Docosanoic acid

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 May - 15 May 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Remarks:

According to Japanese GLP standard

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Test water was directly sampled by each vessel.
- Sample storage conditions before analysis: No storage before analysis.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test item was mixed with HCO-20 and diluted with dilution water (stock solution: 100 mg/L).
- Controls: Blank control and vehicle control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): HCO-40
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 2000 mg/L in stock solution and 100 mg/L in final test solution

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: Medaka fish
- Source: Sankyo Suisan Company, Shinjuku, Japan
- Length at study initiation (length definition, mean, range and SD): 2.33 cm (2.16 - 2.49 cm)
- Weight at study initiation (mean and range, SD): 0.226 g (0.162 - 0.318 g)
- Feeding during test: No food

ACCLIMATION
- Acclimation period: 27 February - 11 May 1998
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: Tetramin
- Health during acclimation (any mortality observed): Mortality was < 5% during 7 days before exposure

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

63 mg/L as CaCO3

Test temperature:

23.5 - 24.2 °C

pH:

7.2 - 7.8

Dissolved oxygen:

5.2 - 8.3 mg/L

Nominal and measured concentrations:

Nominal concentration: 5 mg/L
Measured concentration: 4.93 mg/L (geometric mean)

Details on test conditions:

TEST SYSTEM
- Test vessel: Beaker
- Type (delete if not applicable): closed with teflon sheet
- Material, fill volume: Glass, 5 L
- Aeration: No
- Renewal rate of test solution (frequency/flow rate): Every 24 hours
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: charcoal-treated, dechlorinated and aerated tap water in Yokohama, Japan
- Alkalinity: 44 mg/L
- Ca/mg ratio: 17/4.9
- Culture medium different from test medium: Same medium

OTHER TEST CONDITIONS
- Photoperiod: 16 hours in the light, 8 hours in the dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
General condition and mortality were observed everyday.

TEST CONCENTRATIONS
- Range finding study: Perfomed
- Test concentrations: 5 mg/L
- Results used to determine the conditions for the definitive study: Mortality for 96 hours was 0%.

Reference substance (positive control):

yes

Remarks:

copper sulfate pentahydrate (analytical grade)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: No abnormality was detected in all groups.
- Mortality of control: 0% both in blank control group and in vehicle control group
- Other adverse effects control: No adverse effects were detected.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- LC50: 0.73 mg/L

Sublethal observations / clinical signs:

Table 1. Mortality of Medaka fish

Nominal concentration (mg/L)	Mean measured concentration (mg/L)	Cumulative mortality
		24 Hour	48 Hours	72 Hours	96 Hours
Control	-	0 (0)	0 (0)	0 (0)	0 (0)
Solvent control	-	0 (0)	0 (0)	0 (0)	0 (0)
5	4.93	0 (0)	0 (0)	0 (0)	0 (0)

Validity criteria fulfilled:

yes

Description of key information

No short-term toxicity effects up to the limit of water solubility 

Additional information

One study is available on the toxicity of docosanoic acid (CAS 112-85-6) on fish.

The 96 h test provided by the Ministry of the Environment, Government of Japan (1998) was conducted according to OECD 203 and in accordance with GLP requirements. Medaka (Oryzias latipes) were exposed to docosanoic acid under semi-static conditions in a limit test by using a solvent. Since no mortality was observed the LC50 (96 h) was determined to be > 5.0 mg/L based on nominal concentrations (geometric mean measured concentration: 4.93 mg/L). Thus no effects could be observed within the range of water solubility, which is determined to be 0.016 mg/L.

Based on the results of that study it can be concluded that no acute toxic effects of docosanoic acid on fish are expected up to the limit of water solubility.