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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:
2004-06-28 to 2004-08-31
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Reliable GLP study in accordance with guideline
Qualifier:
according to
Guideline:
OECD Guideline 305 (Bioconcentration: Flow-through Fish Test)
Deviations:
no
GLP compliance:
yes
Radiolabelling:
no
Details on sampling:
- Sampling intervals/frequency for test organisms: Analyses of the test item in the test fish were performed 5 times during the exposure period, measuring for both concentration levels 1 and 2, with 4 samples each, divided into 2 groups (2 in each group) (*2) per analysis. Analyses of the test item in the control fish were performed before the start and after the end of the experiment, with 4 samples divided into 2 groups (2 in each group) per analysis. In addition, 2 samples were obtained for lipid measurements. The analyses were performed on each of the 3 groups (2 in each group).
(*2): A group consisting of 2 fish was used since a single fish could not provide sufficient sample to be preserved for lipid measurement.
- Sampling intervals/frequency for test medium samples: During the exposure period, analyses of the test item in the test water were performed once before the same analysis was performed in the test fish; subsequently, analyses of the test item in the test water were performed concurrently with the analyses in the test fish, with one sample each per analysis.
- Sample storage conditions before analysis: no storage before analysis
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods): see attached document






Vehicle:
not specified
Details on preparation of test solutions, spiked fish food or sediment:
PREPARATION OF SPIKED WATER

- Details of spiking:
Preparation of stock solution: Dispersants 2-Methoxyethanol and HCO-40
Preparation method:
Concentration level 1: The test item and a 20-fold HCO-40 were dissolved into 2-methoxyethanol to prepare a 10 g/L stock solution. A 200-mg/L stock solution was prepared.
Concentration level 2: The test item and a 20-fold HCO-40 were dissolved into 2-methoxyethanol to prepare a 10 g/L stock solution. A 20-mg/L stock solution was prepared.
Test concentrations:
Test concentrations were set as follows by considering the 96-hour LC50 value and the analytical sensitivity of the test item obtained in the preliminary study:
Concentration level 1: 5 µg/L (1% of acute LC50 - according to guideline)
Concentration level 2: 0.5 µg/L
Negative control was also set up.

- Controls: HCO-40 was dissolved in 2-methoxyethanol to prepare a 4 g/L stock solution.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): 2-Methoxyethanol and HCO-40 (INCI name: PEG-40 Hydrogenated Castor Oil)
- Concentration of vehicle in final test solution: 0.05 mL/L
Test organisms (species):
Cyprinus sp.
Details on test organisms:
TEST ORGANISM
- Common name: carp
- Strain: Lot number TFC-031222-V
- Source: Kurume Laboratory, Chemicals Evaluation and Research Institutes
- Age at study initiation (mean and range, SD): Yearling fish
- Length at study initiation (lenght definition, mean, range and SD): 7.5-9.2 cm
- Weight at study initiation (mean and range, SD):
- Weight at termination (mean and range, SD):
- Method of breeding: no data
- Health status: according to study report "abnormal fish were removed" during acclimatisation
- Feeding during test
- Food type: Juvenile carp mixed food
- Amount and frequency: Fish were fed twice daily at a total rate of approximately 2% of their body weight per day (fed once a day on holiday). Feeding was stopped the day before the sampling.

ACCLIMATION
- Acclimation period and conditions (same as test or not): Hatched juvenile fish were cultured in an appropriate tank until they were fully grown and were suitable for use in the study. Fish were then transferred to an acclimatization tank and treated with a medicated bath. These fish were subsequently acclimatized for 29 days at 25 ± 2ºC under flow-through conditions. During this period, abnormal fish were removed. The remaining fish were transferred to the test tank and treated with another medicated bath. These fish were acclimatized for another 19 days at the same temperature as above, under flow-through conditions.
Medicated bath: Fish were treated with a medicated bath containing 20 mg/L Erubaju and 7 g/L sodium chloride for 24 hours in the acclimatization tank.
These fish were also treated with a medicated bath containing 20 mg/L Erubaju and 7 g/L sodium chloride for 24 hours in the test tank.
- Health during acclimation (any mortality observed): according to study report "abnormal fish were removed" during acclimatisation
Route of exposure:
aqueous
Test type:
flow-through
Water / sediment media type:
natural water: freshwater
Total exposure / uptake duration:
28 d
Hardness:
90.1 mg/L
Test temperature:
Concentration level 1: 24.9-25.3ºC
Concentration level 2: 24.9-25.4ºC
Control: 24.9-25.3ºC
pH:
Concentration level 1: 7.5-7.6
Concentration level 2: 7.5-7.6
Control: 7.6-7.8
Dissolved oxygen:
Concentration level 1: 6.4-7.3 mg/L
Concentration level 2: 6.5-7.3 mg/L
Control: 7.6-8.1 mg/L
TOC:
no data
Salinity:
freshwater study, thus not relevant
Details on test conditions:
TEST SYSTEM
- Test vessel, material, size, fill volume: 100-L glass tanks for volatile tests
- Type (delete if not applicable): closed
- Aeration: supply of oxygen via flow-through of fresh test water
- Type of flow-through (e.g. peristaltic or proportional diluter): proportional diluter
- Renewal rate of test solution (frequency/flow rate): rate of 1728 L/day
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control / vehicle control (replicates): 1
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Ground water pumped on the premise of the CERI Kurume.
- Particulate matter: not of relevance as ground water was used
- Metals: detailed analytical data on toxic metals are given in the study report (no unusual findings)
- Pesticides: detailed analytical data are given in the study report (no unusual findings)
- Chlorine: not of relevance as ground water was used
- Alkalinity: 124 mg/L
- Ca/Mg ratio: no data
- Conductance: 431 microS/cm
- Holding medium different from test medium: no
- Intervals of water quality measurement:
Test water volume: Test water volume was measured and recorded using a measuring cylinder once a day.
Test temperature: Test temperature was measured and recorded using an alcohol thermometer once a day.
Dissolved oxygen concentrations: Dissolved oxygen concentrations were measured and recorded using a dissolved oxygen meter twice a week.
pH: pH values were measured and recorded using a pH meter at least once a week.
- Intervals of test medium replacement: The stock solution (0.03 mL/min) and the test water (1200 mL/min) were mixed and added to the test tank at a rate of 1728 L/day.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 14-hour light/10-hour dark
- Light intensity: Artificial lighting with white fluorescent lamps

RANGE-FINDING / PRELIMINARY STUDY
- Test concentrations: 0.125, 0.25, 0.5, 1.0, and 2.0 mg/L
- Results used to determine the conditions for the definitive study: acute fish toxicity study with resulting LC50 = 0.77 mg/L
Nominal and measured concentrations:
Concentration level 1 (µg/L): day 3 4.48, day 6 4.61, day 9 4.52, day 14 4.63, day 21 4.46, day 28 4.52
Concentration level 2 (µg/L): day 3 0.456, day 6 0.46, day 9 0.45, day 14 0.455, day 21 0.461, day 28 0.449
Reference substance (positive control):
not specified
Details on estimation of bioconcentration:
not applicable
Lipid content:
3.26 %
Time point:
start of exposure
Lipid content:
3.84 %
Time point:
end of exposure
Type:
BCF
Value:
530 dimensionless
Basis:
whole body w.w.
Time of plateau:
28 d
Calculation basis:
steady state
Remarks on result:
other: Conc.in environment / dose:5 µg/L
Type:
BCF
Value:
690 dimensionless
Basis:
whole body w.w.
Time of plateau:
28 d
Calculation basis:
steady state
Remarks on result:
other: Normalised to 5% lipid content
Remarks:
Conc.in environment / dose:5 µg/L
Type:
BCF
Value:
560 dimensionless
Basis:
whole body w.w.
Time of plateau:
28 d
Calculation basis:
steady state
Remarks on result:
other: Conc.in environment / dose:0.5 µg/L
Type:
BCF
Value:
729 dimensionless
Basis:
whole body w.w.
Time of plateau:
28 d
Calculation basis:
steady state
Remarks on result:
other: Normalised to 5% lipid content
Remarks:
Conc.in environment / dose:0.5 µg/L
Details on kinetic parameters:
none reported
Metabolites:
none reported
Results with reference substance (positive control):
no reference substance used
Details on results:
- no unusual observations reported
Validity criteria fulfilled:
yes
Conclusions:
The bioconcentration factor of the substance in fish was determined in a flow-through system to range from 530 to 560 (dimensionless BCF). Normalised to 5% lipid content the BCFs are 690 and 729, respectively.
Executive summary:

The purpose of this study was to determine the bioconcentration potential of test item in carp. Therefore a valid and reliable study according to OECD 305 was conducted. A flow-through design was applied. An uptake phase was studied over 28 days. A steady state was achieved after 14 days (variation of BCFs on day 14, 21, 28 < 20%). No depuration phase was studied, but as a steady-state was reached during the uptake phase, the missing BCFk does not lower the reliability of the study and the BCFk should be in the same range as the BCFss.

As the substance has a low water solubility (around 1 mg/L) the dispersant HCO-40 was used for preparation of stock solutions of 200 and 20 mg/L. Even though the use of a dispersant is not recommended in the guideline, HCO-40 is mentioned in the 1996 guideline as dispersant which may be used. Yakata et al. (2006) showed that BCF results are not adversely affected by dispersants, if tested below the water solubility. The two tested concentrations of 5.0 and 0.5 µg/L are clearly below the water solubilty. Thus, despite the use of the dispersant the results of the study are reliable.

The determined BCFs are 530 to 560 and normalised to 5% lipid content 690 and 729, respectively.

Description of key information

The substance is considered to be not bioaccumulative on the basis of reliable and valid experimental data.

Key value for chemical safety assessment

BCF (aquatic species):
560 dimensionless

Additional information

The bioconcentration factor of the substance (ethoxymethoxy)cyclododecane was determined experimentally under GLP in accordance with OECD TG 305. The study was conducted with common carp (Cyprinus carpio) in a flow through system applying experimental conditions in accordance with the guideline. The bioconcentration factor ranged from 530 to 560 (690 - 729 normalised to 5% lipid content) demonstrating that the substance should not be considered as bioaccumulative in accordance with the criteria set out in the REACH Regulation.