Octanoic acid

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

not reported

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

Original report not available and documentation insufficient for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The substance was tested on Artemia salina using the LC50 assay method.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Artemia salina

Test type:

not specified

Water media type:

saltwater

Limit test:

no

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

240 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: No test duration of this short-term test is given in the publication but is assumed that the test duration might be similar to the duration of the freshwater tests.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

not reported

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Hyale plumulosa was studied under static marine water conditions for 48 h.

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: octanoic acid was dissolved in artifical sea water by adding 10 g/L and mixing in an Erlenmeyer flask for 24 h with a magnetic bar at room temperature (25 ± 2 °C). Mixture was left still for a few hours and the upper layer was removed with a capillary pipette. The lower layer was used for testing.

Test organisms (species):

other: Hyale plumulosa (Gammarus)

Details on test organisms:

TEST ORGANISM
- Common name: Gammarus
- Length at study initiation: 5 mm
- Food type: commercial fish food until test started

ACCLIMATION
- Acclimation period: 2 weeks

Test type:

semi-static

Water media type:

saltwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

51 mg CaCO3/L

Test temperature:

25 ± 2°C

pH:

freshwater: 7.2
saltwater: 8.2

Dissolved oxygen:

If dissolved oxygen was < 60 % of air saturation, aeration was provided once for 5 min at 24 h intervals.

Salinity:

25 per mille

Nominal and measured concentrations:

Animals were exposed to a geometric series of concentrations of the test chemical (max. 1000 mg/L), but when LC50 values of the test chemicals were close to or higher than the saturated concentrations, animals were exposed only to the saturated solutions and the half-dilution of the saturated solutions.

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: 200 mL
- Renewal rate of test solution: after 24 h
- No. of organisms per vessel: 10 per test vessel
- Aeration: if oxygen saturation was < 60% of air saturation aeration for 5 min, 24 h interval

OTHER TEST CONDITIONS
- Photoperiod: 12 h light/12 h dark

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

128 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

15 Nov -17 Nov 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: stock solution (10 g/100 mL) was prepared while using ultrasound, aliquots were pipetted into test vessel and filled up with standard dilution water
- Controls: 1

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water-flea
- Source: in-house culture
- Feeding during test: none

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

14 °dH (80 mg Ca and 12.2 mg Mg/L)

Test temperature:

20.5 - 21.0 °C (room temperature)

pH:

4.7 - 8.1, this is out of the recommended range of 6 - 9

Dissolved oxygen:

76 - 85 %

Nominal and measured concentrations:

nominal: 10, 30, 100, 300, 1000, 3000, 10000 mg/L

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume of test vessel: glass beakers, covered with glass plates
- No. of organisms per vessel: 20
- No. of vessels per concentration: 1
- No. of vessels per control: 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deion. water with 294 mg CaCl2 * 2 H2O, 123 mg MgSO4 * 7 H2O, 63 mg NaHCO3, 5.5 mg KCl

OTHER TEST CONDITIONS
- Photoperiod: 16 h

EFFECT PARAMETERS MEASURED: immobility after 48 h

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

300 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

550 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: at concentrations of 1000, 3000 and 10000 mg/L all daphnids were unable to swim. At 100 mg/L, 5 % were unable to swim

Table 1: Immobilisation of daphnids [%] after 48 h

Nominal test concentration [mg a.s./L]	Immobilisation [%]
0 (control)	0
10	0
30	0
100	5
300	0
1000	100
3000	100
10000	100

Reference 4

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 May - 20 May 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

hardness of test water was lower than that recommended by the Guideline

GLP compliance:

yes

Remarks:

according to the Japanese GLP Standard

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Vapour pressure: 1 mm at 125 °C
- Water solubility: < 1 mg/L
- log Pow: 4.09

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 and 20 mg/L
- Sampling method: 10 mL test solution was sampled directly from each test vessel at test initiation and after 48 hours.
- Sample storage conditions before analysis: Analysis was conducted immediately after sampling, no storage.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was dissolved in vehicle, and this stock solution was diluted in dilution water and stirred for 1 hour.
- Controls: dilution water with/without vehicle
- Chemical name of vehicle: dimethylformamide
- Concentration of vehicle in test medium: 0.1 mL/L
- Evidence of undissolved material: not observed

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: Bred in-house (origin: Incorporated Administrative Agency, National Institute for Environmental Studies, Tsukuba, Japan)
- Age at study initiation: max 24 hours
- Feeding during test: no

ACCLIMATION
- Acclimation period: 2 - 4 weeks
- Acclimation conditions: same as test
- Type and amount of food: Chlorella vulgaris, 0.1 - 0.2 mg C/day
- Health during acclimation: 1% mortality was observed

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

55.2 mg/L (as CaCO3)

Test temperature:

19.8 °C (20 ± 1 °C )

pH:

7.7 - 8.1

Dissolved oxygen:

7.5 - 8.5 mg/L (> 60% of saturated oxygen)

Nominal and measured concentrations:

nominal concentration: 20 mg/L
measured concentration: 21 mg/L (geometric mean)

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL beaker
- Material, fill volume: glass, 100 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration: 4
- No. of vessels per control: 4
- No. of vessels per vehicle control: 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: charcoal-treated, dechlorinated and aerated tap water in Takarazuka, Japan
- Alkalinity: 55 mg/L
- Ca/Mg ratio: 16/3.3
- Culture medium different from test medium: same as test medium
- Intervals of water quality measurement: pH, oxygen content and temperature of test solutions were determined at test initiation and at the end of the study.

OTHER TEST CONDITIONS
- Photoperiod: 16 : 8 hours day-night regime

EFFECT PARAMETERS MEASURED: Mobility observed daily

TEST CONCENTRATIONS
- Justification for using less concentrations than requested by guideline: 20 mg/L was the maximum concentration to be dissolved uniformly in dilution water with vehicle (0.1 mL/L)
- Range finding study: performed
- Test concentrations: 20 mg/L
- Results used to determine the conditions for the definitive study: mobility inhibition was not observed

Reference substance (positive control):

yes

Remarks:

potassium dichromate (reagent grade)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 21 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: no abnormality was observed
- Mortality of control: 0%
- Other adverse effects control: not observed

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 0.54 mg/L for 48 hours

Table 1: Measured concentration of Decanoic acid during 48 hour exposure

Nominal Concentration (mg/L)	Measured Concentrations (mg/L)			Percent of nominal
	0 Hours (new)	48 Hours (old)	Mean
Control	<0.2	<0.2	-	-
Solvent Control	<0.2	<0.2	-	-
20	21	22	21	110

Table 2: Immobility of Daphnia magna

Nominal Concentration (mg/L)	Cumulative Number of Immobilised Daphnia (Percent Immobility)
	24 Hours	48 Hours
Control	0 (0)	0 (0)
Solvent Control	0 (0)	0 (0)
20	0 (0)	0 (0)

Reference 5

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Please refer to the category justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Source: CAS 334-48-5

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 21 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Source: CAS 334-48-5

Description of key information

EC50 (48 h) > 21 mg/L (meas. geom. mean) based on mobility of Daphnia magna (OECD 202); RA CAS 334-48-5

Additional information

Good quality read across data from decanoic acid are used as key information to assess the short-term toxicity of octanoic acid to aquatic invertebrates due to deficiencies of the available data on octanoic acid. Decanoic and octanoic acids are structurally very similar. Due to an increasing toxicity with increasing chain length from octanoic acid (C8) to lauric acid (C12) for aquatic invertebrates, the study using decanoic acid (C10) represents a worst case biological profile towards aquatic invertebrates for octanoic acid (C8).

The read-across study (Ministry of the Environment of Japan, 1999), with Daphnia magna, was conducted according to OECD 202. The test organism was exposed in a static system to a single test item concentration of 20 mg/L (nominal). The test substance was dissolved in 0.1 mL/L dimethylformamide. An analytical monitoring was performed via GC-MS. The study did not show any toxicity effects on the test organism and resulted in an EC50 (48 h) of > 21 mg/L (meas. geom. mean). Based on these data no toxicological effects on aquatic invertebrates are expected for octanoic acid up to 21 mg/L test concentration.

Supporting studies are available for freshwater and marine organisms conducted with octanoic acid. Two saltwater studies (1989 and 1970) are available with the test organisms Hyale plumulosa (Gammarid) and Artemia salina resulting in LC50 (48 h) of 128 mg/L and 240 mg/L, respectively. However, both studies were rated as insufficient for further assessment due to limited documentation. The last available supporting study (2001) was conducted with the freshwater organism Daphnia magna and nominal test item concentrations of up to 10000 mg/L were tested. The EC50 was found to be 550 mg/L.

In conclusion, octanoic acid shows no toxic effects up to a concentration of 21 mg/L as worst case, based on read-across data.