4,4'-Isopropylidenediphenol, propoxylated

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

key study

Study period:

29 December 2010 - 6 January 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The batch of LIN10001:4,4’-Isopropylidenediphenol, propoxylated tested was a white powder with lumps and a purity >95% in BPA 2 PO.

Since LIN10001:4,4’-Isopropylidenediphenol, propoxylated was hardly soluble in water test concentrations were prepared separately in Milli-RO water (tap water purified by reverse osmosis; Millipore Corp., Bedford, Mass., USA). Two 1-litre test bottles were filled with 250 ml of test substance mixtures with initial loading rates of 200 mg/l. These mixtures were stirred in closed dark brown bottles for 24½ hours. Subsequently, 16 ml synthetic sewage feed, 200 ml sludge and Milli-RO water up to 500 ml were added resulting in a loading rate of 100 mg/l (see also section 6.4). This loading rate was tested in duplicate. Optimal contact between the test substance and test organisms was ensured applying continuous aeration and stirring.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

The sludge was coarsely sieved, washed and diluted with ISO-medium. A small amount of the sludge was weighed and dried overnight at ca. 105°C to determine the amount of suspended solids (4.3 g/l of sludge, as used for the test). The pH was 7.8 on the day of testing. The batch of sludge was used one day after collection; therefore 50 ml of synthetic sewage feed was added per litre of activated sludge at the end of the collection day. The sludge was kept aerated at test temperature until use.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Post exposure observation period:

Oxygen consumption was measured and recorded for approximately 10 minutes after the 3 hours exposure period.

Test temperature:

Between 19.4 and 20.0°C

pH:

Control series: 7.9
Test substance series: 7.7-7.8

Dissolved oxygen:

Oxygen consumption:
Controls series:57-58 mg O2/l/h
Test substance series: 42-43 mg O2/l/h
The oxygen concentration at the start of measurements was at least 5.6 mg O2/l

Nominal and measured concentrations:

A loading rate of 100 mg/l, in duplicate

Details on test conditions:

TEST SYSTEM
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: All glass, approximately 300 ml oxygen bottles (measuring) and
1 litre test bottles(exposure)
- Aeration:During exposure with clean, oil-free air
- No. of vessels per concentration (replicates):2
- No. of vessels per control (replicates):2/ series
- Biomass loading rate:1.7 g/l suspended solids in final test mixture

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap-water purified by reverse osmosis (Milli-RO
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The respiration rate from each vessel, in mg O2/l/hr, was calculated from the linear part of the respiration curve, which was generally between 2.5 and 6.5 mg O2/l.

TEST CONCENTRATIONS
- Test concentrations: limit study at a loading rate of 100 mg/l

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

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

Remarks on result:

other: loading rate

Details on results:

25 and 27% inhibition of respiration rate of the sludge was recorded at a loading rate of 100 mg LIN10001:4,4’-Isopropylidenediphenol, propoxylated per litre in the duplicate measurements. Therefore, no further testing was needed. Hence, the EC50 of LIN10001:4,4’-Isopropylidenediphenol, propoxylated exceeded a loading rate of 100 mg/l.

Results with reference substance (positive control):

Results with reference substance valid: yes
The inhibitory effect of 3,5-dichlorophenol on aerobic waste water (activated sludge) bacteria increased with increased with increasing concentration , ranging from a 36 % inhibition at 5.0 mg/l to 80% at 30 mg/l. Relevant effects levels: The EC50 of 3,5-dichlorophenol was: 8.1 mg/l.

Reported statistics and error estimates:

For the reference substance the percentage inhibition was plotted against the logarithm of the concentrations and the EC50 was determined using linear regression analysis.
For LIN10001:4,4’-Isopropylidenediphenol, propoxylated no EC50 could be calculated because the test substance proved to be non-toxic (EC50 > 100 mg/l).

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this present test, LIN10001:4,4’-Isopropylidenediphenol, propoxylated was slightly toxic to waste water (activated sludge) bacteria at a loading rate of 100 mg/l (25 and 27% inhibition of respiration rate of the sludge). The 3-hour EC50 of LIN10001:4,4’-Isopropylidenediphenol, propoxylated exceeded a loading rate of 100 mg/l (based on nominal concentrations).

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

supporting study

Study period:

2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 +/- 2°C

pH:

6 - 8

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol (3,5-DCP)

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

933 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 95% CL = 430-2130 mg/L

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

The reference inhibitor 3,5-dichlorophenol (3,5-DCP)
was employed at 3, 10 and 32 mg/L, as a positive control.

Validity criteria fulfilled:

yes

Conclusions:

Possible inhibition at highest concentration with EC 20 estimated to be 933 mg/L.

Executive summary:

Possible slight inhibition at highest concentration, but significance of results not possible to determine.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 +/- 2°C

pH:

6 - 8

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol (3,5-DCP)

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

The reference inhibitor 3,5-dichlorophenol (3,5-DCP) was employed at 3, 10 and 32 mg/L, as a positive control.

Validity criteria fulfilled:

yes

Conclusions:

No biologically significant inhibitory effect on respiration rate.

Description of key information

The substance was found to be slightly toxic to microorganisms at tested concentrations.

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

Additional information

Three studies were conducted to determine the toxicity of the substance to microorganisms. All studies investigated the effects of the substance on the respiration of activated sludge. The key study followed OECD Testing Guideline 209 using BPA 2PO. The 3 hour EC₅₀ was found to be >100 mg/L. In the two supporting studies, both conducted in accordance with EU Testing Guideline C.11 the 3 hour EC₅₀ was found to be >1000 mg/l using BPA 2PO and BPA 5PO.