1-bromohexane

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 4th to September 10th 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted following official guidelines. No deviations were observed during the study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-bromohexane

EC Number:

203-850-2

EC Name:

1-bromohexane

Cas Number:

111-25-1

Molecular formula:

C6H13Br

IUPAC Name:

1-bromohexane

Test material form:

other: Liquid

Details on test material:

Lot number: 1-128-1
Main caracteristics:
- appearence : colorless liquid
- purity: 98.35%
- solubility: < 1 g/L in water

Test solutions

Vehicle:

yes

Details on test solutions:

Ultrapur water
Water was ultrafilterd, passed on active carbon and ion exchnge resin then filtered on a 0.22 µm filter

A saturated solution was prepared by puting 100 mg of test substance in test medium solution under agitation during 24 hours at a temperature of 20°C.
Excess of test substance was eliminated by phase separation after 30 min decantation.

The solutions with the concentration range, between 0.1 to 100% vol, were prepared by diluting the saturated solution with test medium solution.

Test medium solution was prepared following ISO 6341 norm.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna Straus (Cladocera, Crustacea) cultived by the laboratory in Elendt M7 medium with Raphidocelis subcapitata as feed supplement.
Organisms of less than 24 hours were selected by screening.

Study design

Test type:

static

Water media type:

saltwater

Total exposure duration:

48 h

Test conditions

Hardness:

Sum Ca + Mg = 2.5 mmol/L
Ca/Mg = 4 and Na/K = 10

Test temperature:

Between 19 and 21°C

pH:

Ph range between 7.99 to 8.08

Dissolved oxygen:

Concentration of O2 after 48 hr : between 8.3 to 8.8 mg/L

Nominal and measured concentrations:

Measured concentrations were maintened at 80% above initial concentration

Details on test conditions:

4 flasks of 5 Daphlia magna were prepared for each concentration and for the control test
Flasks were stored in darkness
Flasks were entirely filled with test solutions and closed with butyl rubber caps covered with PTFE

Reference substance (positive control):

yes

Remarks:

Potassium dichromate: CE50-24hr = 0.89 mg/L

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

7.6 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4.1 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 3.3 to 5 mg/L

Results with reference substance (positive control):

Immobilsation after 48 hours at 10%

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

1-Bromohexane have a CE50-24hr of 7.6 mg/L and a CE50 48hr of 4.21 mg/L. It has been to be classify as Dangerous for environment Tox 2

Executive summary:

The acute toxicity (inhibition of mobility) of 1-Bromohexane for Daphnia magna was assessed according to the C2 method of the European Directive 92/69/CEE. The study was carried out in compliance with the Principles of OECD Good Laboratory Practices.

Since 1-Bromohexane is sparingly soluble, the test was carried out with concentrations up to the water solubility. Daphnia were exposed in a static test to a concentration range of 3.5 to 100%. The test was performed with 5 daphnia per vessel and 20 daphnia per concentration. Since 1-Bromohexane is volatile, the test was performed using closed flasks as test glassware. In order to avoid volatilisation of 1-Bromohexane, flasks were entirely filled with test solutions and closed with butyl rubber caps covered with PTFE.

For each exposure concentration, the percentage of immobilization at 24 hours and 48 hours was recorded. The test concentrations of 1-Bromohexane were measured by GC. EC50-24hr and EC50-48hr were calculated with measured initial concentrations by regression analysis using the Probit/log model.

The EC50-24hr was calculated to be 7.6 mg/L.

The EC50-48hr was calculated to be 4.1 mg/L with 95% confident interval ranging from 3.3 to 5 mg/L.

The method was applied with respect to its quality criteria:

- immobilization in the control did not exceed 10% at the end of the test;

- concentration of dissolved oxygen in the test vessels remained above 2 mg/L at the end of the test and pH did not varied more than 1 unit;

- the concentrations of the test substance have been maintained to within 80% of the initial concentration throughout the duration of the test.