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Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Endpoint:
toxicity to microorganisms
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: DIN-method (draft), GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)
Principles of method if other than guideline:
other: Pseudomonas-growth inhibition test: Umweltbundesamt "Bewertung wassergefaehrdender Stoffe" (1979): Bestimmung der biologischen
Wirkung von Wasserinhaltsstoffen auf Bakterien im Zellvermehrungshemmtest; DEV DIN 38 412 (L8), draft.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
99.9 % purity
Reported to be a clear colorless liquid received from the sponsor.
Stored at room temperature, protected from light

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
Stock solutions of MAA were prepared by dissolving 1.6722 g in 1505 g test medium and neutralized to pH =7 by addition of NaOH solution. From
this stock solution, appropriate dilutions were prepared in test medium to yield final concentrations 0, 1.0, 10, 100, 180, 320, 560, and 1000 mg/L.

Test organisms

Test organisms (species):
Pseudomonas putida
Details on inoculum:
A culture of the gram negative bacteria (Stamm Berlin 33/2) was supplied by Deutsche Sammlung von Mikro-organismen, Braunschweig, Germany. A pre-culture was prepared for the growth inhibition test by innoculating the appropriate medium with a suspension prepared from a stock culture with an optical density of 0.194 and incubating at 21+/- 1C for 15-16 hours after which the optical density was 1.243. The pre-culture was centrifuged
and the bacteria re-suspended in fresh test medium.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
16.5 h

Test conditions

Test temperature:
approx. 21 degree C
pH:
7.0
Nominal and measured concentrations:
Nominal = 0, 1.0, 10, 100, 180, 320, 560, and 1000 mg/L.
Details on test conditions:
There were three flasks per concentration of neutralized test substance, two flasks of the unneutralized test substance and two control series
containing (neutralized and unneutralized) test substance but no bacteria to allow for correction of th OD of the test substance.
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
17 h
Dose descriptor:
EC50
Effect conc.:
270 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks on result:
other: 95% CI =216-338
Duration:
17 h
Dose descriptor:
EC10
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Details on results:
Results with non-neutralized test-solution (pH = 3.4-4.7):
EC10 = 12 mg/l
EC50 = approx. 32 mg/l
The acidic substance is considerably more toxic than the neutralized one.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In a valid guideline study, the EC50 for MAA to Pseudomonas putida was 270 mg/L after 17 hours; the EC10 was 100 mg/L.
Executive summary:

In a valid guideline study, the EC50 for MAA to Pseudomonas putida was 270 mg/L after 17 hours; the EC10 was 100 mg/L.