4'-Butyl-4-ethoxy-2,3-difluoro-1,1'-biphenyl

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 15, 2012 to Sep 10, 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: METI Guideline: Concentration Test on Chemical Substances in Fish

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 (Bioconcentration: Flow-through Fish Test)

Deviations:

no

Principles of method if other than guideline:

SPAN 20 used as solubilizer

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms during uptake phase: days 0, 7, 14, 21, 26, 28
- Sampling intervals/frequency for test medium samples during uptake phase: days 0, 7, 14, 21, 23, 28
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):
Water: Extraction with CH2Cl2 with further HPLC analysis.
Fish: two fish per sampling homogenised, and extracted with acetonitril/n-hexane. The analysis was performed using HPLC.

- Sampling intervals/frequency for test organisms and test medium during Depuration phase: sampling days 2, 6, 9, 14, 21

Vehicle:

yes

Details on preparation of test solutions, spiked fish food or sediment:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Tween 80
- Concentration of vehicle in test medium (stock solution and final test solution(s) at different concentrations and in control(s)): 0.08 and 0.008 mg/l
Dose 1: Test item: 0.02 mg/L , Vehicle: 0.08 mg/L
Dose 2: Test item: 0.002 mg/L , Vehicle: 0.008 mg/L
Vehicle Control: test item: - , Vehicle: 0.08 mg/L

Test organisms (species):

Cyprinus carpio

Details on test organisms:

Common carp Cyprinus carpio (Lot No. 120316)
Supplier: Commercial Breeding Farm (Japan)
Dates purchased Mar 16, 2012
Feeding and acclimatization:
After receiving the fish at the Institute of Ecotoxicology Co., Ltd., those with a total length of approx. 6.7 ± 0.2 cm were selected.
Mean bodyweight 2.88 ± 0.35 g
Mean total length 6.7 ± 0.2 cm
Mortality of fish during the experiment
High exposure level 0%
Low exposure level 0%
Control 0%

Lipid contents (by chloroform/methanol extraction method)
Before experiment 4.8% (Mean value, n=2)
After experiment 4.2 % (Mean value, n=2)

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

28 d

Total depuration duration:

21 d

Test temperature:

26.5 ° +/- 0.2 °C

pH:

7.7 +/- 0.1

Dissolved oxygen:

DO oftest water: 7.23 ± 0.2 mg/L

Salinity:

According to guideline

Details on test conditions:

After acclimatisation period, the fish (Cyprinus carpio) were transferred into the test media under flow through conditions. Exposure concentrations were analytically verified at days 0, 7, 14, 21, 23 and 28. The analytical values at nominal concentrations of 0.04 and 0.004 mg/L were maintained at about 100% using solubiliser, respectively. At days 0, 7, 14, 21, 23 and 28 two fish each were removed from each test group. Body weight was determined. The fish were homogenised and extracted using organic solvents. The extract was analysed with HPLC. Due to the high bioaccumulation potential, a depuration phase was required. Depuration was followed for 21 days.

Nominal and measured concentrations:

nominal concentration 0.02 mg/L:
analytically measured concentrations:

day 0: 0.0192 mg/L
day 7: 0.0174 mg/L
day 14: 0.0191 mg/L
day 21: 0.0201 mg/L
day 26: 0.0196 mg/L
day 28: 0.0211 mg/L


nominal concentration 0.002 mg/L
analytically measured concentrations:

day 0: 0.00187 mg/L
day 7: 0.00166 mg/L
day 14: 0.00183 mg/L
day 21: 0.00206 mg/L
day 26: 0.00210 mg/L
day 28: 0.00216 mg/L

Details on estimation of bioconcentration:

according to guideline

Conc. / dose:

0.02 mg/L

Temp.:

26 °C

pH:

7.7

Type:

BCF

Value:

3 212 dimensionless

Basis:

normalised lipid fraction

Time of plateau:

14 d

Calculation basis:

steady state

Conc. / dose:

0.002 mg/L

Temp.:

26.6 °C

pH:

7.7

Type:

BCF

Value:

2 948 dimensionless

Basis:

not specified

Time of plateau:

14 d

Calculation basis:

steady state

Elimination:

yes

Parameter:

DT50

Depuration time (DT):

6.4 d

Rate constant:

overall depuration rate constant (d-1)

Value:

0.122

Details on kinetic parameters:

Steady state was reached within 14 days
Depuration phase was necessary.

Details on results:

- Mortality of test organisms: no effects
- Behavioural abnormalities:no effects
- Observations on body length and weight:no effects
- Other biological observations: no effects
- Bound residues forming a plateau: no
- Mortality and/or behavioural abnormalities of control: no
- Loss of test substance during test period: no
- Results with vehicle control: no effects

Validity criteria fulfilled:

yes

Conclusions:

The test material showed a significant bioconcentration potential with a mean BCFss of 3077.

Executive summary:

The purpose of this study was to determine the bioconcentration potential of the test material in fish under flow-through conditions.The test was performed for registration in Asia.

The study was performed according to the OECD Guideline for Testing of Chemicals 305 (Bioconcentration: Flow-through Fish Test) adopted on June 14, 1996 using two test material concentrations for exposure to Cyprinus carpio. Two environmental concentrations of the test material of 0.02 and 0.002 mg/L were used in this study. Tween 80 was used as vehicle at concentrations of 0.08 and 0.008 mg/L. The exposure was maintained during the couse of the study at about 100% of the nominal concentrations. The concentrations have been verified analytically using a HPLC method with UV detection.
After the accumulation, a depuration phase was performed.

No signs of toxicity were observed throughout the study. The analysis reveals steady state BCFs of 3212 and 2948 (mean: 3077). Due to the bioaccumulation potential, a depuration phase was required. In the depuration phase the observed concentrations in fish decreased over time and a DT50 of 6.4 days and a rate constant of 0.122 were calculated.
The test material showed a significant bioconcentration potential with a mean BCFss of 3077.

Description of key information

The analysis reveals steady state BCFs of 3212 and 2948 (mean: 3077).

Key value for chemical safety assessment

BCF (aquatic species):

3 077 dimensionless