Tall oil, sodium salt

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2009-04-24 to 2009-04-29

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

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L

Vehicle:

no

Test organisms (species):

activated sludge

Details on inoculum:

- Pretreatment: The activated sludge was washed three times with tap water and filtered using paper filter.

- Initial biomass concentration: The recommended amount of wet sludge for test vessels was calculated to obtain a suspended solids level of 4 g/L (±10%)

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

19.9 - 20.9 °C

Dissolved oxygen:

The preparations (control 1, 1 test loading rate of the test item, reference item in 3 test concentrations, control 2) were made up in 15 minute intervals and were aerated continuously so that a dissolved oxygen level of ≥ 6.5 mg/L was achieved during the whole test duration.

Details on test conditions:

TEST SYSTEM
- Test vessel: Control 1, 1 test loading rate of test item, reference item in 3 test concentrations, control 2.

- Type (delete if not applicable): open

- Aeration: Continuous, membrane pump

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 2

- Biomass loading rate: 100 mg/L


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



TEST CONCENTRATIONS

- Range finding study
- Test concentrations: 100 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

other: EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: 95% CL, Significant level 0.05

Results with reference substance (positive control):

- Results with reference substance valid? Yes: Deviation between respiration rates of the controls, 14.5%

- Relevant effect levels: EC50 (3 h): 12.2 mg/L, NOEC < 5.0 mg/L

Reported statistics and error estimates:

Determination of the EC50 of the reference item 3,5-dichlorophenol was accomplished using Probit-analysis (Finney-method, lognormal distribution, confidence limit 95%, significance level: 0.05).

Table2:Results of the Activated Sludge, Respiration Inhibition Test of CTO Sample 5

	c / Loading rate (mg/L)	Respiration rate (mg O2/L x h)	Inhibition (%)
Control 1	-	53.3	-
Reference	3	47.1	18.6
	10	36.4	37.1
	30	12.8	77.9
Test item	100	70.6	-22.1*
Control 2	-	62.3	-

Remark: * The negative inhibition value indicates, that the respiration rate was higher compared to the control.

Validity criteria fulfilled:

yes

Conclusions:

A Water Accommodated Fractions (WAFs) value EL50 of > 100 mg/L and a NOELR of 100 mg/L have been determined for CTO in a test conducted according to OECD 209. The result is considered reliable.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is found to be readily biodegradable and the applied test concentrations are in the range of concentrations that can be expected in the influent of a sewage treatment plant

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2009-04-24 to 2009-04-29

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

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Different laoding rates (5 - 100 mg/l)

Vehicle:

no

Test organisms (species):

activated sludge

Details on inoculum:

- Laboratory culture:
- Pretreatment: The activated sludge was washed three times with tap water and filtered using paper filter

- Initial biomass concentration: The recommended amount of wet sludge for test vessels was calculated to obtain a suspended solids level of 4 g/L (±10%)

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

19.9 - 20.9 °C

Dissolved oxygen:

The preparations (control 1, 1 test loading rate of the test item, reference item in 3 test concentrations, control 2) were made up in 15 minute intervals and were aerated continuously so that a dissolved oxygen level of ≥ 6.5 mg/L was achieved during the whole test duration.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open

- Aeration: continuous, membrane pump

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 2

- Biomass loading rate: 100 mg/l

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

other: EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: 95% CL, Significant level 0.05

Results with reference substance (positive control):

- Results with reference substance valid? Yes: Deviation between respiration rates of the controls, 14.5%

- Relevant effect levels: Yes: Deviation between respiration rates of the controls, 14.5%

Reported statistics and error estimates:

Determination of the EC50 of the reference item 3,5-dichlorophenol was accomplished using Probit-analysis (Finney-method, lognormal distribution, confidence limit 95%, significance level: 0.05).

Table2:Results of the Activated Sludge, Respiration Inhibition Test of CTO Sample 3

	c / Loading rate (mg/L)	Respiration rate (mg O2/L x h)	Inhibition (%)
Control 1	-	53.3	-
Reference	3	47.1	18.6
	10	36.4	37.1
	30	12.8	77.9
Test item	5	55.8	3.5
	10	64.9	-12.2*
	25	75.0	-29.7*
	50	69.6	-20.3*
	100	70.6	-22.1*
Control 2	-	62.3	-

Remark: * * Negative inhibition values indicate, that respiration rates were higher compared to the control. Taking into account the variation of results in the control and at the test loading rates of CTO Sample 3 the result of inhibition of 3.5 % at test loading rate of 5 mg/L is not regarded as a definite inhibition.

Validity criteria fulfilled:

yes

Conclusions:

A Water Accommodated Fractions (WAFs) value EL50 of > 100 mg/L and a NOELR of 100 mg/L have been determined for CTO in a test conducted according to OECD 209. The result is considered reliable.

Reference 4

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Remarks:

Guideline study without GLP. The test report is lacking in experimental detail but the test was conducted in accordance with a recognised guideline.

Qualifier:

according to guideline

Guideline:

other: ISO standard 11348-3:1998(E)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: Test media were prepared by dilution of a stock solution that had been prepared by 27.1x dilution of the substance.

Test organisms (species):

Vibrio fisheri

Details on inoculum:

No data

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

5 min

Hardness:

No data

Test temperature:

No data

pH:

The pH of all samples was adjusted to 7 at the start of the test in order to avoid pH effects.

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

No data

Details on test conditions:

Method

- The bacteria were exposed to samples at various concentrations for 5-15 min, after which the ability of the bacteria to generate light (bioluminescence) was measured. The toxicity was calculated from the reduction in bioluminescence. The pH of all samples was adjusted to 7 in order to avoid pH effects.

Reference substance (positive control):

no

Duration:

15 min

Dose descriptor:

EC50

Effect conc.:

0.01 other: vol. %

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: inhibition of bioluminescence

Duration:

15 min

Dose descriptor:

EC50

Effect conc.:

103 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

assuming density of sample is 1030 mg/ml

Basis for effect:

other: inhibtiion of bioluminescence

Details on results:

No data

Reported statistics and error estimates:

No data

Validity criteria fulfilled:

yes

Conclusions:

A 15-minute EC50 of 103 mg/L (0.01 vol. %) has been determined for the effects of the test substance on inhibition of bioluminescence in Vibrio fisheri

Reference 5

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Remarks:

Guideline study without GLP. The test report is lacking in experimental detail but the test was conducted in accordance with a recognised guideline.

Qualifier:

according to guideline

Guideline:

other: ISO standard 11348-3:1998(E)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: Test media were prepared by dilution of a stock solution that had been prepared by 28.5x dilution of the substance.

Test organisms (species):

Vibrio fisheri

Details on inoculum:

No data

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

5 min

Hardness:

No data

Test temperature:

No data

pH:

The pH of all samples was adjusted to 7 at the start of the test in order to avoid pH effects.

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

No data

Details on test conditions:

Method

- The bacteria were exposed to samples at various concentrations for 5-15 min, after which the ability of the bacteria to generate light (bioluminescence) was measured. The toxicity was calculated from the reduction in bioluminescence. The pH of all samples was adjusted to 7 in order to avoid pH effects.

Reference substance (positive control):

no

Duration:

15 min

Dose descriptor:

EC50

Effect conc.:

0.01 other: vol. %

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: inhibition of bioluminescence

Duration:

15 min

Dose descriptor:

EC50

Effect conc.:

103 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

assuming density of sample is 1030 mg/ml

Basis for effect:

other: inhibition of bioluminescence

Details on results:

No data

Reported statistics and error estimates:

No data

Validity criteria fulfilled:

yes

Conclusions:

A 15-minute EC50 of 100 mg/L (0.01 vol. %) has been determined for the effects of the test substance on inhibition of bioluminescence in Vibrio fisheri

Description of key information

Activated sludge respiratory inhibition (ASRI) test results have been read across from Crude Tall Oil (CTO) to TOS.

Water Accommodated Fractions (WAFs) of two CTO samples caused no acute toxic effects on bacteria in an Activated Sludge, Respiration Inhibition (ASRI) test conducted as a limit test according to OECD 209. A 3 hour EL₅₀ of > 100 mg/L and a NOELR of 100 mg/L have been determined for the test substance.

In addition, data are available for the substance itself from a study conducted in accordance with a recognised test guideline. An EC₅₀ of 103 mg/L (0.01% volume) was obtained for the effects of TOS on inhibition of bioluminescence in Vibrio fischeri. Vibrio fischeri is a bacterium found globally in marine environments. This study is selected as supporting study as the data are less relevant to waste water treatment systems.

Read-across justification:

The use of ecotoxicity data for the read-across substance Crude Tall Oil (CTO; temporary list number 931-433-1) is justified on the following basis.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH

A read across from Crude Tall Oil to TOS can be justified on the following basis.

Crude Tall Oil (CTO), list number 931-433-1, is the term applied to the processed mixture of naturally occurring compounds extracted from tree species like pine, spruce, birch and aspen. CTO is formed by the acidification of TOS, therefore, CTO and TOS are similar substances. They differ only in the water content and that CTO does not contain sodium salts of the fatty/rosin acids.

The main constituents of TOS are sodium salts of saturated and unsaturated C14-20 fatty acids (5-45% w/w), rosin acid sodium salts (10-40% w/w), water (25-45% w/w), sterols (1-10% w/w), and non-volatile lignin/cellulose fibre/oligomeric acids (3-20% w/w). In addition, the following minor constituent blocks are present: terpenes, sesquiterpenes, abietenes and labdanes, C30 branched polyakenes, 3,5 -dimethoxystilbene, rosin alcohol and aldehyde isomers and saturated/unsaturated alcohols and terpene alcohols (each <3% w/w).

The same constituents are present in CTO, with only the following differences:

-The fatty acids and rosin acids in TOS are present as their sodium salts whereas for CTO they are present as acids. In aqueous media, the sodium salts are dissociated into sodium and the parent acid. The sodium, being a ubiquitous and essential element in nature, is not expected to contribute to the toxicity properties of the substance.

-TOS contains 25-45% water compared to trace amounts in CTO; other constituent groups are therefore present at lower levels in TOS but in similar proportions to CTO.

The hypothesis for the read-across approach is that in the environment and under standard laboratory test conditions organisms would be exposed to essentially the same constituents (and in similar proportions) whether they originate from TOS or CTO and so the ecotoxicity of TOS would be substantially the same as that for CTO.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

Both CTO and TOS are UVCB substances that contain fatty acids, rosin acids, neutrals such alcohols, sterols, aldehydes etc. For UVCB substances, impurities are not considered relevant for substance identification. The fatty and rosin acids present in TOS are in the form of the sodium salt. In the environment, the sodium salts of fatty and rosin acids will dissociate and speciate in a similar way to each other. The sodium salts in TOS will ionise into sodium ions and a mixture of the acid anion/parent acid (depending on the pH) and CTO will dissociate into the same mixture of the acid anion/parent acid (again depending on the pH). Sodium is a ubiquitous, essential element in nature and will not contribute to the toxicity of the acid and as such it is considered relevant to read-across the available data for CTO to TOS.

Therefore, it can be concluded that in the environment and under standard laboratory test conditions, the organisms would be exposed to essentially the same constituents and (and in similar proportions) whether they originate from TOS or CTO and so the read-across of ecotoxicity data from CTO to TOS is justified.