Soaps, stocks, vegetable-oil, acidulated

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

From May 1988 to June 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Robra K.H. (1976). Wasser/Abwasser 117:80-86

Deviations:

not specified

Principles of method if other than guideline:

Bacteriotoxic substances inhibit the bacteria's enzymatic activity, leading to a decrease in oxygen consumption. The Robra test measures oxygen consumption of Pseudomonas putida cultures exposed to various concentrations of a test substance and the EC10 or EC50 compared to a negative control is determined.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficultly soluble test substances)
- Method: The constituent was emulsified in Lauryl myristyl alcohol ethoxylate 7 EO and then added at 40,000, 50,000, 60,000, 70,000, 80,000, 90,000 and 100,000 mg/L to the test system.

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Laboratory culture: Pseudomonas putida DSM 50026
- Method of cultivation: in standard nutrient solution
- Preparation of inoculum for exposure: Pre-inoculum cultivated at 1°C for ca. 16 h on a rotary shaker. 10 mL pre-culture taken and dissolved in 200 mL nutrient solution, shaken at 26°C for ca. 16 h prior to test start.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Nominal and measured concentrations:

Nominal concentrations: 0, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000 and 100,000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 300 mL Erlenmeyer
- Aeration: with pressurized air

Reference substance (positive control):

no

Key result

Duration:

30 min

Dose descriptor:

EC10

Effect conc.:

54 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Oxygen consumption

Table 1: Toxicity of castor oil to Pseudomonas putida according to the Robra test

Castor oil concentration	% Inhibition
(mg/L)	Group 1	Group 2	Average
40,000	0	0	0
50,000	7.0	9.0	8.0
60,000	12.5	11.5	12.0
70,000	14.0	15.0	14.5
80,000	16.6	16.0	16.25
90,000	19.5	18.5	19.0
100,000	23.5	19.5	21.5

Validity criteria fulfilled:

not specified

Conclusions:

Under the test conditions, the EC10 of the constituent to Pseudomonas putida was estimated to be 54,000 mg/L.

Executive summary:

A study was conducted to evaluate the toxicity of the constituent castor oil to Pseudomonas putida according to the method described in Robra K.H. (1976) and GFW Wasser/Abwasser 117:80 -86. The microorganisms were exposed to various concentrations of the substance ranging from 40,000 to 100,000 mg/L and oxygen consumption was measured. Under the test conditions, the EC10 of castor oil to Pseudomonas putida was estimated to be 54,000 mg/L (Bessems, 1988b).

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

From June 1988 to July 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Robra K.H. (1976). Wasser/Abwasser 117:80-86

Deviations:

not specified

Principles of method if other than guideline:

Bacteriotoxic substances inhibit the bacteria's enzymatic activity, leading to a decrease in oxygen consumption. The Robra test measures oxygen consumption of Pseudomonas putida cultures exposed to various concentrations of a test substance and the EC10 or EC50 compared to a negative control is determined.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficultly soluble test substances)
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Lauryl myristyl alcohol ethoxylate 7 EO

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Laboratory culture: Pseudomonas DSM putida 50026
- Method of cultivation: in standard nutrient solution
- Preparation of inoculum for exposure: Pre-inoculum cultivated at 1°C for ca. 16 h on a rotary shaker. 10 mL pre-cuture taken and dissolved in 200 mL nutrient solution, shaken at 26°C for ca. 16 h prior to test start.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

30 min

Nominal and measured concentrations:

Nominal concentrations: 0, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000 and 100,000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 300 mL Erlenmeyer flask
- Aeration: with pressurized air

Reference substance (positive control):

no

Key result

Duration:

30 min

Dose descriptor:

EC10

Effect conc.:

67 000 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

inhibition of total respiration

Validity criteria fulfilled:

not specified

Conclusions:

Under the test conditions, the EC10 of the constituent to Pseudomonas putida was estimated to be 67,000 mg/L.

Executive summary:

A study was conducted to evaluate the toxicity of the constituent linseed oil to Pseudomonas putida according to the method described in Robra KH, 1976 and GFW Wasser/Abwasser 117:80 -86. The microorganisms were exposed to various concentrations of the substance ranging from 40,000 to 100,000 mg/L and oxygen consumption was measured. Under the test conditions, the EC10 of the constituent to Pseudomonas putida was estimated to be 67,000 mg/L.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

From 19 October 2009 to 11 November 2009

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficultly soluble test substances)
- Method: The constituent was directly dosed into each test flask and tap water was added. The mixture was stirred for about 24 h at 22°C in the dark / diffuse light.
- Eluate: Water
- Controls: 2 controls (tap water, synthetic sewage and inoculum)

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Preparation of inoculum for exposure: After centrifugation, the supernatant liquid phase was decanted. The solid material was suspended in tap water and again centrifuged (the procedure was repeated 3 times). The washed sludge was re-suspended in tap-water and sewage feed (50 mL/L) was added. The sludge was kept at room temperature under continous aeration until use overnight. The suspension was fed again on the first day.
- Initial biomass concentration: 3.8 g/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

22°C during dissolution phase
21 - 22°C during pre-incubation
18 - 20°C during evaluation period

pH:

7.4 - 8.4

Dissolved oxygen:

2.5 - 7.9 mg O2/L

Nominal and measured concentrations:

10, 32, 100, 320 and 1000 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: Flasks and Karlsruher flasks
- Type (delete if not applicable): Closed
- Material, size, headspace, fill volume: Glass, 1 L volume and 250 mL volume (Karlsruher flasks)
- Aeration: Compressed air (0.8 L/min)
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Biomass loading rate: 0.76 g/L

OTHER TEST CONDITIONS
- Adjustment of pH: No

EFFECT PARAMETERS MEASURED: Oxygen consumption, measured after 3 h of incubation time

TEST CONCENTRATIONS
- Test concentrations: 10, 32, 100, 320 and 1000 mg/L (nominal)

Reference substance (positive control):

yes

Remarks:

3,5-Dicholphenol

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

Key result

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:

EC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

- Based on measured inhibition rates, the 3 h EC10, EC30 and EC50 could not be quantified because less than 10% inhibition was observed up to the highest nonminal test concentration (1,000 mg/L).
- The maximum deviation in respiration rates was 8% at a concentration of 100 mg/L, however, no inhibition was found at a concentration of 1000 mg/L.

Results with reference substance (positive control):

- Results with reference substance valid: Yes
- Relevant effect levels: The 3 h EC50 was calculated to be 15.2 mg/L (due to mathematical reasons, no 95% CL could be determined)

For more detailed information on the results, see table 1 and figure 1 in the window 'attached background material'.

Validity criteria fulfilled:

yes

Conclusions:

Under the test conditions, no dose-related response was found in the activated sludge inhibition test with the constituent. The nominal 3 h EC10, EC20 and EC50 were determined to be >1,000 mg/L.

Executive summary:

A study was conducted to evaluate the inhibitory effect of the constituent fully hydrogenated coconut oil on activated sludge according to the guidelines OECD 209, EU method C.11 and EPA OPPTS 850.6800 in compliance with GLP. The respiration rate (oxygen consumption) of an aerobic activated sludge fed with a standard amount of synthetic sewage was measured in the presence of various concentrations of the substance after an incubation period of 3 h. Three tests, one with a reference susbstance 3,5 -Dichlorophenol and two inoculum controls were run in parallel for validation purposes. Under the test conditions, no dose-related response was found in the activated sludge inhibition test with the constituent. The nominal 3 h EC10, EC20 and EC50 were determined to be >1,000 mg/L (Feil, 2010f).

Reference 4

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

supporting study

Study period:

10 March 2010 to 28 April 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

KL2 due to RA

Justification for type of information:

Refer to section 13 for details on the read across justification. The microorganism toxicity study with the read across substance is used as a supporting 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:

EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficultly soluble test substances):
The test substance was directly dosed into test flask and tap water was added. For complete emulsification of test substance, this mixture was stirred for about 24 h at 21°C in the dark/diffuse light before adding the inoculum.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source: Municipal sewage treatment plant, Dermstadt, Germany. This STP predominantly receives domestic waste.

- Preparation of inoculum for exposure: The sludge was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and again centrifuged. The latter procedure was repeated three times. The washed sludge was resuspended in tap water and 50 mL synthetic sewage feed/L was added. The sludge was kept at room temperature under continuous aeration until use overnight. The suspension was fed on the first day before starting the experiment. The dry wt of the activated sludge was determined, and diluted to 3.8 g/L with tap water immediately before use. The pH of the activated sludge was 7.6.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

22°C during dissolution phase (24 h)
19°C during pre-incubation (3 h)
17-19°C during evaluation period

pH:

At start of exposure (0 h): 7.5-8
At end of exposure (3 h): 8.4-8.6

Dissolved oxygen:

At start of exposure (0 h): 7.9-8.2 mg O2/L
At end of exposure (3 h): 8.2-8.7

Nominal and measured concentrations:

Nominal concentration: 0, 10, 32, 100, 320, and 1000 mg/L

Details on test conditions:

- Test vessel: Glass flasks and karlsruher flasks
- Type (delete if not applicable): Closed
- Material, size, headspace, fill volume: Glass flasks of 1 L volume and Karlsruher flasks of 250 mL volume
- Aeration: Compressed air (0.8L/min)
- No. of vessels per concentration (replicates): One
- No. of vessels per control (replicates): Two (Control received tap water, synthetic sewage and inoculum without addition of the test substance)


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water
- Synthetic sewage composition:
16 g Peptone
11 g Meat extract
3 g Urea
0.7 g NaCI
0.4 g CaCl2.2H2O
0.2 g MgSO4.7H2O
2.8 g K2HPO4
filled up to 1 L with deionised water


OTHER TEST CONDITIONS: The pH and the oxygen concentrations were determined at the start and at the end of the incubation period in all treatments. The water temperature was measured in one control medium at the start and the end of the incubation period.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Well-mixed sample of each test medium was poured into Karlsruher flask after 3 h of incubation time for the measurement of the respiratory rate. The oxygen concentration was measured with an oxygen electrode and was recorded for about 10 min. During the measurement, the samples were continuously stirred. The oxygen consumption was determined from the most linear part of the respiration curve.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Range finding study: Range finding study was not conducted.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol (lot# 93297LJ and 98.9% purity) was used at a concentration of 3.2, 10, and 32 mg/L

Key result

Duration:

3 d

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 on result:

other: Less than 10% inhibition was observed at the highest tested conc.

Key result

Duration:

3 d

Dose descriptor:

NOEC

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: Less than 10% inhibition was observed at the highest tested conc., no dose related response was observed

Details on results:

- The respiration rates of the activated sludge treated with the test substance 10 to 1000 mg/L differed by less than 10% from control.

- Based on the measured inhibition rates, the 3 h EC10, EC20 and EC50 could not be quantified because less than 10% inhibition of respiration was observed up to the highest nominal test concentration of 1000 mg/L (after 3 h incubation time). No dose related response was found. No inhibition of respiration rates at a concentration of 1000 mg test substance/L was found.

- If a deviation of ≤15% between test substance-treated activated sludge and control is not considered to be an adverse effect, the NOEC of test substance will be established above 1000 mg/L (nominal).

Results with reference substance (positive control):

- Results with reference substance valid: Yes. The 3 h EC50 was 8.8 mg/L and is thus in the range of 5-30 mg/L for the used activated sludge batch.

- Other: The respiration rate of the activated sludge was moderately inhibited by 18.4% at the lowest nominal conc. of 3.2 mg/L. At the nominal conc. of 10 and 32 mg/L, the respiration rate was inhibited by 57.9 and 84.2% respectively.

Reported statistics and error estimates:

The 3 h EC50 including the 95% confidence limits of the reference substance was calculated by probit analysis.

Table 1: Influence of test substance on oxygen consumption of activated sludge

Test concentration (mg/L)	Oxygen consumption (mg O2/L min)	Inhibition %	pH		Oxygen concentration (mg O2/L)
			Start*	End*	Start*	End*
1000	0.39	-2.6	8	8.4	8	8.2
320	0.4	-5.3	7.8	8.4	7.9	8.2
100	0.38	0	7.7	8.5	8.1	8.5
32	0.38	0	7.5	8.6	8.2	8.6
10	0.38	0	7.5	8.6	8	8.7
Positive control
32	0.06	84.2	7.5	8.6	8.3	9.2
10	0.16	57.9	7.5	8.6	8.1	9
3.2	0.31	18.4	7.5	8.6	8.1	8.5
*start and end of 3 h aeration time

Control results: The respiration rates of the two controls did not differ by more than 15%. The coefficient of variation was 1.9%. Hence, the validity criterion was fulfilled.

Validity criteria fulfilled:

yes

Conclusions:

Less than 10% inhibition was noted up to the highest test substance concentration of 1,000 mg/L. Hence, under the test conditions, the nominal 3 h EC50 of the test substance was found to be >1,000 mg/L.

Executive summary:

A study was conducted to assess the effect of the read across substance, 'oils, vegetable, deodorizer distillates' on the respiration of activated sewage sludge according to OECD Guideline 209, EU method C.11 and US EPA Guideline OPPTS 850.6800. Activated sewage sludge was exposed to the read across substance at concentrations of 0, 10, 32, 100, 320, and 1,000 mg/L for a period of 3 h at a temperature of 19°C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 h contact time and compared to the data of the control and a reference substance, 3,5 -dichlorophenol. Less than 10% inhibition was noted up to the highest nominal read across substance concentration (1,000 mg/L). No dose-related response was found. Thus the 3h EC10, EC20 and EC50 of the read across substance were higher than 1,000 mg/L. The 3 h EC50 of the reference substance was 8.8 mg/L and was thus in the guideline-recommended range of 5-30 mg/L. The respiration rates of the two controls did not differ by more than 15%. Hence, the study met the validity criteria of the guideline. Under the test conditions, 3 h EC50 of the read across substance was found to be >1000 mg/L (nominal) (Feil, 2010d). Based on the results of the read across study, 3 h EC50 of the test substance, Soaps, stocks, vegetable oil, acidulated is considered to be >1000 mg/L (nominal).

Reference 5

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

supporting study

Study period:

From 10 March, 2010 to 28 April, 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

KL2 due to RA

Justification for type of information:

Refer to section 13 for details on the read across justification. The microorganism toxicity study with the read across substance is used as a supporting 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:

EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

TEST MATERIAL TREATMENT: To obtain a homogenous sample, the read-across substance was heated at 60°C in a water bath for approximately 4 h. An aliquot of the substance was filled into a bottle and was allowed to cool down to room temperature under agitation or stirring before the test was started.

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficultly soluble test substances):
The substance was directly dosed into test flask and tap water was added and the mixture was stirred for about 24 h at 21°C in the dark/diffuse light before adding the inoculum.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source: Municipal sewage treatment plant, Dermstadt, Germany. This STP predominantly receives domestic waste.
- Preparation of inoculum for exposure: The sludge was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and again centrifuged. To this mixture, 50 mL synthetic sewage feed/L was added daily, starting 2 d prior to use, and the sludge was kept at room temperature under continuous aeration until use. The dry wt of the activated sludge was determined, and diluted to 3.8 g/L with tap water immediately before use. The pH of the activated sludge was 7.5.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

21°C during dissolution phase (24 h)
19-21°C during pre-incubation (3 h)
17-19°C during evaluation period

pH:

At start of exposure (0 h): 7.4-7.5
At end of exposure (3 h): 8.3

Dissolved oxygen:

At start of exposure (0 h): 7.8-8 mg O2/L
At end of exposure (3 h): 8.1-8.5

Nominal and measured concentrations:

Nominal concentration: 0, 10, 32, 100, 320 and 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass flasks and Karlsruher flasks
- Type (delete if not applicable): Closed
- Material, size, headspace, fill volume: Glass flasks of 1 L volume and Karlsruher flasks of 250 mL volume
- Aeration: Compressed air (0.8L/min)
- No. of vessels per concentration (replicates): One
- No. of vessels per control (replicates): Two (Control received tap water, synthetic sewage and inoculum without addition of the substance)



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water
- Synthetic sewage composition:
16 g Peptone
11 g Meat extract
3 g Urea
0.7 g NaCI
0.4 g CaCl2.2H2O
0.2 g MgSO4.7H2O
2.8 g K2HPO4
filled up to 1 L with deionised water


OTHER TEST CONDITIONS: The pH and the oxygen concentrations were determined at the start and at the end of the incubation period in all treatments. The water temperature was measured in one control medium at the start and the end of the incubation period.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Well-mixed sample of each test medium was poured into Karlsruher flask after 3 h of incubation time for the measurement of the respiratory rate. The oxygen concentration was measured with an oxygen electrode and was recorded for about 10 min. The oxygen consumption was determined from the most linear part of the respiration curve.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Range finding study: Range finding study was not conducted.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol (lot# 93297LJ and 98.9% purity) was used at a concentration of 3.2, 10 and 32 mg/L.

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

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

Details on results:

- The respiration rates of the activated sludge treated with the substance at conc. between 10 to 1000 mg/L differed by less than 10% from control.
- Based on the measured inhibition rates, the 3 h EC10, EC20 and EC50 could not be quantified because up to the highest nominal test concentration of 1000 mg/L less than 10% inhibition was noted (after 3 h incubation time). No dose-related response was found. The maximum deviation in respiration rates was 7.7% at the conc. of 100 and 320 mg/L substance. Thus the 3h EC10, EC20 and EC50 are higher than 1000 mg/L under the test conditions.
- If a deviation of ≤15% between the substance-treated activated sludge and control is not considered to be an effect, the NOEC of the substance will be established above 1000 mg/L (nominal).

Results with reference substance (positive control):

- Results with reference substance valid: Yes. The 3 h EC50 was 6.5 mg/L and is thus in the guideline-recommended range of 5-30 mg/L for the activated sludge batch.
- Other: The respiration rate of the activated sludge was moderately inhibited by 33.3% at the lowest nominal conc. of 3.2 mg/L. At the nominal conc. of 10 and 32 mg/L, the respiration rate was inhibited by 61.5 and 84.6% respectively.

Reported statistics and error estimates:

The 3 h EC50 including the 95% confidence limits of the reference material was calculated by probit analysis.

Control results: The respiration rates of the two controls did not differ by more than 15%. The coefficient of variation was 1.8%. Hence, the validity criterion was fulfilled.

Table 1: Influence of the read-across substance on oxygen consumption of activated sludge

Test concentration (mg/L)	Oxygen consumption (mg O2/L min)	Inhibition %	pH		Oxygen concentration (mg O2/L)
			Start*	End*	Start*	End*
1000	0.4	-2.6	7.4	8.3	7.8	8.1
320	0.36	7.7	7.5	8.3	7.8	8.5
100	0.36	7.7	7.5	8.3	8	8.4
32	0.38	2.6	7.5	8.3	8	8.4
10	0.38	2.6	7.5	8.3	8	8.5
Positive control
32	0.06	84.6	7.5	8.3	8	9.1
10	0.15	61.5	7.5	8.3	8	9.0
3.2	0.26	33.3	7.5	8.3	7.9	8.7

*start and end of 3 h aeration time

Validity criteria fulfilled:

yes

Conclusions:

Based on the results of the read across study, 3 h EC50 of the test substance, Soaps, stocks, vegetable oil, acidulated is considered to be >1000 mg/L (nominal).

Executive summary:

Another study was conducted to assess the effect of the read across substance 'soybean oil, deodorizer distillates' on the respiration of activated sewage sludge according to OECD Guideline No. 209, EU method C.11 and US EPA Guideline OPPTS 850.6800. In this study, activated sewage sludge was exposed to the read across substance at concentrations of 0, 10, 32, 100, 320, and 1000 mg/L for a period of 3 h at a temperature of 19-21°C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 h contact time and compared to data for the control and a reference substance, 3,5-dichlorophenol. Less than 10% inhibition was noted up to the highest nominal test conc. (1000 mg/L). No dose related response was found. The maximum deviation in respiration rates was 7.7% at the conc. of 100 and 320 mg/L read across substance. Thus the 3h EC10, EC20 and EC50 are higher than 1000 mg/L. The 3 h EC50 of reference substance was 6.5 mg/L and is thus in the range of 5-30 mg/L. The respiration rates of the two controls did not differ by more than 15% (Met the validity criteria of the test). Hence, under the test conditions, 3h EC50 of read across substance was found to >1000 mg/L (nominal) in the activated sludge respiration inhibition test (Feil, 2010d). Based on the results of the read across study, 3 h EC50 of the test substance, Soaps, stocks, vegetable oil, acidulated is considered to be >1000 mg/L (nominal).

Description of key information

Based on the studies with major constituents as well as by read-across to the similar deodorizer distillates, the lower 3 h EC50 >100 mg/L (nominal) has been considered further for the hazard assessment of ‘soaps, stocks, vegetable oil, acidulated’.

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

Additional information

In absence of studies with ‘soaps, stocks, vegetable oil, acidulated’, its toxicity to micro-organisms has been evaluated on the basis of available studies with major constituents as well as by read-across to the similar deodorizer distillates.

A study was conducted to assess the effect of the read across substance, 'oils, vegetable, deodorizer distillates' on the respiration of activated sewage sludge according to OECD Guideline 209, EU method C.11 and US EPA Guideline OPPTS 850.6800. Activated sewage sludge was exposed to the read across substance at concentrations of 0, 10, 32, 100, 320, and 1,000 mg/L for a period of 3 h at a temperature of 19°C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 h contact time and compared to the data of the control and a reference substance, 3,5 -dichlorophenol. Less than 10% inhibition was noted up to the highest nominal read across substance concentration (1,000 mg/L). No dose-related response was found. Thus the 3h EC10, EC20 and EC50 of the read across substance were higher than 1,000 mg/L. The 3 h EC50 of the reference substance was 8.8 mg/L and was thus in the guideline-recommended range of 5-30 mg/L. The respiration rates of the two controls did not differ by more than 15%. Hence, the study met the validity criteria of the guideline. Under the test conditions, 3 h EC50 of the read across substance was found to be >1000 mg/L (nominal) (Feil, 2010d). Based on the results of the read across study, 3 h EC50 of the test substance, Soaps, stocks, vegetable oil, acidulated is considered to be >1000 mg/L (nominal). This is in line with the fact that the substance is readily biodegradable.

Another study was conducted to assess the effect of the read across substance 'soybean oil, deodorizer distillates' on the respiration of activated sewage sludge according to OECD Guideline No. 209, EU method C.11 and US EPA Guideline OPPTS 850.6800. In this study, activated sewage sludge was exposed to the read across substance at concentrations of 0, 10, 32, 100, 320, and 1000 mg/L for a period of 3 h at a temperature of 19-21°C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 h contact time and compared to data for the control and a reference substance, 3,5-dichlorophenol. Less than 10% inhibition was noted up to the highest nominal test conc. (1000 mg/L). No dose related response was found. The maximum deviation in respiration rates was 7.7% at the conc. of 100 and 320 mg/L read across substance. Thus the 3h EC10, EC20 and EC50 are higher than 1000 mg/L. The 3 h EC50 of reference substance was 6.5 mg/L and is thus in the range of 5-30 mg/L. The respiration rates of the two controls did not differ by more than 15% (Met the validity criteria of the test). Hence, under the test conditions, 3h EC50 of read across substance was found to >1000 mg/L (nominal) in the activated sludge respiration inhibition test (Feil, 2010d). Based on the results of the read across study, 3 h EC50 of the test substance, Soaps, stocks, vegetable oil, acidulated is considered to be >1000 mg/L (nominal).

Further, the ‘glycerides, C8-18 and C18-unsatd.’ was tested for toxicity to aquatic microorganisms in an OECD 209 Guideline study (Feil, 2010d). The 3 h EC50 was > 100 mg/L. This is in line with the fact that the substance is expected to be readily biodegradable. Similar results were obtained for ‘glycerides, C16 and C18-unsatd. and C18-unsatd. hydroxy’, ‘glycerides, C16-18 and C18-unsatd.’ and ‘glycerides, C16-22’ (Bessems, 1988 a and b).

Overall based on the above studies, ‘soaps, stocks, vegetable oil, acidulated’ is considered to have no toxicity in micro-organisms and the lower 3 h EC50 >100 mg/L (nominal) has been considered further for the hazard assessment.