2-ethylhexanal

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: only short notice available

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-ethylhexanal

EC Number:

204-596-5

EC Name:

2-ethylhexanal

Cas Number:

123-05-7

Molecular formula:

C8H16O

IUPAC Name:

2-ethylhexanal

Details on test material:

- test substance: 2-ethylhexanal, CAS 123-05-7
- purity: > 97 %

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- analytical monitoring: Gas Liquid Chromatography of samples taken after  0 and 72 hours from freshly prepared media and after 24 and 96 hours from  expired media 

Test solutions

Vehicle:

yes

Details on test solutions:

- name of the vehicle: acetone/ tween 80
- preparation of test concentrations: the test substance was dissolved in a 1:99 v/v mixture of acetone/Tween 80 to give an initial stock solution  of 500 mg/ml
- serial dilutions of this stock were prepared to give the  desired nominal test concentrations; the final solvent concentration in  the test was 50 or 100 µl/l of test water 

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

- test fish: rainbow trout (Oncorhynchus mykiss)
- mean standard length: 4.9 +/- 0.28 cm
- mean weight: 1.9 +/- 0.27 g
- feeding was stopped 24 h prior to test start 

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Details on test conditions:

- test water: laboratory tap water, dechlorinated by activated carbon and softened by by paasage through an Elga(R) water  purification system
- (total hardness: 149 +/- 15 mg/l as CaCO3)
- test vessels: glass aquaria, covered with a glass lid to reduce losses  due to the volatile nature of the test compound
- test volume: 50 l
- test concentrations: 0 (control), 0 (solvent control), 1.0, 2.2, 4.6,  10 and 22 mg/l 
- No. of fish per concentration: 7 
- loading: 0.27 g/l
- photoperiod: 16 h light / 8 h dark
- temperature: 14 +/- 1 °C
- aeration: no
- medium renewal: daily
- test duration: 96 h
- observations: mortality and symptoms of distress after 3, 6, 24, 48, 72, and 96 h 
- measurements: pH, temperature, and oxygen content at test start and after 24, 48, 72, and 96 h
- statistics: calculation of LC50 and 95 % confidence limits according to  Thompson & Weil (1952)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

5.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 2

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

1.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 3

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

3.7 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 4

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

8.2 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Any other information on results incl. tables

Sublethal observations / clinical signs:

RS-Freetext:
The 96-h LC50 is 5.5 mg/l (geometric mean of 3.7 mg/l [LC0] and 8.2 mg/l  [LC100]). 

Mortality
---------
   Concentration (mg/l)        Cumulative mortality (n)
  nominal  mean measured      3h   6h  24h  48h  72h  96h
      0 (control)              0    0    0    0    0    0 
  0 (solvent control)          0    0    0    0    0    0
   1.0        0.81             0    0    0    0    0    0  
   2.2        1.8              0    0    0    0    0    0 
   4.6        3.7              0    0    0    0    0    0  
  10          8.2              0    0    0    7    7    7
  22         15                7    7    7    7    7    7

Abnormalities
-------------
In the 3.7 mg/l concentration (mean measured) increased pigmentation was  observed already shortly after test start (3 h). After 48 hours, nearly  all fish were lying on the bottom and 3 of 7 fish showed loss of  equilibrium.

Two of 7 fish were moribund after 24 hours in the 8.2 mg/l concentration.  From shortly after test start until found dead, increased pigmentation  was seen in nearly all fish and five of 7 fish were lying on the bottom  and shoed loss of equilibrium.     

The pH was between 7.3 and 7.6 in all test vessels at all
observation times. 

The oxygen content was > 7.5 mg/l in all test vessels at all observation  times. 

In all test vessels the temperature was 15 °C at test start and 14 °C  afterwards.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes