Tetradecafluorohexane

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

November 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Deviations:

not applicable

Remarks:

QSAR model adapted specifically to test guideline: OECD 209

Principles of method if other than guideline:

The respiration inhibition of activated sludge was determined using a validated QSAR model for the Mechanism of Action (MechoA) in question (MechoA 1.1, i.e. non-polar narcosis) (3).The QSAR model is based on validated data for a training set of 12 chemicals derived from 30-180 minute EC50 for which the concentrations of the test item had been determined by chemical analyses over the test period. Further valid data were available but the values were all above the water solubility of the substance and were therefore not included as part of the regression.
On the other hand, these data could be used to determine the point at which the regression no longer holds true and results from experimental studies on this MOA are expected to be greater than the solubility limit (i.e. test substance concentrations up to 100 mg/L will result in no effect on activated sludge respiration).

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Tetradecafluorohexane

EC Number:

206-585-0

EC Name:

Tetradecafluorohexane

Cas Number:

355-42-0

Molecular formula:

C6F14

IUPAC Name:

tetradecafluorohexane

Test material form:

liquid

Study design

Test type:

static

Water media type:

not specified

Total exposure duration:

180 min

Remarks on exposure duration:

The model provides an in silico prediction for the 30 to 180 miutes EC50 value that can effectively be used in place of an experimentally derived 30 to 180 miutes EC50 value.²

Results and discussion

Effect concentrations

Key result

Duration:

180 min

Dose descriptor:

EC50

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

not determinable

Remarks:

> solublity limit

Any other information on results incl. tables

The result below is the toxicity value anticipated during a 30 to 180 minute study on respiration inhibition of activatedsludge. The 30-180 min EC₅₀is calculated as follows:

 

Parameter	Toxicity value (mg test item.L^-1)	95% confidence limits (mg test item.L^-1)
30-180min EC50	> solublity limit	not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

No toxicity is anticipated in the limit of solubility further to a 30-180 minute study on activated sludge based on measured concentrations.

Executive summary:

Introduction.

A Quantitative Structure-Activity Relationship (QSAR) model was used to calculate the inhibition of respiration to activated sludge of the test item 1,1,1,2,2,3,3,4,4,5,5,6,6,6-TETRADECAFLUOROHEXANE. This QSAR model has been validated to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004) and predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following Guideline for Testing of Chemicals No. 209, "Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation)" (1), referenced as Method C.11 of Commission Regulation No.

440/2008 (2). The criterion predicted was the 30 to 180 minutes EC50 (Median Effective Concentration for specific respiration rate), a statistically derived concentration which is expected to cause 50% inhibition of intrinsic rate of respiration of the test system within a period of 30 to 180 minutes as an effect on the organic carbon oxidation

process. The results from this study do not include the supplementary test results that may be required to determine the effect on nitrification. It should be noted that a specific test duration time could not be determined for this model as 30 and 180 minute data were available but not in sufficient quantity to separate them into two separate models.

Methods.

The respiration inhibition of activated sludge was determined using a validated QSAR model for the Mechanism of Action (MechoA) in question (MechoA 1.1, i.e. non-polar narcosis) (3).The QSAR model is based on validated data for a training set of 12 chemicals derived from 30-180 minute EC50 for which the concentrations of the

test item had been determined by chemical analyses over the test period. Further valid data were available but the values were all above the water solubility of the substance and were therefore not included as part of the regression. On the other hand, these data could be used to determine the point at which the regression no longer holds true and

results from experimental studies on this MOA are expected to be greater than the solubility limit (i.e. test substance concentrations up to 100 mg/L will result in no effect on activated sludge respiration).

Results.

The result below is the toxicity value anticipated further to a 30-180 minute study on activated sludge based on measured concentrations:

Parameter	Toxicity value (mg test item.L^-1)	95% confidence limits (mg test item.L^-1)
30-180min EC50	> solublity limit	not applicable