Registration Dossier

Ecotoxicological information

Toxicity to soil microorganisms

Currently viewing:

Administrative data

Endpoint:
toxicity to soil microorganisms
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
May 23, 2007 - August 28, 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study, conducted according to German guidelines for testing of plant protection products (BBA VI, 1-1, 1990). Methods and results well documented.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
BBA Part VI, 1-1
Deviations:
no
Principles of method if other than guideline:
Guideline: BBA VI, 1-1 (1990) under consideration of OECD 216 (2000) and OECD 217 (2000).
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Precal 50 S
Active ingedient / purity: calcium hydroxide / 98.2% analysed
Batch No.: 7025
Received: 30/01/2007
Expiry day: 01/2009
Appearance: white powder
Water solubility (20°C): 1650 mg/l
Storage conditions: room temperature, dry conditions

Sampling and analysis

Analytical monitoring:
yes

Test substrate

Vehicle:
no

Test organisms

Test organisms (inoculum):
soil

Study design

Total exposure duration:
96 d

Test conditions

Moisture:
Water content soil: 10.12 g/100 g soil d.w.
Water holding capacity: 39.70 g/100 g soil d.w.

Results and discussion

Effect concentrationsopen allclose all
Duration:
96 d
Dose descriptor:
NOEC
Effect conc.:
4 g/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: dehydrogenase activity
Duration:
28 d
Dose descriptor:
EC50
Effect conc.:
> 12 g/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: dehydrogenase activity
Duration:
48 d
Dose descriptor:
EC50
Effect conc.:
8.1 g/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: dehydrogenase activity
Duration:
96 d
Dose descriptor:
EC50
Effect conc.:
8.7 g/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: dehydrogenase activity

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Reference item must have an effect of at least 15% on day 28 after treatment. In the most recent study the reference item Dinoterb caused an inhibition of dehydrogenase activity of -69.4, -73.4 and -84.4% at 6.80, 16.00 and 27.00 mg per kg soil d.w.
Conclusions:
The pH of the soil increased with increasing concentrations of calcium dihydroxide. The high pH value of the soil is considered to be the toxic effect. At the highest concentration tested, the maximum pH level was 11.9 which decreased to 8.5 during the course of the study. At low test item concentration the dehydrogenase activity was stimulated.