Hydrocarbons, C11-C13, isoalkanes, <2% aromatics

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This robust summary has a reliability rating of 1 because the study followed a standard guideline, followed GLP guidelines, and was conducted without deviations that would invalidate the study.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

other: Developed by Huls AG (Dr. Schoberl)

Deviations:

not specified

Principles of method if other than guideline:

Effects were measured by comparing oxygen consumption by the bacterium, Pseudomonas putida, over 5 hours incubation in test systems that contained varying amounts of test substance in comparison to test systems that contained no test substance (control).

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Test systems were 100 ml bottles containing medium. All test systems were stirred through the exposure period. Four innoculated bottles were established per test substance concentration. Two of these bottles at each concentration also contained HgCl2 and acted as autooxidation controls. Four innoculated bottles without test substance and with HgCl2 also acted as controls. Five innoculated bottles without test substance and HgCl2 also acted as controls. All test systems were stirred during the test.

Test organisms (species):

Pseudomonas putida

Details on inoculum:

The original culture was obtained from the Institut fur Wasser-, Boden- und lufthygiene des BGA (Berlin, Germany).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

5 h

Post exposure observation period:

None

Test temperature:

25.3

Nominal and measured concentrations:

Nominal loading levels were 100, 500, 1000, and 2000 ul/L.

Duration:

5 h

Dose descriptor:

other: EL0

Effect conc.:

2 other: ml/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

5 h

Dose descriptor:

other: EL10

Effect conc.:

> 2 other: ml/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

5 h

Dose descriptor:

other: EL50

Effect conc.:

> 2 other: ml/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

5 h

Dose descriptor:

other: EL100

Effect conc.:

> 2 other: ml/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Reported statistics and error estimates:

None were needed as no effect was measured.

Validity criteria fulfilled:

yes

Conclusions:

The test substance at the highest loading rate, 2 ml/L, did not inhibit the respiration rate of Pseudomonas putida over an exposure period of 5 hours.

Executive summary:

The test substance at the highest loading rate, 2 ml/L, did not inhibit the respiration rate of Pseudomonas putida over an exposure period of 5 hours.

Description of key information

The hydrocarbons, C11-C13, isoalkanes, <2% aromatics, estimated protozoan,Tetrahymena pyriformis, 48-hr EL₅₀ value is >1000 mg/L based on growth inhibition.

Data is also being read across from the source study that tested Isododecane based on analogue read across. 

Isododecane at the highest loading rate, 2 ml/L, did not inhibit the respiration rate of Pseudomonas putida over an exposure period of 5 hours.