and without co-combustion of secondary fuels (FBC Ash) to soil microorganisms was assessed by Römbke (2008) according to the DIN 38412-L48 (2002); German standard methods for the examination of water, waste water and sludge - Bio-assays (group L) - Part 48: Toxicity test with Arthrobacter globiformis for contaminated solids (L 48). During an exposure period of 3h the Arthrobacter globiformis was exposed to different concentrations of FBC ash (dilution levels: 1/32; 1/16; 1/8; 1/4; 1/2 and 1).

Under the conditions of this study EC50 for dehydrogenase activity was not calculated but must be between 32.3 - 66.7 g/kg soil dw (exposure duration: 3h).