3-Butoxy-7-ethoxy-4,6-difluoro-dibenzothiophene

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jun 27 - Oct 17, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The study was conducted for a registration in a non-EU country.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Principles of method if other than guideline:

none

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

at 0 and 96 h

Vehicle:

no

Details on test solutions:

Dechlorinated drinking water sterilized by UV lamp is used in the test. The water was aerated continuously over 24h.

Test organisms (species):

other: Gobiocypris rarus

Details on test organisms:

The test was performed with Gobiocypris rarus which were obtained from the Institute of Hydrobiology, Chinese Academy of Sciences (ID: GR-SAPM-150901). This freshwater fish species is suitable for fish toxicity testing because of their ease of culturing and handling, sensitivity to a variety of chemical substances, and the extensive data base for this species. This species complies with Ministry of environmental protection of the people's Republic of China, The Guidelines for the Testing of Chemicals-Effects on Biotic System, 2013, 203 Fish, Acute Toxicity Test, OECD, Guidelines for the Testing of Chemicals. 203 Fish, Acute Toxicity Test, 1992
and GB/T 29763-2013 Chemicals-Rare Minnow (Gobiocypris rarus) acute toxicity test.

For evaluation of the fish quality and experimental conditions, potassium dichromate was tested as a positive control to demonstrate satisfactory test conditions once a year(recently performed on 2015.7.7-7.11). The 96h LC50 value of the test substance to Gobiocypris rarus was 153mg/L(95% confidence limits: 119-195mg/L), which was within the ± 2SD range of the QC chart in our lab(81.6-307g/L).

Photoperiod: Light/Dark= 12 hours/12 hours;
Feeding: fish were fed with brine shrimp flake (O.S.I®, USA) daily until 24 hours before the test was started.
Length was 2.5 ± 0.1 cm (Mean ± SD) and weight was 0.28±0.05 g (Mean ± SD) at the end of the test.
No diseases were observed during the acclimation period;
No mortality was present within the 7 days before the start of the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Remarks on exposure duration:

renewal every 24 h

Test temperature:

21 - 25 °C

pH:

6 to 8.5

Dissolved oxygen:

> 80 %

Nominal and measured concentrations:

A nominal concentration of 100 mg/L of the test substance was prepared and stirred (via magnetic stirrer) in the dark for 72h at 500rpm followed by filtration using a 0.45μm nitrocellulose membrane to make a saturated solution of the test substance in the test water (referred to as "saturated solution" in this report). Based on the results of the range-finding test, the saturated solution was used to perform the limit test with a blank control.

Details on test conditions:

none

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: < 0.505mg/L (LOD)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: < 0.505mg/L (LOD)

Details on results:

There were no mortalities and abnormalities observed in treatment group during the test period. No mortality occurred in the control during the test and the dissolved oxygen concentration was greater than 60.0% of the air saturation value (ASV) throughout the test duration. Hence, the test was considered tobe valid.

During the test, the measured concentrations of the test substance were below the limit of detection (LOD, LOD=0.505mg/L) by gas chromatograph (GC) method. There was no acute toxicity of the saturated solution in the limit test. The 96h LC50 of the test substance to Gobiocypris rarus was higher than the concentration of the saturated solution (the measured concentration was below the LOD, LOD=0.505mg/L) under the tested conditions.

Results with reference substance (positive control):

For evaluation of the fish quality and experimental conditions, potassium dichromate was tested as a positive control to demonstrate satisfactory test conditions once a year(recently performed on 2015.7.7-7.11). The 96h LCso value ofthe test substance to Gobiocypris rarus was 153mg/L (95% confidence limits: 119-195mg/L), which was within the + 2SD range of the QC chart in our lab (81.6-307mg/L).

Validity criteria fulfilled:

yes

Conclusions:

The 96h LC50 of the test substance to Gobiocypris rarus was higher than the concentration of the saturated solution (the measured concentration was below the LOD, LOD=0.505mg/L) under the tested conditions.

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, 203 Fish, Acute Toxicity Test", "OECD, Guidelines for the Testing of Chemicals. 203 Fish, Acute Toxicity Test, 1992" and "GBIT 29763-2013 Chemicals-Rare Minnow (Gobiocypris rarus) acute toxicity test", the acute toxicity of the test substance to Gobiocypris rarus was determined by a static test.

A nominal concentration of 100mg/L of the lest substance was prepared ancl stirred (via magnetic stirrer) in the dark for 72h (the vortex depth was 1 /3 of that of the mixture column) followed by filtration using a 0.45μm nitrocellulose membrane to make a saturated solution of the test substance in the test water (referred to as "saturated solution" in this report). Based on the results of the range-finding lest, the saturated solution was used to perform the limit test with a blank control. The test duration was 96h.

There were no mortalities and abnormalities observed in treatment group during the test period. No mortality occurred in lhe control during the lest and the dissolved oxygen concentration was greater than 60.0% of the air saturation value (ASV) throughout the test duration. Hence, the test was considered to be valid.

During the test, the measured concentrations of the test substance were below the limit of detection (LOD, LOD=0.505mg/L) by gas chromatograph (GC) method. There was no acute toxicity of the saturated solution in the limit test.

The 96h LC50 of the test substance to Gobiocypris rarus was higher than the concentration of the saturated solution (the measured concentration was below the LOD, LOD=0.505mg/L) under the tested conditions.

Description of key information

The 96h LC50 of the test substance to Gobiocypris rarus was higher than the concentration of the saturated solution (100 mg/L nominal; the measured concentration was below the LOD, LOD=0.505mg/L) under the tested conditions.