Ethyl hexanoate

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:

2016-11-18 to 2017-04-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

2008

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.00, 2.50, 5.00, 10.0, 20.0 and 40.0 mg/L (nominal)
- Sample storage conditions before analysis: in the refrigerator at 6 +/- 2°C

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Appropriate volumes of the test item were pipetted directly into the test vessels filled with appropriate volumes of dilution water. The test media were mixed with an ultraturrax (1 min, 12000 rpm). This procedure was repeated for every water renewal.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebrafish
- Source: single brood stock (supplier: Umweltbundesamt, Schichauweg 58, D-12307 Berlin)
- Length at study initiation (length definition, mean, range and SD): mean: 2.76 cm
- Weight at study initiation (mean and range, SD): mean: 0.19 g
- Feeding during test: no

ACCLIMATION
- Acclimation period: at least 12 d
- Acclimation conditions (same as test or not): Same as test.
- Type and amount of food: Sera Vipan, 4% of fish body weight per feeding day
- Feeding frequency: 3 times/week
- Health during acclimation (any mortality observed): No mortality observed.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

65 mg CaCO3/L

Test temperature:

22.6 - 23.0°C

pH:

7.14 - 7.77

Dissolved oxygen:

81 - 100%

Nominal and measured concentrations:

Nominal: 0, 2.50, 5.00, 10.0, 20.0 and 40.0 mg/L
Measured: < LOQ, 1.31, 2.84, 5.25, 8.66 and 18.9 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass aquaria of 13 L were used, filled with approximately 10 L of dilution water (dimensions: 25.5/18/28 cm, depth of water: 20 cm) and covered with a floating lid (e.g. with aluminium foil), to reduce the loss of the test item.
- Type (delete if not applicable): semi-static (covered with aluminium foil)
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): daily
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: Fish density: 0.131 g fish/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap water of local origin
- Chlorine: filtered on activated charcoal and aerated for at least 24 hours to remove chlorine
- Hardness: 10 - 250 mg CaCO3/L
- pH: 6.0 - 8.5
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours/light
- Light intensity: mean value: 116 Lux.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality, visible abnormalities (e.g. loss of equilibrium, swimming behaviour, respiratory function, pigmentation, etc.) after 3, 24, 48, 72 and 96 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: yes
- Test concentrations: limit test with 16 mg/L (29 % mortality); complete response test. 0, 2.50, 5.00, 10.0, 20.0 and 40.0 mg/L (nominal)
- Results used to determine the conditions for the definitive study: yes, full test with 5 test concentrations.

Reference substance (positive control):

not required

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

6.74 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: calculated as mean from the values of LC0 and LC100

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

5.25 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

8.66 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: At a concentration level of 8.66 mg/L and 18.9 mg/L the fishes showed lethargy, took side positions, were staggering and were hyperventilating.
- Mortality of control: no
- Other adverse effects control: no

Sublethal observations / clinical signs:

Table 1: Cumulative mortality (%) (n=7)

Geometric mean measured concentration (mg/L)	Cumulative mortality (%) after different exposure periods (hours)
	3	24	48	72	96
18.9	0	100	100	100	100
8.66	0	0	14	100	100
5.25	0	0	0	0	0
2.84	0	0	0	0	0
1.31	0	0	0	0	0
Control	0	0	0	0	0

 

  Table 2: Environmental conditions

Exposure time (days)	Geometric mean measured concentration (mg/L)	Mean oxygen saturation (%)	pH value	Temperature (°C)
0	18.9	100	7.67	22.8
	8.66	100	7.71	22.8
	5.25	100	7.72	22.7
	2.84	100	7.77	22.8
	1.31	100	7.75	22.8
	Control	100	7.70	22.7
1	18.9	90	7.61	22.9
	8.66	94	7.64	22.9
	5.25	93	7.63	23.0
	2.84	94	7.60	23.0
	1.31	92	7.58	22.9
	Control	93	7.53	22.9
2	18.9	-	-	-
	8.66	91	7.66	22.8
	5.25	92	7.64	22.8
	2.84	93	7.62	22.8
	1.31	93	7.61	22.8
	Control	94	7.51	22.9
3	18.9	-	-	-
	8.66	87	7.40	22.8
	5.25	93	7.48	22.8
	2.84	93	7.45	22.9
	1.31	93	7.43	22.7
	Control	94	7.33	22.8
4	18.9	-	-	-
	8.66	-	-	-
	5.25	82	7.44	22.7
	2.84	88	7.53	22.6
	1.31	88	7.53	22.8
	Control	88	7.55	22.7

- no measurements due to 100% mortality

Table 3: Measured Concentrations and Percent of the Nominal Concentrations of the Test Item 

Sampling date	2017-02-20 0 h (Fresh medium)		2017-02-21 24 h (Old medium)		2017-02-23 72 h (Fresh medium)		2017-02-24 96 h (Old medium)
Nominal concentration of the test item [mg/L]	Meas. concentration [mg/L]	%	Meas. concentration [mg/L]	%	Meas. concentration [mg/L]	%	Meas. concentration [mg/L]	%	Geometric mean measured concentration [mg/L]
40.0	24.2	61	14.7	37	1)				18.9
20.0	11.8	59	6.37	32	1)				8.66
10.0	7.75	78	4.40	44	6.26	63	3.56	36	5.25
5.00	3.45	69	2.47	49	3.23	65	2.36	47	2.84
2.50	1.57	63	1.05	42	1.54	62	1.18	47	1.31
Control	< LOQ		< LOQ		< LOQ		< LOQ		< LOQ

Meas. concentration = Measured concentration of the test item, enrichment factor taken into account

% = Percent of nominal concentration of the test item

LOQ = Limit of Quantification (0.2 mg/L test item)

1) = Not analyzed due to 100% mortality after 24 hours

Validity criteria fulfilled:

yes

Conclusions:

LC50 (96 h): 6.74 mg/L based on mortality of Danio rerio (OECD 203).
The toxicity of Ethyl hexanoate to fish (Danio rerio, Zebrafish) was determined in a GLP study according to OECD 203. The LC50 of 6.74 mg/L was calculated from the geometric mean measured values of the LC0 and the LC100.

Description of key information

LC50 (96 h): 6.74 mg/L based on mortality of Danio rerio (OECD 203)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

6.74 mg/L

Additional information

The toxicity of the test item to fish was determined in a semi-static test performed according to OECD 203 and GLP. Individuals of Danio rerio were exposed to nominal test concentrations of 2.50, 5.00, 10.0, 20.0 and 40.0 mg/L, equivalent to geometric mean measured concentrations of  1.31, 2.84, 5.25, 8.66 and 18.9 mg/L. The test concentrations were analysed by GC-FID daily. After 96 h 100% mortality was observed at 8.66 mg/L, whereas 0% mortality was recorded at 5.25 mg/L. The LC50 (96 h) was calculated at 6.74 mg/L (measured).