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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Reference
Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19-5-2000 - 23-11-2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 305 (Bioconcentration: Flow-through Fish Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Radiolabelling:
yes
Details on sampling:
- Sampling intervals/frequency for test organisms: after 1, 2, 6, 7, and 8 days of exposure and each day during elimination
- Sampling intervals/frequency for test medium samples: daily during exposure starting 2 days prior to exposure
- Sample storage conditions before analysis: Not relevant, samples were analysed immediately
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods): The water samples (2 mL) were measured on the dayof the sampling. The fish sampled were rinsed quickly with untreated water, blotted dry and then instantly killed. Subsequently, fish were weighed. The fish were pooled in two samples of two fish. A homogenate was prepared of each of the pooled samples by dissolving the samples in Soluene 350. After the samples had been completely dissolved, a part of the homogenate was weighed and used to determine the bioconcentration in the wholefish. Then 100 mL of H2O2 (35%) was added to each sample to bleach them during a period of at least 2 hours before the scintillation liquid was added.
Vehicle:
yes
Details on preparation of test solutions, spiked fish food or sediment:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The stock solutions were individually prepared in a mixture of ethanol at a factor 10000 higher than the final test concentration. Both stock solutions contained 7 mg/L 14C-Iabelled 2-Ethylhexyl 4-methoxycinnamate.
- Controls: Test medium without test substance but with ethanol at 100 mg/L.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): ethanol
- Concentration of vehicle in test medium (stock solution and final test solution(s) at different concentrations and in control(s)): 0.1 mL/L
- Evidence of undissolved material: no
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
TEST ORGANISM
- Common name: Rainbow trout
- Source: Blo International, Horn, The Netherlands
- Length at study initiation (lenght definition, mean, range and SD): 4.9 ± 0.14 cm (n = 60)
- Weight at study initiation (mean and range, SD): 1.94 ± 0.21 g (n = 60)
- Weight at termination (mean and range, SD): no data, the possible increase of weight is considered irrelevant (short study period)
- Health status: Healthy fish supplied with a health certificate
- Feeding during test
- Food type: Trouvit.
- Amount: Ca. i % of bodyweight per day of Feeding rate was recalculated after every time fish had been sampled during the uptake phase.
- Frequency: daily

ACCLIMATION
- Acclimation period: At least 12 days after delivery. The fish were allowed to acclimatize to the test conditions without test substance for seven days prior to testing.
- Acclimation conditions (same as test or not): yes
- Type and amount of food: Trouvit
- Feeding frequency: Daily
Route of exposure:
aqueous
Test type:
flow-through
Water / sediment media type:
natural water: freshwater
Total exposure / uptake duration:
5 d
Total depuration duration:
9 d
Hardness:
200 - 220 mg CaCO3/L
Test temperature:
control 15.5 ± 0.7, low exposure 15.2 ± 0.7, high exposure 15.3 ± 0.7
pH:
7.8 - 7.9
Dissolved oxygen:
group Day of measurement
0 2 5 12 14
Respectively at day 0, 2, 5, 12 and 14: Control 9.1 6.9 6.4-9.0 8.8 8.2
Lowerlevel 9.0 6.8 6.6-9.0 8.9 8.4
Higher level 9.1 6.8 6.7-9.0 9.1 8.6
TOC:
In none of the samples taken from the dilution water, the total concentration of organic carbon exceeded
10mg/I.
Salinity:
not relevant
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 litres (50x50x40 cm) consisting of stainless steel and covered by a removable Perspex plate.
- Type: closed
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): via a computer-controlled system consisting of micro-dispensers
- Renewal rate of test solution (frequency/flow rate): 12 L/h
- No. of organisms per vessel: 40
- No. of vessels per concentration (replicates): 1
- No. of vessels per control / vehicle control (replicates): 1
- Biomass loading rate: 0.3 g fish.litre-1.day-1.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water
- Intervals of water quality measurement: pH, nitrate and nitrite concentration and ammonia concentration: once a week. Temperature: every day

OTHER TEST CONDITIONS
- Photoperiod:16 hours photoperiod daily

RANGE-FINDING / PRELIMINARY STUDY
- Test concentrations:
- Results used to determine the conditions for the definitive study:

TEST SYSTEM
- Test vessel: 100 litres (50x50x40 cm) consisting of stainless steel and covered by a removable Perspex plate.
- Type: closed
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): via a computer-controlled system consisting of micro-dispensers
- Renewal rate of test solution (frequency/flow rate): 12 L/h
- No. of organisms per vessel: 40
- No. of vessels per concentration (replicates): 1
- No. of vessels per control / vehicle control (replicates): 1
- Biomass loading rate: 0.3 g fish.litre-1.day-1.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water
- Conductance: 15 °DH, corresponds with 260 - 270 mg CaCO3/L.
- Intervals of water quality measurement: Dissolved oxygen content and pH: two times during the five-day uptake period, at the start and once a week during the depuration period; temperature: daily; Total hardness and conductivity: At the start and the end of the test period

OTHER TEST CONDITIONS
- Photoperiod: 16 hours photoperiod daily
Nominal and measured concentrations:
nominal: 0, 70 and 700 µg/L
71.8 - 89.3 µg/L (time weighed average 84 ± 6.7 µg/L), 731, 789 µg/L (time weighed average 731 ± 22 µg/L)
Reference substance (positive control):
no
Details on estimation of bioconcentration:
not relevant, bioconcentration is measured
Remarks on result:
not measured/tested
Key result
Conc. / dose:
ca. 70 µg/L
Type:
BCF
Value:
433 L/kg
Basis:
whole body w.w.
Time of plateau:
0.92 d
Calculation basis:
steady state
Remarks on result:
other: Upper limit, range 279 - 433
Key result
Conc. / dose:
ca. 700 µg/L
Type:
BCF
Value:
175 L/kg
Basis:
whole body w.w.
Time of plateau:
2.25 d
Calculation basis:
steady state
Remarks on result:
other: upper limit, range 64 - 175
Key result
Elimination:
yes
Parameter:
DT50
Depuration time (DT):
1.7 d
Elimination:
yes
Parameter:
DT90
Depuration time (DT):
5.5 d
Details on kinetic parameters:
- Uptake rate constant (k1): no
- Depuration (loss) rate constant (k2): -0.4184 for the low concentration and -0.4572 for the high concentration.
- Indication of bi- or multiphasic kinetics: yes
Metabolites:
no data
Details on results:
- Behavioural abnormalities: no
- Observations on body length and weight: considered not significant
- Mortality and/or behavioural abnormalities of control: no
- Results with vehicle control: no abnormalities

During the first 1.24 days, the concentration of Ethylhexyl Methoxycinnamate in the fish exposed to 70 µg/L increased to 32 µg/g fish, while the concentration in the fish exposed to 700 µg/L increased to 49 µg/g. The concentration in the fish exposed to 70 µg/L varied between 25 and 36 µg/g during the remaining period of the uptake phase.

The BCF remained rather constant between 279 and 433 with an average of 373. Until day 5, the concentration in the fish exposed to 700 µg/L only slowly increased after the first day until 2.25 days. The BCF remained constant at 64 - 72. However, on the last day the concentration in the fish had increased by more than a factor of two resulting in a final BCF of 175.

Validity criteria fulfilled:
yes
Conclusions:
At the lower exposure level the BCF was 433 and at the higher level the BCF was 175. Depuration (DT50) of Ethylhexyl Methoxycinnamate out of the fish was 1.5 to 1.7 days.
Executive summary:

A l4 days Bioconcentration test in rainbow trout with 2-Ethylhexyl 4-methoxycinnamate and radiolabelled Ethylhexyl Methoxycinnamate was conducted according to the OECD guidelines for Testing of Chemicals, guideline No. 305: Bioconcentration: Flow-through Fish Test. During the first 1.24 days, the concentration of Ethylhexyl Methoxycinnamate in the fish exposed to the lower level of Ethylhexyl Methoxycinnamate increased to 32 µg/g fish, while the concentration in the fish exposed to the higher level increased to 49 µg/g. At the lower level the BCF remained rather constant between 279 and 433 with an average of 373. At the higher level, the concentration in the fish only slowly increased after the first day until 2.25 days and the BCF remained below 100 (64 - 76). However, on the last day the concentration in the fish had increased by more than a factor of two resulting in a final BCF of 175. Depuration of Ethylhexyl Methoxycinnamate out of the fish was exponential with a DT50 of 1.5 to 1.7 days and a DT 90 of 5.0 to 5.5 days.

Description of key information

Bioconcentration factor: 279 - 433 at test concentration 70 µg/L, 64 - 175 at test concentration 700 µg/L (OECD TG 305)

Key value for chemical safety assessment

BCF (aquatic species):
433 L/kg ww

Additional information

The 14-day Bioconcentration test in rainbow trout was performed with radiolabelled Ethylhexyl Methoxycinnamate. During the first day, the concentration in the fish exposed to the lowest level (70 µg/L) increased to 32 µg/g fish, while the concentration in the fish exposed to the higher level (700 µg/L) increased to 49 µg/g. At the lower level the BCF remained rather constant between 279 and 433 with an average of 373. At the higher level, the concentration in the fish only slowly increased until day 2 and the BCF remained below 100 (64 - 76). However, on the last day the concentration in the fish had increased by more than a factor of two resulting in a final BCF of 175. Depuration of Ethylhexyl Methoxycinnamate out of the fish was exponential with a DT50 of 1.5 to 1.7 days and a DT90 of 5.0 to 5.5 days.