Phosphoric acid C12-alkyl and C18-alkyl esters, potassium salts

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to section 13 for "Read-Across justification".

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

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

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:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to section 13 for "Read-Across justification".

Reason / purpose for cross-reference:

read-across source

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

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

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

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

from 1991-07-03 to 1991-08-13

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

different reference substance

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

different reference substance

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

up to 1 g/L, cloudy solution

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Activated sludge from the municipal STP Hildesheim

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

21 °C

Nominal and measured concentrations:

100 - 180 - 320 - 580 - 1000 mg/L nominal + control

Reference substance (positive control):

yes

Remarks:

Copper(II)sulphate-pentahydrate

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

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

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:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: 47 and 55 %

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test item on the respiration of activated sewage sludge microorganisms gave a 3-Hour EC50 >1000 mg/L nominal.

Executive summary:

A study was performed to assess the effect of the test item on the respiration of activated sewage sludge. The method followed was designed to be compatible with 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. Activated sewage sludge was exposed to an aqueous dispersion of the test item at concentrations of 100, 180, 320, 580 and 1000 mg/L nominal for a period of 3 hours at a temperature of 21 ± 1 °C.

The rate of respiration was determined after 3 hours contact and compared to data for the control a reference item, Copper(II)sulphate-pentahydrate. The effect of the test item on the respiration of activated sewage sludge gave a 3-Hour EC50 of >1000 mg/L nominal. The reference item gave a 3-Hour EC50 respiration inhibition of 47 and 55 %.

Reference 4

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

from 2012-01-10 to 2012-02-14

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:

no

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

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant D-67435 NW-Lachen-Speyerdorf
- Method of cultivation: filtrated, washed with tap water and re-suspended in tap water. The activated sludge was aerated until usage in the test and fed daily with 50 ml /L synthetic sewage feed.
- Initial biomass concentration: 1.57 g suspended solids/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

17.9 - 19.4 °C

Nominal and measured concentrations:

Nominal: 1, 10, 100, 1000 mg/L
Measured: 1.4, 10.6, 99.4, 999.8, 1000, 1002, 1008 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: narrow-neck glass bottles with flat bottoms
- Material, size, headspace, fill volume: glass, 16 mL nutrient solution with 234 mL water + test item/positiv control
- Aeration: purified air, using Pasteur pipettes, flow approx. 0.75 L/min.
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 2 before and 2 after positiv control and test item
- No. of vessels per positiv control (replicates): 1
- Nutrients provided for bacteria / Feeding: nutrient solution, 16 mL/vessel

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

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

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

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

Results with reference substance (positive control):

The reference substance showed 80 % inhibition at test concentrations of 30 and 40 mg/L. As the highest concentration did not show relevant difference to the second highest concentration, it was considered as outlier and was not used for evaluation. The EC50 of the positiv control was determined to be 6.1 mg/L. The value lies within the recommended range of 2 - 25 mg/L.

O2-Consumption, Inhibition 

Vessel No.	Content	Concentration in mg/L	O2 consumption in mg/(L*min.)	O2 consumption in mg/(L*h)	Inhibition in %	pH
1	Control	0	0.8746	52.478	0	7.4
2	Control	0	0.8736	52.414	0	7.4
3	Positive Control	5	0.4684	28.106	42.2	7.6
4	Positive Control	10	0.2597	15.582	67.9	7.5
5	Positive Control	20	0.1627	9.764	79.9	7.5
6	Positive Control	40	0.1625	9.748	79.9	7.5
7	Control	0	0.7585	45.508	0	7.4
8	Control	0	0.8003	48.019	0	7.4
9	Test Item	1000	0.6784	40.706	16.2	7.6
10	Test Item	1000	0.7687	46.122	5.1	7.5
11	Test Item	1000	0.8114	48.684	-0.2	7.5
12	Test Item	1000	0.8090	48.541	0.1	7.5
13	Test Item	1000	0.6295	37.769	22.3	7.5
14	Test Item	100	0.8140	48.838	-0.5	7.4
15	Test Item	10	0.7503	45.017	7.4	7.4
16	Test Item	1	0.7684	46.103	5.1	7.4
17	Control	0	0.7496	44.974	0	7.5
18	Control	0	0.8037	48.220	0	7.4

 

The difference between the treatment 1000 mg/L and the control can be considered as not significant. Therefore, the concentration 1000 mg/L is stated as NOEC.

Validity

- The EC50 of the positiv control was determined to be 6.1 mg/L. The value lies within the recommended range of 2 - 25 mg/L.

- The coefficient of variation of oxygen uptake rate in control replicates should not be more than 30% at the end of the test. This values was 6.7 %, which lies below the set limit.

- The blank controls oxygen uptake rate should not be less than 20 mg oxygen per one gram of activated sludge (dry weight of suspended solids) in an hour. The lowest value was determined to be 30.96 mg O2/g sludge. This value meets the required limit.

Validity criteria fulfilled:

yes

Conclusions:

The NOEC was determined to be >= 1000 mg/L after 3 hours exposure. The EC50 was determined to be >1000 mg/L, as no inhibition effects on the respiration rate of the microorganisms was observed.

Executive summary:

A study was performed to assess the effect of the test item on the respiration of activated sewage sludge. The test was performed according to OECD Guidelines for Testing of Chemicals (1984) No 209 "Activated Sludge, Respiration Inhibition Test", Method C.11 of Commission Regulation (EC) No. 440/2008. Activated sewage sludge was exposed to aqueous solutions of the test item at concentrations of 1, 10, 100 and 1000 mg/L nominal for a period of 3 hours at a temperature of 17.9 - 20.1 °C. The O2 consumption was determined after 3 hours contact and compared to data for the control. As positive control 3,5 -Dichlorophenol was tested under the same conditions. The effect of the test item on the respiration of activated sewage sludge gave a 3-Hour EC50 of >1000 mg/L nominal. No significant difference between the control group and the highest tested concentration of 1000 mg/L. Therefore, the NOEC was stated as >= 1000 mg/L. The reference item gave a 3-Hour EC50 respiration inhibition of 6.1 mg/L, which is in the required limit. The test is considered as valid.

Description of key information

Based on a weight of evidence approach using two read-across studies, the toxicity to microorganisms as EC50 was determined to be >1000 mg/L and the NOEC to be >=1000 mg/L, respectively.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

No data on the substance itself is available. The test substance is a mixture of C12 and C18 chain phosphoric acid esters. Therefore, read-across approach to the C12 and C18 phosphoric acid esters separately was applied. Two read across studies are available assessing the toxicity to microorganisms of Phosphoric acid, dodecyl ester, potassium salt (CAS 39322-78-6) and 1-Octanol, phosphate, potassium salt (CAS 68987-29-1), respectively. These studies were used in a weight of evidence-approach.

A study was performed to assess the effect of CAS 39322-78-6 on the respiration of activated sewage sludge. The method followed was designed to be compatible with 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. Activated sewage sludge was exposed to an aqueous dispersion of the test item at concentrations of 100, 180, 320, 580 and 1000 mg/L nominal for a period of 3 hours at a temperature of 21 ± 1 °C.

The rate of respiration was determined after 3 hours contact and compared to data for the control a reference item, Copper(II)sulphate-pentahydrate. The effect of the test item on the respiration of activated sewage sludge gave a 3-Hour EC50 of >1000 mg/L nominal. The reference item gave a 3-Hour EC50 respiration inhibition of 47 and 55 %.

The toxicity of the second read-across item CAS 68987-29-1 to microorganisms was determined according to OECD Guidelines for Testing of Chemicals (1984) No 209 "Activated Sludge, Respiration Inhibition Test", Method C.11 of Commission Regulation (EC) No. 440/2008. Activated sewage sludge was exposed to aqueous solutions of the test item at concentrations of 1, 10, 100 and 1000 mg/L nominal for a period of 3 hours at a temperature of 17.9 - 20.1 °C. The O2 consumption was determined after 3 hours contact and compared to data for the control. As positive control 3,5 -Dichlorophenol was tested under the same conditions. The effect of the test item on the respiration of activated sewage sludge gave a 3-Hour EC50 of >1000 mg/L nominal. No significant difference between the control group and the highest tested concentration of 1000 mg/L. Therefore, the NOEC was stated as >= 1000 mg/L. The reference item gave a 3-Hour EC50 respiration inhibition of 6.1 mg/L, which is in the required limit. The test is considered as valid.

As no effects for both components of the test substance in the toxicity to microorganisms studies were observed up to the maximum tested concentration of 1000 mg/L, it can be concluded that the test substance itself has no effect to microorganisms up until 1000 mg/L. Thus, the EC50 is determined as >1000 mg/L and the NOEC as >=100 mg/L, respectively.