2,6-dimethyloctan-2-ol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August-September 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Test according to OECDTG202 from 1984. Only 3 test concentrations, no indication of method used to derive EC50 value. Analytical confirmation by means of TOC analysis. No CoA. No temperature at t=0h. No data on reference test.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Test concentrations were verified by chemical (TOC) analysis at 0, 24 and 48 hours for the test concentrations.
Water samples were also taken from the stock solution (t=0) and control (t=0).

Vehicle:

no

Details on test solutions:

A stock solution was prepared to give the desired series of test concentrations. To achieve this 240.1 mg of the test substance were added to 2 litres of dilution water and treated for 60 seconds with an ultra-turrax and afterwards stirred for 24 h an a magnetic stirrer.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: population of parthenogenetic females of synchronized age structure is maintained since more than 15 years in the test facility under constant
temperature conditions (20 +/- 1 °C) at a 16 : 8 hour light-dark photoperiod (illumination: < 1000 lux).
- Source: Bundesgesundheitsamt Berlin
- Age at study initiation: The neonates are separated from their parent Daphnia by filtration prior to the acute test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

14.6 °dH (corresponding to 260.6 mg/L CaCO3)

Test temperature:

t=0h not given
t= 24h 19.9 °C (100 mg/L treatment)
t= 48h 19.7, 19.8, 19.9°C in control, 25 mg/L and 50 mg/L treatment respectively

pH:

7.8

Dissolved oxygen:

8.6 mg O2/L controls at 48h
8.4 mg O2/L in the treatments

Nominal and measured concentrations:

Nominal test concentrations: 0, 25, 50 and 100 mg/I.
Mean measured test concentrations t=48 h: <2, 22.1, 44.2 and 86.5 mg/I respectively
Measured concentrations were used for the effect assessment because they ranged 88-94% of nominal at t=0h and 83-85% of nominal at 48h.
The effect concentration was determined as geometric mean of the EC0 and EC100 value.

Details on test conditions:

TEST SYSTEM
-three test concentrations plus one control each in duplicate (20 animals per test group).
Ten neonate Daphnia were placed in each Karlsruher Flaschen (closed bottles) containing 250-300 ml of prepared test medium.

Cultures were maintained at 20 +/-1 °C under a photoperiod of 16 hours light : 8 hours darkness.
No supplementary aeration or feeding during the 48 hour exposure period.
The temperature in each vessel was measured daily and the pH and dissolved oxygen levels recorded at 24h or 48h.

EFFECT PARAMETERS MEASURED: The criterion of adverse effects used in this study was the substance-induced alteration of the normal mobility
behaviour and the loss of locomotory actions of the neonates, observed at 24 and 48 hours.

Reference substance (positive control):

not specified

Key result

Duration:

48 h

Dose descriptor:

other: geometric mean of EC0 and EC100

Effect conc.:

43.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Measured concentrations ranged from 88-94 % of nominal at 0 hours and 83-85% of nominal at 48 hours.

Individual pH, temperature and dissolved oxygen values remained within acceptable limits throughout the duration of the study

Nominal conc	Total No. Immobilised T=24h	Total No. Immobilised T=48h	Total % immobilised
control	0	0	0
25 mg/L	0	0	0
50 mg/L	0	18	90
100 mg/L	20		100

Validity criteria fulfilled:

yes

Remarks:

as presented in OECD TG 202

Conclusions:

The acute EC50 for Daphnia tested in an OECD TG 202, is 43.7 mg/I based on mean measured concentrations.

Executive summary:

A study was performed to assess the acute toxicity of the substance to Daphnia magna. The study was conducted in accordance with OECD Guideline for Testing of Chemicals No. 202. Groups of twenty, neonate Daphnia were exposed for 48 hours to three concentrations of the substance dissolved in test water. The incidence of immobilisation was recorded for each test and control group at 24 hours and at 48 hours and the following values determined: geometric mean of EC0 and EC100 = 43.7 mg/L, assumed to represent the EC50. All 48h results are expressed in terms of mean measured concentrations. Measured concentrations ranged from 88 -94 % of nominal at 0 hours and 83 -85 % of nominal at 48 hours.

Description of key information

A study was performed to assess the acute toxicity of the substance to Daphnia magna. The study was conducted in accordance with OECD Guideline for Testing of Chemicals No. 202. Groups of twenty, neonate Daphnia were exposed for 48 hours to three concentrations of the substance dissolved in test water. The incidence of immobilisation was recorded for each test and control group at 24 hours and at 48 hours and the following values determined: geometric mean of EC0 and EC100 = 43.7 mg/L, assumed to represent the EC50. All 48h results are expressed in terms of mean measured concentrations. Measured concentrations ranged from 88 -94 % of nominal at 0 hours and 83 -85 % of nominal at 48 hours.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

43.7 mg/L

Additional information

The geometric mean value was used and was worse-case to an arithmetic mean value of the EC0 and EC100 value.