2-butoxyethyl benzoate

Long-term toxicity to fish

Administrative data

Endpoint:

fish, juvenile growth test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 204 (Fish, Prolonged Toxicity Test: 14-day Study)

Deviations:

no

Principles of method if other than guideline:

not applicable

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-butoxyethyl benzoate

EC Number:

226-685-8

EC Name:

2-butoxyethyl benzoate

Cas Number:

5451-76-3

Molecular formula:

C13H18O3

IUPAC Name:

2-butoxyethyl benzoate

Test material form:

other: clear liquid

Details on test material:

- Name of test material (as cited in study report): 2-butoxyethyl benzoate (Butyl Cellosolve™ Benzoate)
- Physical state: clear liquid
- Analytical purity: 99.2%
- Lot/batch No.: 20130443-19
- Expiration date of the lot/batch: 02 April 2016
- Storage condition of test material: Ambient

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
1st range finding study (sem-static) - control, 1, 10, 50 and 100 mg/l
2nd range finding study (semi-static and sterile water) - blank control, sterile test water control, 1.2, 2.0, 3.5, 5.9 and 10.0 mg/l
Definitive test - blank control, sterile test water control, 0.38, 0.65, 1.10, 1.90 snd 3.00 mg/l
- Sampling method: The test samples were taken directly from test water of the tests.
- Sample storage conditions before analysis: The samples were stored in refrigerator (5 ± 3 °C) after pre-treatment in case the samples were not analysed directly within 24 hours

Test solutions

Vehicle:

no

Details on test solutions:

To minimize the variability of the concentration of the test substance, sterile test water (test water autoclaved at 121 °C for 20 min) was used in the test solution preparation. The test substance was added in sterilized water and stirred (magnetic stirrer) in the dark for 24 hours at 5000 rpm to prepare a stock solution with a nominal concentration of 100 mg/l. The test solutions were prepared by dilution of the stock solution with test water.

Test organisms

Test organisms (species):

other: Gobiocypris rarus

Details on test organisms:

TEST ORGANISM
- Common name: Chinese rare minnow
- Strain: rarus
- Source: in house bred
- Water: the test water, tap water dechlorinated by activated carbon and sterilized by UV lamp was used
- Temperature: 21-25 °C and constant within a range of 2 °C
- pH: 6.0-8.5
- Oxygen concentration: > 80% ASV
- Photoperiod: 12 hours light/dark cycle
- Feeding: fishes were fed with Brine Shrimp Aquarium Flake Food, O.S.I® daily.

ACCLIMATION
- Acclimation period: more than 14 days
- Health during acclimation (any mortality observed): none noted

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

14 d

Post exposure observation period:

not applicable

Test conditions

Hardness:

Total hardness - 145 mg CaCO3/l

Test temperature:

20.0 - 23.3 °C

pH:

7.6 - 7.88

Dissolved oxygen:

Oxygen concentrations - > 90% ASV (76.3% - 99.3% ASV)

Salinity:

not applicable

Nominal and measured concentrations:

Control group and sterilized test water control group - 0,
0.3 mg/l - 0.147 mg/l (mean time- weighted average)
0.5 mg/l - 0.240 mg/l (mean time- weighted average)
0.9 mg/l - 0.409 mg/l (mean time- weighted average)
1.7 mg/l - 1.41 mg/l (mean time- weighted average)
3.0 mg/l - 2.54 mg/l (mean time- weighted average)

Details on test conditions:

TEST SYSTEM
- Test vessel: 5 litre glass tanks containing 4 litres test solution were used
- No. of organisms per vessel: 5 fish/vessel
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- Biomass loading rate: about 0.178 g - 0.179g fish/litre

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The fish were inspected once for mortality and other observed effects, measurements of pH, dissolved oxygen and temperature were carried out twice a week.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

0.147 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Effect concentrations 2

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

0.338 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 0.287 - 0.416 mg/l

Details on results:

- Mortality -
Control group - 0 (cummulative mortality %)
Sterilized test water control group - 0 (cummulative mortality %)
0.147 mg/l - 0 (cummulative mortality %)
0.240 mg/l - 13.3 (cummulative mortality %)
0.409 mg/l - 73.3 (cummulative mortality %)
1.41 mg/l - 100 (cummulative mortality %)
2.54 mg/l - 100 (cummulative mortality %)

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

Standard statistical methods were employed

Any other information on results incl. tables

None

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the tested conditions the LC50 of Gobiocypris rarus exposed to the test substance for 14 days was 0.338 mg/L with 95% confidence interval (CI) of 0.287-0.416 mg/L; the no obsersed effect concentration (NOEC) was 0.147 mg/L; the threshold level of the lethal effect was 0.240 mg/L.

Executive summary:

According to "Ministry of environmental protection of the people's Republic of China, The Guidelines for the Testing of Chemicals-Effects on Biotic System, 2013, 204 Fish Prolonged Toxicity Test: 14-day Study", the prolonged toxicity of the test substance, 2-Butoxyethyl benzoate (DOWM2014041 0-0882), to Gobiocypris rarus was determined by a semi-static test. The test substance was added in sterilized test water (test water autoclaved at 121°C for 20 min) and stirred (via magnetic stirrer) in the dark for 24h at 500 rpm to prepare a stock solution with a nominal concentration of 100 mg/L. The test solutions were prepared by dilution of the stock solution with test water. Based on the results of fish acute toxicity test with the same test substance, five treatment groups, a sterilized test water control group and a control group were included in the test. The nominal concentrations of the treatment groups were 0.3, 0.5, 0.9, 1.7 and 3.0 mg/L, which the time-weighed mean measured concentrations were 0.147, 0.240, 0.409, 1.41 and 2.54 mg/L, respectively. All treatment groups, sterilized test water control group and control group had 3 replicates each containing 5 fish. The frequency of the test solution renewal was 24h and the test duration was 14 days. The mortality in the control group and sterilized test water control group were both zero at the end of the test and the dissolved oxygen concentration was greater than 60.0% of the air saturation value (ASV) throughout the test. So the test was considered to be valid. Results from the UPLC analysis of the test solutions showed that the measured concentrations of the newly prepared (renewal) test solutions varied less than ± 20% of their geometric mean measured concentrations during the test. However, though measures were taken to prevent degradation of the test substance in the test solutions (e.g. 24-h renewals in clean vessels, stock solutions prepared in sterile water), the measured concentrations of the test substance declined and varied more than 20% over the renewal periods (old test solutions). Thus, results were expressed as the time-weighed mean measured concentrations. Under the tested conditions, the LC50 of Gobiocypris rarus exposed to the test substance for 14 days was 0.338 mg/L with 95% confidence interval (CI) of 0.287-0.416 mg/L; the no obsersed effect concentration (NOEC) was 0.147 mg/L; the threshold level of the lethal effect was 0.240 mg/L.