2-ethylhexyl nitrate

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:

2010

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 (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

As mortality occurred at the limit test concentration (LS) on day 1, sampling was stopped and a full definitive test was undertaken.

The sampling were performed by the Principal Investigator then sent to the test facility for analysis. The samples were analysed within 5 days after sampling according to the validated method.

Test item was stored at room temperature in poison cabinet.

Vehicle:

no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Conditions of housing:
Temperature: at 23°C ± 2°C.
Light: light/dark cycle 16/8 hours.
Freshwater (see chapter 12.1.1.).
Forced aeration to keep the dissolved oxygen concentration at or above 80% of the saturation value at the selected temperature.
Feeding : twice daily with tropical fish chow.

Acclimation period:
All fish were held in the laboratory where the study phase was performed seven days before the start of the range finding test. During the acclimation period, fish were subjected to the same conditions of housing (i.e. temperature, photoperiod, oxygen content and feeding). The feeding was stopped 24 hours before the start of the test.
One fish for four hundred received is dead during the last week before the test, the batch was agreed to be conformed.
Mortality was less than 5% for the 7 first days.

Sensibility of the batch was checked by a toxicity test with reference item (K2Cr2O7) at tow concentrations (200 and 400 mg/L). We have observed twenty nine percent mortality with 200 mg/L condition and one hundred percent mortality with 400 mg/L condition after 24h exposure. So, LC50(24h) K2Cr2O7 is between 200 and 400mg/L. The batch was agreed to be conformed.
LC50(24h) K2Cr2O7 was between 200 and 400mg/L.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

T0 (08/23/2010)= 23 °F
T96h (08/27/2010) = 22.3 °F

Test temperature:

23°C ± 2°C

pH:

From 7.05 to 8.12

Dissolved oxygen:

From 35.70 to 98.60

Nominal and measured concentrations:

0.92, 1.46, 2.34, 3.75 and 6 mg/L

Details on test conditions:

The aim of this study phase was to perform acute toxicity test to the zebra fish under semi-static conditions.

Tow essay were performed, one range finding test and one definitive test. In the definitive test fishes were exposed to five concentrations (0.92 ; 1.46 ; 2.34 ; 3.75 and 6 mg/l nominal concentration). In each condition, before and after renewal, sample were taken for essay item extraction in toluene and sent to CIT for analysis. At the beginning of the test seven fish were introduced in each vessel felled with essay solution and caped to avoid to important degradation of the essay item.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

1.52 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Validity criteria
All validity criteria of the study were respected.

Chemical analysis
Measured concentrations in the definitive test solutions at 0.92 and 1.46 mg/L were below the limit of quantification (< 0.8 mg/L) or detection (< 0.2 mg/L).
Measured concentrations in the definitive test solutions at 2.34, 3.75 and 6.00 mg/L dropped below 80% of the corresponding nominal values during the study, therefore the toxicity results were based on geometric means of measured concentrations during the corresponding exposure period, i.e. 96 hours.

Mortality
At T96 hours, mortality was 100% at the nominal concentration of 6 mg/L and 0% in all other tested concentrations. Hence, the 96-hour LC50 corresponds to the geometric mean of the highest concentration causing no mortality (3.75 mg/L nominal) and the lowest concentration producing 100% mortality (6 mg/L nominal). These concentrations were also used as confidence limits.

Sublethal observations / clinical signs:

At T96 hours,mortality was 100% at the nominal concentration of 6 mg/L and 0% in all other tested concentrations. Hence, the96-hourLC₅₀corresponds to the geometric mean of the highest concentration causing no mortality (3.75 mg/L nominal) and the lowest concentration producing 100% mortality(6 mg/L nominal). These concentrations were also used as confidence limits.

 

The results and conclusions are summarized in the following tables:

Group	Control		2-Ethylhexyl nitrate
	Nominal concentration (mg/L)
	0		0.92	1.46	2.34	3.75	6.00
	Measured concentration (mg/L)
Geometric mean 0-96 hours	0	ND		ND	1.04	1.52	2.64
	Effects
Mortality (%) - 96 hours	0		0	0	0	0	100

	Endpoints (mg/L)(1)
LC50- 96 hours	2.00 (1.52 - 2.64)
LC0- 96 hours	1.52
NOEC - 96 hours	1.52

Validity criteria fulfilled:

yes

Conclusions:

In a 96-hour semi-static acute toxicity test with Danio rerio, the LC50 of 2-Ethylhexyl nitrate was 2.00 mg/L.

The No Observed Effect Concentration NOEC was 1.52 mg/L.

Description of key information

In a 96-hour semi-static acute toxicity test with Danio rerio, the LC50 of 2-Ethylhexyl nitrate was 2.00 mg/L.

The No Observed Effect Concentration NOEC was 1.52 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

2 mg/L