Biphenyl-4,4'-diol

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted to current OECD test guideline and in accordance with the German principles of GLP. A GLP certificate is present within the report

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

NA

Vehicle:

no

Details on test solutions:

Test solutions were prepared by direct addition of a weighed quantity of test substance to 200 ml of autoclaved tap water and stirred overnight.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

The sludge was washed twice with autoclaved tap water and concentrated to a dry sludge concentration of 3.0 g/L +/_ 10% and used within 24 hours after sampling. The date of receipt was was 21 November 2011 and the dry sludge concentration was 2.93 g/L. The inoculum originated from a
municiple sewage treatment plant of D-31137 Hildesheim, Germany

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Post exposure observation period:

NA

Hardness:

NA

Test temperature:

20.4 degrees C

pH:

Activated sludge: 7.84
Synthetic waste water: 7.74

Dissolved oxygen:

NA

Salinity:

NA

Nominal and measured concentrations:

Nominal concentrations: 10, 32, 100, 320 and 1000 mg/L

Details on test conditions:

The concentrations used for the definitive test were based on the results of a range finding test conducted at 10, 100 and 1000 mg/L.
The definitive test was conducted with triplicate control and test vessels. Test concentrations of 58, 100 and 180 mg/L were also included for the reference substance.

The test vessels were 1000 mL Erlenmeyer flasks containing a test medium volume of 500 mL that was composed of 250 mL inoculum, 16 mL synthetic waste water, 234 mL autoclaved tap water and a direct weighing of test substance.

Following the 3 hour incubation, the oxygen concentration of each control, reference item and test item replicate was determined using a oximeter immediatley after transferring the solution to the measuring cell. The oxygen depletion was recorded for at least 3 minutes on a flat bed recorder. During the measurement of oxygen depletion the temperature was determined once in the cell.

Reference substance (positive control):

yes

Remarks:

Copper (II) sulphate pentahydrate (CAS No. 7758-99-8)

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

<= 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

10.96 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: <10 - 21.33

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

Key result

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

The EC20 was determined to be 10.96 mg/L and the EC50 was considered to be >1000 mg/L to the activated sludge of a municipal sewage treatment plant. The inhibition of respiration rate was 39% at 320 mg/L and 36% at 1000 mg/L

Results with reference substance (positive control):

The EC50 inhibition of respiration for the reference substance was in the expected range and calculated to be 105.4 mg/L (the recommended range of validity is 53 - 155 mg/L)

Validity criteria fulfilled:

yes

Conclusions:

The EC50 was > 1000 mg/L to activated sludge of a municipal sewage treatment plant.

Executive summary:

A 3-hour GLP compliant static respiration inhibition test with activated sludge was conducted according to OECD Guideline No. 209 was carried out with the test item 4,4-Biphenol, with the experimental phase on 22 November 2011. The activated sludge was obtained from the municipal treatment plant of D-31137 Hildesheim, Germany.

The EC₅₀ was determined to be >1000 mg/L

Description of key information

EC20 determined to be 10.96 mg/L and EC50 was greater than the maximum tested concentration (>1000 mg/L)

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

Additional information

A 3-hour GLP compliant static respiration inhibition test with activated sludge was conducted according to OECD Guideline No. 209 was carried out with the test item 4,4-Biphenol (batch number: 071111370), with the experimental phase on 22 November 2011. The activated sludge was obtained from the municipal treatment plant of D-31137 Hildesheim, Germany.

 

The EC50 was determined to be >1000 mg/L

Suitable conclusions can be made based on the results of the study