Isooctyl acetate

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:

24 July 1985 - 26 July 1985

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

No guideline followed. Analytical verification not fully reliable.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1985

Report date:

1985

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

- Effect concentration based on % water soluble fraction (WSF)

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Isooctyl acetate

EC Number:

250-701-2

EC Name:

Isooctyl acetate

Cas Number:

31565-19-2

Molecular formula:

C10H20O2

IUPAC Name:

Acetic acid, isooctyl ester

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken from all test concentrations on Day 0, before adding test organisms. Day 1, and on day of termination. Samples were taken from the control, high and low test concentration, as well as the stock solution on Day -1. All BW2 used for test material preparation and all stock solutions were sampled during the study. All analyses were done by the Total Carbon method.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

The water soluble fraction of MRD-83-303 was prepared by combining the test material with BW2 at a ratio of approximately 6.7 ml test material:1 liter blend water. The mixture was then stirred for approximately 72 hours prior to use as the 100% stock solution. The water soluble fraction was drawn out of the mixing vessel by way of a sampling tube.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISMS
- Source: Cultured in the Environmental Toxicology Laboratory
- Number: 120
- Age: < 24 hours old
- Cultures of Daphnia were fed Selenastrum capricornutum and a trout chow mixture. The algae were cultured in the Aquatic Laboratory using modified ASM-1 media.

ENVIRONMENTAL CONDITIONS
- Test organisms were not fed during the study
- Daphnids are kept in 1 liter glass culture vessels with dilution water (BW2 at 21 ± 1°C)

ACCLIMATION
Daphnids were kept in 1 liter glass culture vessels with dilution water (BW2) similar to that which was used during the test phase. Daphnids were maintained at test temperature (21 +/- 1 degree C) for at least 48 hours prior to start of test

IN LIFE DATES
24 July 1985 - 26 July 1985

Study design

Test type:

flow-through

Water media type:

freshwater

Remarks:

Laboratory dilution water (Blend Water 2)

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

153 - 157 mg/L CaCO3

Test temperature:

21.7 - 22.3 C

pH:

7.5 - 8.1

Dissolved oxygen:

7.6 - 7.9 mg/l

Conductivity:

340-355 uhmos

Nominal and measured concentrations:

Nominal concentration (%WAF): 6.25, 12.5, 25, 50, 100
Measured concentration (as ppm TC): 1.87, 4.13, 10.24, 20.21, 39.95

Details on test conditions:

TEST SYSTEM
- Test vessel: The test chambers were constructed of glass and stainless steel
- Material, size, headspace, fill volume: The test chambers were constructed of glass and stainless steel with an approximate volume of 750 ml.
- Type of flow-through (e.g. peristaltic or proportional diluter): The MRD-83-303 test material water soluble fraction was administered in aqueous solution via a diluter system,
- Renewal rate of test solution (frequency/flow rate): Approximately 6 liters of test solution was delivered to each replicate test chamber per 24 hour period.


OTHER TEST CONDITIONS
- Photoperiod: Diumal light, approximately 16 hours light followed by 8 hours dark with a gradual intensity conversion between periods.
- Light intensity: Daylight intensity ranged from 83 to 87 footcandles as measured by computer IP 31.

RANGE-FINDING STUDY
- Test concentrations: Nominal (% WSF): 0, 6.25, 12.5, 25, 50, 100
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

73.58 other: % WSF

Details on results:

Test results were used to derive the 48-h EC50, defined as the calculated concentration of the test material which caused 50% mortality in the population of test organisms at the specified time of exposure. The statistical method used to calculate the LC 50 values was a Maximum Likelihood probit analysis based on D. J. Finney, 1971.

Any other information on results incl. tables

Table 1: Study observation data  Start time  Control  6.25  12.5  25  50  100  1045 (July 24)  0  0  0  0  0  0  1400 (July 24)  0  0  0  0  0  0  1700 (July 24)  1  1  0  0  0  0  1100 (July 25)  0  0  1  0  1  2  1045 (July 26)  0  0  0  0  2  15

Table 2: Results of water quality analysis  Sample  Sample date  Alkalinity (mg/l)  Hardness (mg/l)  Specific conductance (umho/cm)  Total organic carbon ppm  BW2  16 july 85  55  153  325  0.244  BW2  23 July 85  55  157  302  0.552

Table 2: Nominal and measured exposure concentrations  Nominal concentration (% WSF)  Measured Concentration (as ppm total carbon) (S.D)  6.25  1.87 (0.22)  12.5  4.13 (0.34)  25  10.24 (1.46)  50  20.21 (2.33)  100  39.95 (4.72)

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

A 48-h EC50 of 73.58 (%WSF) was determined for Daphnia magna. Based on the 48-h EC50, the test material is not classified as acutely toxic to aquatic invertebrates according to Regulation (EC) No. 1272/2008 (CLP).