4'-Ethyl-2,3-difluorbiphenyl-4-boronic acid

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:

31 Oct 2018 - Jan 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The samples were taken from the biological phase of the study. Collecting, storage and handing over of the samples were the Study Director’s responsibility. The information concerning the samples was provided by the Study Director.
One sample of the freshly prepared stock solution filtrate and duplicate samples from the freshly prepared test media of the only test concentration and the control were taken at the start of the test and at each test medium renewal (on day 1, 2 and 3).
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentration during the test period, duplicate samples from the aged test media of the only test concentration and the control were collected at each test medium renewal (on day 1, 2 and 3) and the end of the test (after 96 hours) from the approximate centre of the aquaria.
The samples were diluted by a factor of two with acetonitrile.
Additional samples of the control and of the dilution solvent were taken at each sampling without any sample treatment.

Vehicle:

no

Details on test solutions:

Reconstituted Water
(ISO Medium):
In deionised water (conductivity <= 10 µScm-1) analytical grade salts were added to following nominal concentrations:
CaCl2 x 2H2O : 2.0 mmol/L (= 294.0 mg/L)
MgSO4 x 7H2O : 0.5 mmol/L (= 123.0 mg/L)
NaHCO3 : 0.75 mmol/L (= 65.0 mg/L)
KCl : 0.075 mmol/L (= 5.8 mg/L)

Water Hardness : 2.5 mmol/L (= 250.0 mg/L) as CaCO3
Alkalinity : 0.8 mmol/L
Ratio of Ca : Mg = 4 : 1 (based on molarity)
Na : K = 10 : 1 (based on molarity)

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Strain: Oncorhynchus mykiss
- Source: Forellenzuchtbetrieb Störk, 88348 Bad Saulgau, Germany
- Age at study initiation (mean and range, SD): juvenile
- Length at study initiation (length definition, mean, range and SD): 4.75 +/- 0.5 cm
- Weight at study initiation (mean and range, SD): 1.20 +/- 0.40 g
- Method of breeding: laboratory standard
- Maintenance of the brood fish: 12 days under test conditions

ACCLIMATION
- Acclimation period: 12 days
- Acclimation conditions (same as test or not): same
- Type and amount of food during acclimation:
- Feeding frequency during acclimation: three times per week or daily until 24 hours before the test was started
- Health during acclimation (any mortality observed): no


FEEDING DURING TEST
- Food type: --
- Amount: --
- Frequency: --

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

250 mg/L

Test temperature:

13.8 to 14.7 °C

pH:

7.4 - 7.9

Dissolved oxygen:

92 to 101 %

Nominal and measured concentrations:

The lowest EC50 value of existing relevant algae or acute invertebrate (e.g. daphnia) tests was set as threshold concentration. This threshold approach was performed in order to demonstrate that the test item has no toxic effects on the test fish up to the threshold concentration or at 100 mg (test item)/L.
Due to the low limit of water solubility of the test item, a filtrate of nominal 100 mg/L was prepared. From this stock solution, a nominal test concentration of 0.045 mg test item/L and a control were prepared.
The dilution of this filtrate corresponds to following geometric mean measured concentrations of the test item:
0.0241 mg test item/L and a control.

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.045 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.045 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.024 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no
- Observations on body length and weight:no
- Other biological observations: no
- Mortality of control: no
- Other adverse effects control: no
- Abnormal responses: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Sublethal observations / clinical signs:

Observed Mortality of unfed Rainbow Trout (Oncorhynchus mykiss) exposed to the test item filtrate for 96 hours

Nominal Loading Rate / [mg/L]	Mortality
	0 h	2 h	24 h	48 h	72 h	96 h
Control	0	0	0	0	0	0
0.0241	0	0	0	0	0	0
LC50 / [mg/L]	> 0.0241	> 0.0241	> 0.0241	> 0.0241	> 0.0241	> 0.0241
95 % Cl	n.d.	n.d.	n.d.	n.d.	n.d.	n.d.

Nominal loading rate: 0.045 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The toxic effect of the test item to Rainbow Trout (Oncorhynchus mykiss) was assessed in a semi-static concentration-response test. Based on the test results the 96-hour LC50 was determined to be > 0.0241 mg test item/L which corresponds to 0.045 mg/L nominal loading rate.

Description of key information

GLP compliant OECD 203 Study: EC50 > 0.0241 mg/L (nominal threshold concentration of 0.045 mg/L as defined by lowest effect observed in daphnia and algae)