Potassium isooctadecanoate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

The presented study was conducted with isooctadecanoic acid. The read across source substance is considered a structural analogue with regard to environmental fate and effects on aquatic organisms taking into account the physico-chemical properties (surface active properties, logKow, water solubility) and the chemical structure of the test item (potassium soap of isooctadecanoic acid) and therefore the results of the source substance are considered relevant for risk assessment. See read across document for further details.

Qualifier:

according to guideline

Guideline:

DIN 38414 (German standard methods for the examination of water, waste water and sludge – Sludge and sediments (group S) – Determination of the organically bound halogens amenable to extraction (S 17))

Deviations:

not specified

GLP compliance:

yes

Specific details on test material used for the study:

Name of test material (as cited in study report): Isostearic acid, Prisorine 3505
Physical state: liquid
Analytical purity: approx. 100%
Lot/batch No.: 80011
Storage condition of test material: at ambient temperature in the dark

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Pseudomonas putida

Details on inoculum:

Laboratory culture: Stock culture obtained from RIVM, Bilthoven, The Netherlands
Method of cultivation: kept on nutrient used for stock and preliminary cultures in agar plant tubes. New cultures were started at intervals of 1 week. The inoculated stock cultures were incubated at 25 °C.
Preparation of inoculum for exposure: Using aseptic techniques, small amounts of bacteria from a 7-day old stock culture of Pseudomonas putida were inoculated in fluid nutrient medium in Erlenmeyer flasks. The preliminary cultures were incubated at 25°C for 18 +/- 2 hours.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

18 h

Test temperature:

25°C

pH:

pH of test solution was adjusted to 7.0 +/- 0.2 using NaOH

Nominal and measured concentrations:

Nominal concentrations: 0.001, 0.002, 0.005, 0.009, 0.019, 0.038, 0.075, 0.150, 0.300, 0.600, 1.2, 2.4, 4.8 mg/L
No actual concentrations were measured.

Details on test conditions:

Test system / test vessel

Material, size, headspace, fill volume: Erlenmeyer flasks, filled with 100 mL
No. of vessels per concentration (replicates): 3
No. of vessels per control (replicates): 1

Test medium / water parameters

Source/preparation of dilution water: Milli-Q water

Effect parameters measures: Cell multiplication

Reference substance (positive control):

yes

Remarks:

Methanol

Key result

Duration:

18 h

Dose descriptor:

NOEC

Effect conc.:

> 4.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

growth inhibition

Key result

Duration:

18 h

Dose descriptor:

EC50

Effect conc.:

> 4.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

growth inhibition

Details on results:

None of the concentrations in the dilution series of Prisorine 3505 showed colouration or turbidity: therefore no correction for the extinction values of the dilution series was made. For the performance of the acute bacteria toxicity test of Prisorine 3505, the solubility of Prisorine 3505 in water must be available. The solubility of Prisorine 3505 in water was determined in analogy to the known solubilities in water of three different fatty acids. The fatty acids each vary in the length of the carbon-hydrogen chain: C8, Caprylic acid, solubility in water at 20°C is 680 mg/l; C14, Myristic acid, solubility in water at 20°C is 20 mg/l; C18, Stearic acid, solubility in water at 20°C is 3.0 mg/l. According to the chain length and the corresponding solubility value, the solubility of Prisorine 3505 (C18 Isostearic acid) was adjusted to 3 mg/l. Also an excess of test substance (6.0 mg/l) was dissolved in Milli-Q water and exposed to the bacteria as discribed in 3.5 (concentration 238‘). The real solubility of this oversaturated test substance solution is therefore unknown. The extra test flasks with the oversaturated test substance solution were prepared as follows: in addition to the test procedure for the preparation of the dilution series, four Erlenmeyer flasks (coded I 23“, II 23", III 233*, t 253‘) were filled with 80 ml oversaturated test substance solution, 5 ml stock solution I, 5 ml stock solution II and 10 ml bacterial suspension . The total experiment was carried out with the following series of dilutions: 2^0, 2^1, 2^2, 2^3, 2^4, 2^5, 2^6, 2^7, 2^8, 2^9, 2^10 and 2^11. All the extinction values measured lie close to the horizontal reference line, so no toxicity threshold (TT) value of Prisorine 3505 for Pseudomonas putida can be determined (Table 1). The TT value of methanol determined for Pseudomonas putida was 6036 mg/l (Table 1). With respect to the known literature TT value of methanol (6600 mg/l) and considering the existing differences in definitions for the TT value in the literature concerned, it can he concluded that the test conditions were optimal and the results obtained are valid.

Stock solution I
20.000 9 D(+}-glucose (for biochemical and microbiological purposes):
4.240 g sodium nitrate, NaNOs. A.R.;
2.400 g dipotassium hydrogen phosphate, KzflPca:
1.200 g potassium dihydrogen phosphate, KHzP04, A.R.;
30 m1 trace elements solution.
Glucose and nutrient salts were dissolved each separately in 500 ml Milli-Q water, sterilized in a steam sterilizer and united when cooled.

Stock solution II
0.200 g ferrous sulphate, Fe504.7H20, A.R.;
4.000 9 magnesium sulphate, HgSO4.7H20, A.R.
Both nutrients were dissolved in Milli-Q water and sterilized in a
steam sterilizer.

Results with reference substance (positive control):

The TT value for methanol determined for Pseudomonas putida in this test was with 6030 mg/L comparable to the ones in literature (6600 mg/L) and thus the test was considered to be valid.

No effect up to the limit of the water solubility of the test substance was observed under conditions tested.

 

Table 1: Extinction values of the inoculated dilution series I, II, III, the control flasks B and the reference dilution series R

Extinction 436 nm

Methanol			Prisorine 3505
B	mg/l	R	mg/l	I	II	III	Mean I, II, III
.425	4937.500	.397	0.001	.394	.409	.403	.402
.430	9875.000	.348	0.002	.391	.412	.415	.406
.412	19750.000	.271	0.005	.420	.400	.414	.411
.430	39500.000	.144	0.009	.392	.420	.392	.401
.412	79000.000	.097	0.019	.392	.395	.342	.376
.425			0.038	.395	.400	.392	.396
.450			0.075	.386	.385	.385	.385
.444			0.150	.398	.380	.378	.385
.412			0.300	.405	.385	.380	.390
.450			0.600	.383	.382	.375	.380
			1.200	.385	.379	.393	.386
			2.400	.440	.425	.441	.435
Mean			4.800	.442	.462	.456	.453
.429

Methanol reference      

90%-line .386

TT value 6035.842 mg/l

 

Prisorine 3505

TT value none

Validity criteria fulfilled:

yes

Conclusions:

All the extinction values measured for Prisorine 3505 lie close to the horizontal reference line, so no toxicity threshold (TT) value of Prisorine 3505 for Pseudomonas putida can be determined (Table 1). The TT value of methanol determined for Pseudomonas putida was 6036 mg/l . With respect to the known literature TT value of methanol (6600 mg/l) and considering the existing differences in definitions for the TT value in the literature concerned, it can he concluded that the test conditions were optimal and the results obtained are valid. The 18 h NOEC of the test substance to microorganisms was determined to be >4.8 mg/L (nominal).

Executive summary:

A study was conducted to determine the toxicity of the test substance to microorganisms according to DIN 38414. Pseudomonas putida bacteria were exposed to the test substance at nominal concentrations of 0.001, 0.002, 0.005, 0.009, 0.019, 0.038, 0.075, 0.150, 0.300, 0.600, 1.2, 2.4 and 4.8 mg/L for 18 h. In addition, one controls, and ten different concentrations of the reference substance methanol were tested. The extinction values at 436 nm were measured. The inhibitory effect of the test substance was expressed as a percentage of the mean extinction values of the controls. Up to and including the concentration of nominal 4.8 mg/L, the test substance had no inhibitory effect on Pseudomonas putida bacteria after the incubation period of 18 h. The extinction values of the positive control were in the range of known literature values for methanol compared to the controls confirming the suitability of the used bacteria. Under the study conditions, the 18 h NOEC of the test substance to microorganisms was determined to be >4.8 mg/L (nominal).

Reference 2

Endpoint:

toxicity to microorganisms, other

Type of information:

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

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

The presented study was conducted with isooctadecanoic acid. The read across source substance is considered a structural analogue with regard to environmental fate and effects on aquatic organisms taking into account the physico-chemical properties (surface active properties, logKow, water solubility) and the chemical structure of the test item (potassium soap of isooctadecanoic acid) and therefore the results of the source substance are considered relevant for risk assessment. See read across document for further details.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

DIN 38414 (German standard methods for the examination of water, waste water and sludge – Sludge and sediments (group S) – Determination of the organically bound halogens amenable to extraction (S 17))

Deviations:

not specified

GLP compliance:

yes

Specific details on test material used for the study:

Name of test material (as cited in study report): Isostearic acid, Prisorine 3505
Physical state: liquid
Analytical purity: approx. 100%
Lot/batch No.: 80011
Storage condition of test material: at ambient temperature in the dark

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Pseudomonas putida

Details on inoculum:

Laboratory culture: Stock culture obtained from RIVM, Bilthoven, The Netherlands
Method of cultivation: kept on nutrient used for stock and preliminary cultures in agar plant tubes. New cultures were started at intervals of 1 week. The inoculated stock cultures were incubated at 25 °C.
Preparation of inoculum for exposure: Using aseptic techniques, small amounts of bacteria from a 7-day old stock culture of Pseudomonas putida were inoculated in fluid nutrient medium in Erlenmeyer flasks. The preliminary cultures were incubated at 25°C for 18 +/- 2 hours.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

18 h

Test temperature:

25°C

pH:

pH of test solution was adjusted to 7.0 +/- 0.2 using NaOH

Nominal and measured concentrations:

Nominal concentrations: 0.001, 0.002, 0.005, 0.009, 0.019, 0.038, 0.075, 0.150, 0.300, 0.600, 1.2, 2.4, 4.8 mg/L
No actual concentrations were measured.

Details on test conditions:

Test system / test vessel

Material, size, headspace, fill volume: Erlenmeyer flasks, filled with 100 mL
No. of vessels per concentration (replicates): 3
No. of vessels per control (replicates): 1

Test medium / water parameters

Source/preparation of dilution water: Milli-Q water

Effect parameters measures: Cell multiplication

Reference substance (positive control):

yes

Remarks:

Methanol

Key result

Duration:

18 h

Dose descriptor:

NOEC

Effect conc.:

> 4.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

growth inhibition

Key result

Duration:

18 h

Dose descriptor:

EC50

Effect conc.:

> 4.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

growth inhibition

Details on results:

None of the concentrations in the dilution series of Prisorine 3505 showed colouration or turbidity: therefore no correction for the extinction values of the dilution series was made. For the performance of the acute bacteria toxicity test of Prisorine 3505, the solubility of Prisorine 3505 in water must be available. The solubility of Prisorine 3505 in water was determined in analogy to the known solubilities in water of three different fatty acids. The fatty acids each vary in the length of the carbon-hydrogen chain: C8, Caprylic acid, solubility in water at 20°C is 680 mg/l; C14, Myristic acid, solubility in water at 20°C is 20 mg/l; C18, Stearic acid, solubility in water at 20°C is 3.0 mg/l. According to the chain length and the corresponding solubility value, the solubility of Prisorine 3505 (C18 Isostearic acid) was adjusted to 3 mg/l. Also an excess of test substance (6.0 mg/l) was dissolved in Milli-Q water and exposed to the bacteria as discribed in 3.5 (concentration 238‘). The real solubility of this oversaturated test substance solution is therefore unknown. The extra test flasks with the oversaturated test substance solution were prepared as follows: in addition to the test procedure for the preparation of the dilution series, four Erlenmeyer flasks (coded I 23“, II 23", III 233*, t 253‘) were filled with 80 ml oversaturated test substance solution, 5 ml stock solution I, 5 ml stock solution II and 10 ml bacterial suspension . The total experiment was carried out with the following series of dilutions: 2^0, 2^1, 2^2, 2^3, 2^4, 2^5, 2^6, 2^7, 2^8, 2^9, 2^10 and 2^11. All the extinction values measured lie close to the horizontal reference line, so no toxicity threshold (TT) value of Prisorine 3505 for Pseudomonas putida can be determined (Table 1). The TT value of methanol determined for Pseudomonas putida was 6036 mg/l (Table 1). With respect to the known literature TT value of methanol (6600 mg/l) and considering the existing differences in definitions for the TT value in the literature concerned, it can he concluded that the test conditions were optimal and the results obtained are valid.

Stock solution I
20.000 9 D(+}-glucose (for biochemical and microbiological purposes):
4.240 g sodium nitrate, NaNOs. A.R.;
2.400 g dipotassium hydrogen phosphate, KzflPca:
1.200 g potassium dihydrogen phosphate, KHzP04, A.R.;
30 m1 trace elements solution.
Glucose and nutrient salts were dissolved each separately in 500 ml Milli-Q water, sterilized in a steam sterilizer and united when cooled.

Stock solution II
0.200 g ferrous sulphate, Fe504.7H20, A.R.;
4.000 9 magnesium sulphate, HgSO4.7H20, A.R.
Both nutrients were dissolved in Milli-Q water and sterilized in a
steam sterilizer.

Results with reference substance (positive control):

The TT value for methanol determined for Pseudomonas putida in this test was with 6030 mg/L comparable to the ones in literature (6600 mg/L) and thus the test was considered to be valid.

No effect up to the limit of the water solubility of the test substance was observed under conditions tested.

 

Table 1: Extinction values of the inoculated dilution series I, II, III, the control flasks B and the reference dilution series R

Extinction 436 nm

Methanol			Prisorine 3505
B	mg/l	R	mg/l	I	II	III	Mean I, II, III
.425	4937.500	.397	0.001	.394	.409	.403	.402
.430	9875.000	.348	0.002	.391	.412	.415	.406
.412	19750.000	.271	0.005	.420	.400	.414	.411
.430	39500.000	.144	0.009	.392	.420	.392	.401
.412	79000.000	.097	0.019	.392	.395	.342	.376
.425			0.038	.395	.400	.392	.396
.450			0.075	.386	.385	.385	.385
.444			0.150	.398	.380	.378	.385
.412			0.300	.405	.385	.380	.390
.450			0.600	.383	.382	.375	.380
			1.200	.385	.379	.393	.386
			2.400	.440	.425	.441	.435
Mean			4.800	.442	.462	.456	.453
.429

Methanol reference      

90%-line .386

TT value 6035.842 mg/l

 

Prisorine 3505

TT value none

Validity criteria fulfilled:

yes

Conclusions:

All the extinction values measured for Prisorine 3505 lie close to the horizontal reference line, so no toxicity threshold (TT) value of Prisorine 3505 for Pseudomonas putida can be determined (Table 1). The TT value of methanol determined for Pseudomonas putida was 6036 mg/l . With respect to the known literature TT value of methanol (6600 mg/l) and considering the existing differences in definitions for the TT value in the literature concerned, it can he concluded that the test conditions were optimal and the results obtained are valid. The 18 h NOEC of the test substance to microorganisms was determined to be >4.8 mg/L (nominal).

Executive summary:

A study was conducted to determine the toxicity of the test substance to microorganisms according to DIN 38414. Pseudomonas putida bacteria were exposed to the test substance at nominal concentrations of 0.001, 0.002, 0.005, 0.009, 0.019, 0.038, 0.075, 0.150, 0.300, 0.600, 1.2, 2.4 and 4.8 mg/L for 18 h. In addition, one controls, and ten different concentrations of the reference substance methanol were tested. The extinction values at 436 nm were measured. The inhibitory effect of the test substance was expressed as a percentage of the mean extinction values of the controls. Up to and including the concentration of nominal 4.8 mg/L, the test substance had no inhibitory effect on Pseudomonas putida bacteria after the incubation period of 18 h. The extinction values of the positive control were in the range of known literature values for methanol compared to the controls confirming the suitability of the used bacteria. Under the study conditions, the 18 h NOEC of the test substance to microorganisms was determined to be >4.8 mg/L (nominal).

Description of key information

No toxicological effects on microorganisms are expected up to the limit of water solubility of Isooctadecanoic acid and similar obervations are expected for its potassium salts.
A study was conducted to determine the toxicity of the test source substance to microorganisms according to DIN 38414. Pseudomonas putida bacteria were exposed to the test substance at nominal concentrations of 0.001, 0.002, 0.005, 0.009, 0.019, 0.038, 0.075, 0.150, 0.300, 0.600, 1.2, 2.4 and 4.8 mg/L for 18 h. In addition, one controls, and ten different concentrations of the reference substance methanol were tested. The extinction values at 436 nm were measured. The inhibitory effect of the test substance was expressed as a percentage of the mean extinction values of the controls. Up to and including the concentration of nominal 4.8 mg/L, the test substance had no inhibitory effect on Pseudomonas putida bacteria after the incubation period of 18 h. The extinction values of the positive control were in the range of known literature values for methanol compared to the controls confirming the suitability of the used bacteria. Under the study conditions, the 18 h NOEC of the test substance to microorganisms was determined to be >4.8 mg/L (nominal).

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

4.8 mg/L