Fatty acids, C8-10

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:

key study

Study period:

18 May - 20 May 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

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

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/LGC
- 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 2

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

Reason / purpose for cross-reference:

read-across source

Key result

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

Key result

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

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

550 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Source: CAS 124-07-2

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 the two main constituents (decanoic and octanoic acid) of the substance fatty acids, C8 -10 are used to assess the short-term toxicity to aquatic invertebrates.

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).

Supporting information are available from a study with the read across substance octanoic acid (2001). The test 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, no short term toxic effects to aquatic invertebrates up to a concentration of 21 mg/L as worst case is expected from fatty acids, C8 -10, based on read-across data.