[No public or meaningful name is available]

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids C10-20, reaction product with diethylenetriamine

EC Number:

940-308-0

IUPAC Name:

Fatty acids C10-20, reaction product with diethylenetriamine

Test material form:

liquid: viscous

Details on test material:

Test substance: Fatty acids, C10-20 neo, reaction product with diethyelenetriamine
Product old name MK195KSF
The test substance was received at Brixham Environmental Laboratory on 1 June 2010 and assigned the Brixham test substance number 10-0152.
The test substance (Batch Number MK195K/BM/198/067/A/001) was supplied as a hazy solid. A certificate of analysis (dated 19 July 2010, Appendix 1) stated the sample had a purity/concentration of 100%. The sample was stored in the dark, at ambient temperature, in the container in which it was
received until required for testing, when an appropriate subsample was provided for the test operator.

Specific details on test material used for the study:

Old names of the test substance: Naphthenic acids, reaction products with diethylenetriamine; MK195K.

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Study design

Test type:

other: aerobic

Water media type:

brackish water

Total exposure duration:

3 h

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Any other information on results incl. tables

The median effective concentration (EC50) is defined as the concentration, estimated from the data obtained, resulting in a 50% reduction in the respiration rate of activated sludge within the period of the test, and was estimated by the computer software, therefore, for the test substance, 3 hour EC50 >100 mg L-1.

The 20% and 80% effect concentrations (EC20 and EC80) are defined as the concentrations,estimated from the data obtained, resulting in 20 and 80% reduction respectively in therespiration rate of activated sludge within the period of the test, therefore,

3 hour EC20 >100 mg L-1.

The 10% effect concentration (EC10) is defined as the concentration, estimated from the data obtained, resulting in a 10% reduction in the respiration rate of activated sludge within the period of the test. Percentage inhibition less than or equal to 10% was within the

expected experimental variability of the test and was considered not to be an effect of the test substance.

The no observed effect concentration (NOEC) is therefore equivalent to the EC10 in this test, therefore, 3 hour NOEC = 100 mg L-1

The reference substance, 3,5-dichlorophenol, caused substantial inhibition of the respiration rate of the activated sludge. From the results obtained the 3 hour EC50 value was estimated tobe 6.9 mg L-1. This is within the expected normal range of 5 to 30

mg L-1 indicating the sludge was responding normally and confirming the viability of the sludge organisms. The respiration rates in the two control flasks were within 15% of each other.

Therefore, the mean control respiration rate was used in calculation of the percentage inhibition.

The temperatures in several flasks were below the required range of 20±2°C (minimum recorded 17.5°C). This slight deviation was considered not to have affected the validity of thestudy, as all the flasks were with 1ºC of each other.

Applicant's summary and conclusion

Executive summary:

3 hour EC50 >100 mg L-1

3 hour EC20 and EC80:

EC20 >100 mg L-1

EC80 >100 mg L-1

3 hour NOEC 100 mg L-1