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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Please refer to the category approach justification provided in section 13.
Reason / purpose:
read-across source
Type:
BCF
Value:
387.5 L/kg
Basis:
not specified
Time of plateau:
24 h
Calculation basis:
steady state
Remarks on result:
other: Conc.in environment / dose:0.033 µM steady state concentration of the test compound in water
Remarks:
Source, key, Alcohol ethoxylates (C16EO8), Tolls et al., 2000, fish, 72 h, RL2
Conclusions:
The reported BCF value is 387.5 L/kg.
Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well documented publication which meets basic scientific principles
Qualifier:
no guideline followed
Principles of method if other than guideline:
Fish were exposed in a flow-through system to the test substance during an uptake phase of up to 72 h. The following elimination phase lasted for 24 h.
GLP compliance:
no
Radiolabelling:
no
Vehicle:
no
Test organisms (species):
Pimephales promelas
Details on test organisms:
TEST ORGANISM
- Common name: fathead minnow
- Source: hatchery of Utrecht University, The Netherlands
- Weight at study initiation (mean and range, SD): 0.5 - 1.0 g

ACCLIMATION
- Acclimation period: at least 1 week
- Type and amount of food: Lapis dry feed at a rate of 1% of body weight
- Feeding frequency: daily
Route of exposure:
aqueous
Test type:
flow-through
Water / sediment media type:
natural water: freshwater
Total exposure / uptake duration:
54 - 72 h
Total depuration duration:
24 h
Test temperature:
20.7 - 22.5 °C
Details on test conditions:
TEST SYSTEM
- Test vessel: 5 - 8 L aquaria
- No. of organisms per vessel: 30


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted freshwater was prepared by dissolving 0.75 mM CaCl2 x 2H2O, 0.46 mM MgSO4 x 7H2O, 1.51 mM NaHCO3, 0.04 mM KH2PO4, 1.01 mM NaNO3 and 0.10 mM Na2SiO3 in distilled water.

Nominal and measured concentrations:
The AE concentrations were higher than the critical micelle concentration. 0.029 µM steady state concentration of the test compound in water
Reference substance (positive control):
no
Lipid content:
0.9 - 8.2 %
Time point:
start of exposure
Remarks on result:
other: average content: 4.9%
Type:
BCF
Value:
387.5 L/kg
Basis:
not specified
Time of plateau:
24 h
Calculation basis:
steady state
Remarks on result:
other: for C16EO8
Remarks:
Conc.in environment / dose:0.033 µM steady state concentration of the test compound in water
Details on results:
- Mortality of test organisms: no mortality was observed
- Behavioural abnormalities: no signs of sublethal effects, such as swimming or breathing behavior, were observed during the experiments.

The test substance was not stored inside fish and no relationship between BCF and lipid content was observed. The elimination rate suggested rapid biotransformation of the test substance.

Description of key information

Bioaccumulation in organisms is negligible, due to biotransformation and excretion of alcohol ethoxylates.

Key value for chemical safety assessment

Additional information

In a publication on the bioconcentration of alkylethoxylates Tolls et al. (2000) reported BCF-values ranging from <5 to 387.5 whereas uptake rates varied from 330 to 1660 (L x kg/d) and elimination rates varied from 3.3 to 59 per day. The authors stated that the time of steady state and the BCF for AE increase with increasing chain length of alkyl chain and decreasing length of the ethoxylate chain. The alcohol ethoxylate with alkyl-chain length comparable to the given substance is C16EO8. For this alcohol ethoxylate Tolls et al. (2000) reported a BCF-value of 387.5 L/kg.

The authors further concluded that the high values of elimination rate constants suggest that the tested fathead minnow efficiently biotransform alcohol ethoxylate, thereby preventing them from attaining high concentrations in fish.