Alkanes, C16-47, branched and linear

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

key 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 source

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: not specified

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: not specified

Details on results:

Oxygen consumption rates and percentage inhibition values for the control, test and reference materials are given in Table 1 (see any other information on materials and results, including tables section) . The pH values of the test preparations at the start and end of the exposure period are given in Table 2 (see any other information on materials and results, including tables section), and observations made on the test preparations throughout the study are given in Table 3 (see any other information on materials and results, including tables section)
Percentage inhibition is plotted against concentration for the reference material, 3,5 dichlorophenol only (Figure 1 attached in overall remakrs and attachments section).
The following results were derived:

ECx (3 Hours) (mg/l) 95% Confidence Limits (mg/l)
EC20 >1000 -
EC50 >1000 -
EC80 >1000 -
NOEC 1000 -

It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/l.

3,5-dichlorophenol:
ECx (3 Hours) (mg/l) 95% Confidence Limits (mg/l)
EC20 2.6 -
EC50 7.9 6.1 - 10
EC80 25 -
NOEC 2.1
Variation in respiration rates of controls 1 and 2 after 3 hours contact time was ± 5%.
The validation criteria for the control respiration rates and reference material EC50 values were therefore satisfied.

Results with reference substance (positive control):

- Results with reference substance valid?
Yes.

- Relevant effect levels:
The reference material gave a 3-Hour EC50 value of 7.9 mg/l, 95% confidence limits 6.1 - 10 mg/l.

- Other:
None.

Reported statistics and error estimates:

None.

REFERENCES

Litchfield, J T and Wilcoxon, F (1949) A Simplified Method of Evaluating Dose-Effect Experints. J Pharmacol Exp Ther 96, 99-113.

Xlfit, ID Business Solutions Ltd.

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test material on the respiration of activated sewage sludge micro-organisms gave a 3-Hour EC50 of greater than 1000 mg/l. The No Observed Effect Concentration (NOEC) after 3 hours exposure was 1000 mg/l.

Executive summary:

Introduction. A study was perford to assess the effect of the test material 'Distillates (Fischer-Tropsch), heavy, C18-50 - branched, cyclic and linear’ on the respiration of activated sewage sludge. Thethod followed that described in the OECD Guidelines for Testing of Chemicals (1984) No 209 "Activated Sludge, Respiration Inhibition Test", Method C.11 of Commission Regulation (EC) No. 440/2008 and US EPA Draft Ecological Effects Test Guidelines OPPTS 850.6800.

Methods. Activated sewage sludge was exposed to an aqueous dispersion of the test material at concentrations of 10, 32, 100, 320 and 1000 mg/L for a period of 3 hours at a temperature of approximately 21°C with the addition of a synthetic sewage as a respiratory substrate.

The rate of respiration was determined after 3 hours contact tiand compared to data for the control and a reference material, 3,5-dichlorophenol.

Results. The effect of the test material on the respiration of activated sewage sludge gave a 3‑Hour EC₅₀ of greater than 1000 mg/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was1000mg/L.

It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/L.

The reference material gave a 3-Hour EC₅₀ value of 7.9 mg/L, 95% confidence limits 6.1 – 10 mg/L.

Conclusion.

The effect of the test material on the respiration of activated sewage sludge gave a 3‑Hour EC₅₀ of greater than 1000 mg/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was1000 mg/L.

It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/L.

The reference material gave a 3-Hour EC₅₀ value of 7.9 mg/L, 95% confidence limits 6.1 – 10 mg/L.

Description of key information

The 3 -hour EC₅₀ for GTL Base Oil Distillates was determined to be >1000 mg/L.
The 3 -hour NOEC for GTL Base Oil Distillates was determined to be 1000 mg/L.

This data is used for read across to Alkanes, C16 -47, branched and linear.

Additional information

The read across substance GTL Base Oil Distillates had no inhibitory effect upon activated sludge (OECD 209) in a test conducted in accordance with GLP. The 3-hr EC₅₀ was >1000 mg/L [(3h) NOEC = 1000 mg/L].