1,1'-(1-phenylethane-1,1-diyl)bis[4-(heptyloxy)benzene]

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

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

Temperature range was 22-23oC

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Test item: 4,4'-(1-phenylethane-1,1-diyl)bis(heptyloxybenzene)
Solubility and stability of the test substance in solvent/vehicle: Sparingly soluble in water
Purity: 99.56%
Purity test date: 01.02.2016
Test item storage: Room temperature
Stability under storage conditions: 21 March 2012 (expiry date)

Analytical monitoring:

not required

Vehicle:

no

Details on test solutions:

Test item mixed with Milli-RO water, synthetic medium and activated sludge to achieve nominal test loading rate of 10, 100 and 1000 mg/L

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

Hardness:

No data

Test temperature:

Nominal test temperature 20 +/- 2oC
Measured temp 22-23 oC
This deviation was not considered to adversely affect the study integrity

pH:

7.6-7.7 (start)
7.6-8.1 (end)

Dissolved oxygen:

>60% saturation at start (>5 mg/L)

Salinity:

No data

Conductivity:

No data

Nominal and measured concentrations:

Nominal loading rate 10, 100 and 1000 mg/L as test item

Reference substance (positive control):

yes

Key result

Duration:

3 h

Dose descriptor:

other: ELR50

Remarks:

Effect loading rate

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Key result

Duration:

3 h

Dose descriptor:

other: NOELR

Remarks:

No observed effect loading rate

Effect conc.:

>= 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Type of bottle	Nominal loading rate (mg/L)	pH		Respiration rate (mg O2/g/h)	% inhibition (mean value)
		Start	End
Control	0	7.6-7.7	7.6-7.8	43.4	-
Reference item	2	7.7	8.1	25.7	41
Reference item	4	7.7	8.1	22.8	48
Reference item	8	7.7	8.0	20.2	54
Reference item	16	7.7	8.0	11.3	74
Test item	10	7.7	7.6	50.3	-16
Test item	100	7.6	7.6	38.8	11
Test item	1000	7.6	7.5-7.6	46.2	-6
Abiotic control	1000	7.6	7.4	0.9	99

Validity criteria fulfilled:

yes

Conclusions:

The test item did not inhibit the respiration rate of activated sludge at a loading rate of 1000 mg/L, under the conditions of the test

Executive summary:

A reliable study to determine the activated sludge respiration inhibition for the test substance was conducted in accordance with OECD test guideline 209 and in compliance with GLP.

Under the conditions of the test, the test item was not toxic to waste water bacteria (activated sludge) after 3 hours incubation at a nominal loading rate of 1000 mg/L. The ELR50 and NOELR were both >1000 mg/L. This value is greater than the limit of solubility of the test substance.

This study is considered acceptable and satisfies the guideline requirements for a toxicity to microorganisms study.

Description of key information

A reliable study (Klimisch 1) to determine the activated sludge respiration inhibition for the test substance was conducted in accordance with OECD test guideline 209 and in compliance with GLP.

Under the conditions of the test, the test item was not toxic to waste water bacteria (activated sludge) after 3 hours incubation at a nominal loading rate of 1000 mg/L. The ELR50 and NOELR were both >1000 mg/L. The toxicity value is greater than the limit of solubility of the test substance.

The test validity criteria were met and there were no significant deviations noted to affect the integrity of the study. This study is considered acceptable and satisfies the guideline requirements for a toxicity to microorganisms study.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

EC10 or NOEC for microorganisms:

1 000 mg/L