Ashes (residues), cenospheres

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil microorganisms

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions, Basic data given

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

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

AMENDMENT OF SOIL
- Type of organic substrate: LUFA - standard soil 2.2

Test organisms (inoculum):

other: Arthrobacter globiformis

Total exposure duration:

3 h

Test temperature:

30 °C

Moisture:

0.6 g of ash-soil-mixture was moisturised with 0.6 mL of water

Details on test conditions:

TEST SYSTEM
- Testing facility: ECT Oekotoxikologie GmbH, Flörsheim am Main, Germany
- Test container: 24-well plates
- Amount of soil: 0.6 g of ash-soil-mixture
- No. of replicates per concentration: 4
- No. of replicates per control: number not reported (controll was siliceous sand)


DETAILS OF PREINCUBATION OF SOIL (if any):
- prior to testing soil (in 24-well plates) was heated twice to inhibit soil inherent dehydrogenase activity


TEST PERFORMANCE
- after the soil (in 24-well plates) was cooled down the inoculum was added and incubated for 2 hours on a shaker
- subsequent 0.8 mL of resazurin were added and fluorescence was measured over a period of 1 hour
- Photoperiod: continuously darkness


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- activity of dehydrogenase was assessed by photometric measurements of fluorescence

Nominal and measured concentrations:

see table 1 in "any other information on materials and methods incl. tables"

Reference substance (positive control):

yes

Remarks:

BAC and zinc

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

> 1 000 g/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: dehydrogenase activity

Under the conditions of this study no EC50 could be determined. Based on raw data (without statistical analysis) the test substance seems to have no significant effect on the dehydrogenase activity of Arthrobacter globiformis.

Table 2: Inhibition of dehydrogenase activity of Arthrobacter globiformis

Dilution	1/128	1/64	1/32	1/16	1/8	1/4	1/2	100% ash
inhibition of dehydrogenase activity [%]	-	-	-0.6	-2.6	2.1	-1.9	-2.3	-1.6

Conclusions:

Under the conditions of this study no EC50 could be determined. Based on raw data (without statistical analysis) the test substance seems to have no significant effect on the dehydrogenase activity of Arthrobacter globiformis.

Description of key information

No harmful effect could be observed, he test substance has no significant effect on the dehydrogenase activity of Arthrobacter globiformis.

Additional information

On behalf of the VGB PowerTech e. V. the toxicity of ashes to plants was assessed by Roembke (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). The tested fly ash (FA1) was structural related to ash (residues), cenospheres and as cenospheres are a component of fly ash, these results can be used as read across. 

During an exposure period of 3h, Arthrobacter globiformis was exposed to different concentrations of fly ash. Under the conditions of this study no EC50 could be determined. The test substance has no significant effect on the dehydrogenase activity of Arthrobacter globiformis.