Isopropyl 2-methylbutyrate

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:

08 to 10 Auguist 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Toyo Gosei Co., Ltd.; H4-K-27
- Expiration date of the lot/batch: 17 Aug 2018
- Purity test date: no data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Ambient temperature, no protection from light.
- Stability under test conditions: Stable
- Solubility and stability of the test substance in the solvent/vehicle:
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: no
- Preliminary purification step (if any):
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid:

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0, 1, 3.2, 10, 32 and 100 mg/l
- Sampling method: no data
- Sample storage conditions before analysis: ambient

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
- Eluate: Water
- Differential loading: 3.2
- Controls: Yes
- Chemical name of vehicle (organic solvent, emulsifier or dispersant):
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)):
- Evidence of undissolved material (e.g. precipitate, surface film, etc.):
- Other relevant information:

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone: Clone of genotype 5
- Justification for species other than prescribed by test guideline:
- Age at study initiation (mean and range, SD): <= 24 h
- Source: From cultures maintained at Chemex Environmental International Ltd since July 2014
- Age of parental stock (mean and range, SD):
- Feeding during test : no
- Food type: suspension of Chlorella vulgaris.
- Amount: no data
- Frequency: ad libitum

ACCLIMATION
- Acclimation period: minimal
- Acclimation conditions: same as test:
- Type and amount of food: suspension of Chlorella vulgaris.ad libitum
- Feeding frequency: daily
- Health during acclimation: no mortality observed

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Remarks on exposure duration:

Standard length for this study.

Test temperature:

20°C

pH:

6.6 - 7.4

Dissolved oxygen:

6.04 - 7.15 mg/L

Nominal and measured concentrations:

0 (control), 1, 3.2, 10, 32, and 100mg/l
0 (control, 0.394, 1.060, 3.397, 9.615 and 36.796 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml Wheaton bottle
- Type: closed
- Material, fill volume: 100 mL
- Volume of solution: 100 mL
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): no
- Renewal rate of test solution (frequency/flow rate): no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): n/a
- Biomass loading rate:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted Elendt M4 media prepared according to OECD 202.
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Salinity:
- Culture medium different from test medium:
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16 Hours Light, 8 Hours Dark Cycle
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

VEHICLE CONTROL PERFORMED: not applicable

RANGE-FINDING STUDY
- Test concentrations: 0 (control), 0.1, 1, 10 and 100mg/l.
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 36.796 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Confidence limits not possible to determine.

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

36.796 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Normality of distribution and equality of variances could not be confirmed.

Details on results:

The Daphnia were examined at 24-hours and 48-hours for abnormal behaviour during the determination of immobility. Abnormalities were observed during the test period one individual at 1.060mg/l and two individuals at 36.796mg/l showed slower movement at 24 hours. Two individuals in the control, one in 0.394, 1.060 and 9.615mg/l and eight individuals in 36.796mg/l showed slower movement at 48 hours. One individual was trapped in the meniscus and had slower movement in the control, four individuals were trapped in the meniscus and had slower movement at 0.394mg/l and one individual was trapped in the meniscus and had slower movement at 36.796mg/l at 48 hours.
No test concentration immobilised all twenty Daphnia after 48-hours. The highest concentration where no immobilisation occurred was 9.615mg/l.

Validity criteria fulfilled:

yes

Conclusions:

The 24-hour EC50 and 48-hour EC50 of Isopropyl 2-methylbutyrate to Daphnia magna were >36.796mg/l and >36.796mg/l (determined by Shapiro-Wilk’s test)) respectively.
The 0 to 24-hour NOEC and LOEC were 36.796mg/l and >36.796mg/l respectively (determined by Steel's Many-One Rank Test).
The 0 to 48-hour NOEC and LOEC were 36.796mg/l and >36.796mg/l respectively (determined by Steel's Many-One Rank Test).

Description of key information

The 24-hour EC50 and 48-hour EC50 of Isopropyl 2-methylbutyrate to Daphnia magna were > 36.796 mg/l and > 36.796 mg/l (determined by Shapiro-Wilk’s test)) respectively.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

36.796 mg/L