Decanoic acid

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

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:

Oryzias latipes was studied under static freshwater and 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: capric 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). The mixture was left still for a few hours and the upper layer was remoced with a capillary pipette. The lower layer was used for testing.
For the freshwater test decanoic acid was dissolved with Tween 80 (a dispersant).

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: Red killifish
- Source: commercial source
- Length at study initiation: approximately 2.5 cm
- Weight at study initiation: approximately 0.2 g
- Feeding during test: Feeding was stopped one day prior to the test.
- Food type: commercial fish food

ACCLIMATION
- Acclimation period: Although Oryzias latipes is a freshwater fish, it was used in a marine test. First the fish were kept under laboratory conditions in freshwater for more than 2 weeks. Then fish were acclimatised to sea water by changing salt concentrations from 0 to 10 per mille (kept at 10 per mille for more than 4 days), to 20 per mille (kept at 20 per mille for more than 4 days) and to the final salinity of 30 per mille (kept for more than 7 days before test start)

Test type:

static

Water media type:

other: both salt- and freshwater was tested

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 for 5 min at 24 h intervals.

Salinity:

30 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: 2 L test water
- Aeration: if oxygen saturation was < 60% of air saturation: aeration for 5 min, 24 h interval
- Renewal rate of test solution: no, static test
- No. of organisms per vessel: 10

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

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : lethal effects

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

31 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

mortality (fish)

Remarks on result:

other: in sea water

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

20 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

mortality (fish)

Remarks on result:

other: in freshwater

Remarks:

Tween 80 concentration was 15 times greater than the testing concentration

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

01 Dec - 03 Dec 1987

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Qualifier:

according to guideline

Guideline:

other: DIN 38412/15

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Leuciscus idus

Details on test organisms:

TEST ORGANISM
- Common name: Golden orfe
- Length at study initiation: about 6 cm
- Feeding during test: none

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

about 16 °dH (about 93 mg Ca and 12 mg Mg/L)

Test temperature:

19.5 - 20.5 °C

pH:

6.4 - 8.2

Dissolved oxygen:

30 - 98%
10 mg/L: 66- 98%, 30 mg/L: 35 - 96 %, 100 mg/L: 30 - 96%, 300 mg/L: 71 - 94%, 1000 mg/L: 81 -96%, 3000 mg/L: 90 - 94%, 10000 mg/L: 92 - 96%
The dissolved oxygen values for the 30 and 100 mg/L test solutions are considered to be too low (< 40%)

Salinity:

n.a.

Nominal and measured concentrations:

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

Details on test conditions:

TEST SYSTEM
- Test vessel: fish basin containing 10 L test water
- No. of organisms per vessel: 10
- No. of vessels per control: no control

OTHER TEST CONDITIONS
- Photoperiod: 16 h

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

LC0

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

95 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC100

Effect conc.:

300 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: none

Sublethal observations / clinical signs:

Table 1: Mortality [%] of fish

Concentration	Incubation time [h]
[mg prod./L]	0	6	24	48
10	0	0	0	0
30	0	0	0	0
100	0	0	20	20
300	0	100	100	100
1000	0	100	100	100
3000	0	100	100	100
10000	0	100	100	100

The dissolved oxygen contents were too low in several treatments.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

17 Nov - 21 Nov 1977

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Basic data given

Qualifier:

according to guideline

Guideline:

other: EPA-660/3-75-009, Methods for Acute Toxicity Tests with Fish Macroinvertebrates and Amphibians. 1975

Principles of method if other than guideline:

Acute (96h) toxicity test with Lepomis macrochirus conducted under static conditions.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

TEST ORGANISM
- Common name: bluegill sunfish
- Source: commercial hatchery in Nebraska (USA)
- Age at study initiation: 5 months old
- Length at study initiation: mean 34 mm (range 26 - 40 mm)
- Weight at study initiation: mean 0.41 g (range 0.29 - 0.52 g)
- Feeding during test: none

ACCLIMATION
- Acclimation period: 24 h

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

42 mg CaCO3/L

Test temperature:

23.0 ± 0.5 °C, determined at test start and every 48 h

pH:

5.50 - 7.47, determined initially and every 48 h in the control, 100 mg/L, 32 mg/L and 10 mg/L

Dissolved oxygen:

0.7 - 9.5 mg/L, determined initially and every 48 h in the control, high, medium and low toxicant concentrations

Nominal and measured concentrations:

nominal: 10, 18, 32, 56 and 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 5 gallon, chemically clean glass jars containing 15 L test medium
- No. of organisms per vessel: 10
- No. of vessels per concentration: 1
- No. of vessels per control: 1
- Biomass loading rate: 0.27 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: water obtained from a well on the Tarrytown site, treated with a Continental Reverse Osmosis water System, afterwards deionised, pH and hardness adjusted.

OTHER TEST CONDITIONS
- Adjustment of pH: yes

EFFECT PARAMETERS MEASURED: mortality and sublethal effects

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

18.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence interval: 15.6 - 22.8 mg/L

Details on results:

- Other biological observations: Fish exposed to concentrations of 18 mg/L and higher became darkly discoloured, irritated and exhibited sounding initially with surfacing behaviour after 72 h.
- Mortality of control: 0

Sublethal observations / clinical signs:

Table 1: Mortality of fish [%]

Time after test start [h]	Test substance concentration [mg/L]
	0	10	18	32	56	100
24	0	0	0	100	100	100
48	0	0	0	100	100	100
96	0	0	40	100	100	100

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

07 Jun - 11 Jun 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

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/L
- Evidence of undissolved material: not observed

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: Medaka
- Source: Izumoto fish shop
- Length at study initiation: 2.1 cm (2.0 - 2.3 cm)
- Weight at study initiation: 0.19 g (0.16 - 0.21 g)
- Feeding during test: no food

ACCLIMATION
- Acclimation period: > 12 days
- Acclimation conditions: same as test
- Type and amount of food: Tetramin
- Health during acclimation: No mortality was observed during 7 days before exposure.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96

Hardness:

55.2 mg/L (as CaCO3)

Test temperature:

23.3 - 23.9 °C (24 ± 1 °C)

pH:

7.5 - 8.1

Dissolved oxygen:

5.6 - 8.2 mg/L (more than 60% of saturated oxygen)

Nominal and measured concentrations:

nominal concentration: 20 mg/L
measured concentration: 16 mg/L (geometric mean)

Details on test conditions:

TEST SYSTEM
- Test vessel: 5L glass fish tank
- Material, size, headspace, fill volume: glass, 21*16*23 cm, 5 L
- Aeration: no
- Renewal rate of test solution: once in 48 hours
- No. of organisms per vessel: 10
- No. of vessels per concentration: 1
- No. of vessels per control: 1
- No. of vessels per vehicle control: 1

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 0, 24, 48 (both before and after renewal), 72 and 96 hours.


OTHER TEST CONDITIONS
- Photoperiod: 16 h light, 8 h dark

EFFECT PARAMETERS MEASURED: mortality 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 mg/L).
- Range finding study: performed
- Test concentrations: 0, 0.2, 2.0, 20 mg/L
- Results used to determine the conditions for the definitive study: no mortality and no toxicity was observed

Reference substance (positive control):

yes

Remarks:

copper sulfate pentahydrate (analytical grade)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 16 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no abnormality was observed
- Observations on body length and weight: not determined
- Other biological observations: no abnormality was observed
- Mortality of control: 0%
- Other adverse effects control: not observed
- Abnormal responses: not observed

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- LC50: 4 mg/L

Sublethal observations / clinical signs:

Table 1: Measured Concentratioin of Decanoic acid

Nominal Concentration (mg/L)	Measured Concentration (mg/L)			Percent of nominal
	0 Hours (new)	48 Hours (old)	Mean
Control	<0.2	<0.2	-	-
Solvent Control	<0.2	<0.2	-	-
20	23	11	16	80

new: Freshly prepared test solutions

old: Test solutions after 48 -hours exposure period

Table 2: Mortality of Medaka (Oryzias latipes)

Mean measured concentration (mg/L)	Cumulative Number of Dead Fish (Percent Mortality)
	24 Hours	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)
16	0 (0)	0 (0)	0 (0)	0 (0)

Description of key information

LC50 (96 h) > 16 mg/L (meas., geom. mean), based on mortality of Oryzias latipes

LC50 (96 h) = 18.9 mg/L (nominal), based on mortality of Lepomis macrochirus

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

18.9 mg/L

Additional information

Four studies with different reliabilities are available and provide in the frame of a WoE clear indications towards the short term toxicity of decanoic acid on fish.  

In the first study (1999) Oryzias latipes was exposed in a semi-static system to only one single test item concentration of 20 mg/L (nominal) for 96 h. The experiment was conducted according to OECD guideline 203 and GLP. The test substance was dissolved in 0.1 ml/L dimethylformamide. The concentration of the test item in the solutions was monitored by GC-MS over time. The mean recovery of the test item concentration was 80%. The study showed no effects on the test organism resulting in an LC50 (96 h) of > 16 mg/L (meas., geom. mean). However, this result is very possibly attributed to the low concentration tested, as supported by the further available studies which were performed with higher concentrations of the substance.

In the second available study (1977) Lepomis macrochirus, was exposed for 96 h in a static test regime to higher test concentrations than the first listed study (10, 18, 32, 56 and 100 mg/L nominal) showing toxicity effects. The study was performed according to EPA-660/3-75-009, Methods for Acute Toxicity Tests with Fish Macroinvertebrates and Amphibians (1975) and resulted in an LC50 of 18.9 mg/L (nominal). 

In a further study (2001) performed according to OECD guideline 203 and GLP, Leuciscus idus was exposed in a static system to nominal test item concentrations of 10, 30, 100, 300, 1000, 3000 and 10000 mg/L for 48 h. No analytical monitoring of the test item concentrations in the solutions was performed. The study showed biological effects resulting to an LC50 (48 h) of 95 mg/L (nominal). However, dissolved oxygen concentrations were too low in several treatments and no control was set up. Therefore, this study was assigned as not reliable (RL3) due to major scientific limitations but supports in the frame of a WoE the above described results.

The last available study (1989) was conducted with Oryzias latipes under static conditions in both fresh- and saltwater medium Fish were exposed for 48 h to a single test item concentration of 1000 mg/L (nominal). Biological effects were observed in both conditions and LC50 (48) values of 31 mg/L and 20 mg/L for salt- and freshwater respectively, were derived. Allthough the publication gives valuable information the documentation is inadequate for assessment purposes and the study was rated as RL4.

In conclusion, the sum of the available data gives clear evidence that short term toxicity of decanoic acid on fish is expected at concentrations higher than 18 mg/L. Effects did not occur in the first listed study (1999) due to the low tested concentrations.