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Bioaccumulation: aquatic / sediment

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Endpoint:
bioaccumulation in aquatic species: fish
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance has a low potential for bioaccumulation based on log Kow <=3
Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Old but reasonably well described study. Similar to present guidelines.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Determination of BCF after static exposure; followed by a period of depuration in fresh water.
GLP compliance:
not specified
Radiolabelling:
yes
Details on sampling:
- Sampling intervals/frequency for test medium samples: During the uptake experiment: groups of 5 fish, sampling at 8, 24, 48 and 96 h of exposure. During the depuration experiment: groups of 5 fish, sampling at 0, 8, 24, 48 and 72 h of depuration.
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods): All sacrificed fish were rinsed in fresh water, blotted and the wet weight determined. The gallbladder was removed. The viscera and the remaining carcass of each fish were weighed and solubilised separately.
Vehicle:
no
Details on preparation of test solutions, spiked fish food or sediment:
A stock solution of melamine in water was prepared.
Melamine concentration in test water: 10 050 cpm/mL; 0.083 mg/L. It remained nearly constant over the duration of the exposure and averaged 0.0082 mg/L during both experiments (uptake and uptake/elimination).
Test organisms (species):
Pimephales promelas
Details on test organisms:
Adult fathead minnows (Pimephales promelas) were obtained from a laboratory-raised stock of fish maintained by the University of Wisconsin-Milwaukee, Center for Great Lakes Studies, Milwaukee, WI.
Route of exposure:
aqueous
Test type:
static
Water / sediment media type:
natural water: freshwater
Total exposure / uptake duration:
96 h
Total depuration duration:
72 h
Test temperature:
20.1 (20.0-20.4) (Exposure phase)
20.2 (19.8-20.4) (Depuration phase)
pH:
7.0 ± 0.23 (Exposure phase)
Dissolved oxygen:
D.O. (mg/L): 7.9 ± 0.14 (Exposure phase)
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 11.4 L glass battery jars filled to 10 L.
- Aeration: gentle aeration from a single air-stone
- Renewal rate of test solution (frequency/flow rate): not applicable
- No. of organisms per vessel: 25
- No. of vessels per concentration (replicates): 2 (one vessel for uptake, one vessel for uptake/elimination)
- No. of vessels per control / vehicle control (replicates): No control group

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: mixed hot and cold dechlorinated tap water

OTHER TEST CONDITIONS
- Photoperiod: 12 h light, 12 h dark



Nominal and measured concentrations:
Total [14C]melamine concentration: nominal: 0.083 mg/L; actual mean: 0.082 mg/L.
Reference substance (positive control):
no
Details on estimation of bioconcentration:
BCF was calculated by dividing the mean tissue concentration at steady state (96 h of exposure) by the mean concentration of the test water over the entire exposure period. The kinetics constant k and t1/2 were calculated for each tissue with the use of a computer program.
Type:
BCF
Value:
0.48
Basis:
other: viscera
Time of plateau:
96 h
Calculation basis:
steady state
Remarks on result:
other: Uptake experiment
Remarks:
Conc.in environment / dose:0.082 mg/L
Type:
BCF
Value:
0.26
Basis:
other: carcass
Time of plateau:
96 h
Calculation basis:
steady state
Remarks on result:
other: Uptake experiment
Remarks:
Conc.in environment / dose:0.082 mg/L
Type:
BCF
Value:
0.32
Basis:
other: viscera
Time of plateau:
96 h
Calculation basis:
steady state
Remarks on result:
other: Uptake/elimination experiment
Remarks:
Conc.in environment / dose:0.082 mg/L
Type:
BCF
Value:
0.2
Basis:
other: carcass
Time of plateau:
96 h
Calculation basis:
steady state
Remarks on result:
other: Uptake/elimination experiment
Remarks:
Conc.in environment / dose:0.082 mg/L
Elimination:
yes
Parameter:
other: DT50 viscera
Depuration time (DT):
11.5 h
Elimination:
yes
Parameter:
other: DT50 muscle
Depuration time (DT):
14.84 h
Details on kinetic parameters:
Viscera: k = 0.0600; t1/2 = 11.50 h, calculated for 0-48 h depuration.
Muscle: k = 0.0465; t1/2 = 14.84 h, calculated for 0-48 h depuration.
A log plot of the tissue concentrations over time indicated that elimination of [14C]melamine was non-linear after 48 h of depuration.
The t1/2 values could not be calculated for the ß-phase since there was only one sampling period beyond 48 h.
Results with reference substance (positive control):
Not applicable
Details on results:
Uptake of [14C]melamine was relatively low (<50 ppb) and variable for both the viscera and carcass. The viscera data in particular, included several fish which exhibited tissue concentrations that were roughly two-fold higher than the median levels at each sampling interval. When individual viscera concentrations from the final uptake experiment are plotted along with data from several preliminary exposures, it appears that the levels for these "outliers" were abberrant; thus, they were edited from the data when calculating the mean tissue concentrations for the 96-h time course.
Steady state was reached at ca. 48 h.
Validity criteria fulfilled:
not specified
Executive summary:

The studies reported here describe the uptake, bioaccumulation and elimination of melamine (2,4,6 -triamino-1,3,5 -triazine) by the fathead minnow after static water exposure to [14C]melamine. Uptake of 14C was monitored until a steady state concentration of melamine was reached in the fish tissues and the bioconcentration factor (BCF) was determined. Static exposure to waterborne melamine was followed by a period of depuration in fresh flowing water to determine the time course of 14C-elimination from fish tissues.

The BCFs were below 1 for carcass and viscera. No indications for bioaccumulation were obtained. Depuration occurred with a half-life 11 to 14 h.

Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Old but reasonably well described study. Similar to present guidelines.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Determination of BCF after static exposure; followed by a period of depuration in fresh water.
GLP compliance:
not specified
Details on sampling:
- Sampling intervals/frequency for test medium samples: During uptake: groups of 5 fish, sampling at 16, 24, 48 and 96 h of exposure. During uptake-phase of uptake/elimination: exposure for 64 h, depuration-phase: groups of 5 fish, sampling at 8, 24, 48 and 72 h
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods): All sacrificed fish were rinsed in fresh water, blotted and the wet weight determined. The gallbladder was removed . The viscera and a skinless muscle fillet of each fish were weighed and solubilised separately.
Vehicle:
no
Details on preparation of test solutions, spiked fish food or sediment:
A stock solution of melamine in water was prepared.
Melamine concentration in test water for the uptake experiment: 10 050 cpm/mL; 0.083 mg/L; for the uptake/elimination experiment: 11 200 cpm/mL; 0.091 mg/L.
The concentration remained nearly constant over the duration of the exposure and averaged 0.0087 mg/L for the uptake experiment and 0.091 mg/L for the uptake/elimination experiment.
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
Fingerling rainbow trout (Salmo gairdneri) were obtained from Hideaway Springs Trout Farm, West Bend and maintained under laboratory conditions at the Medical College of Wisconsin until tests were performed.
Route of exposure:
aqueous
Test type:
static
Water / sediment media type:
natural water: freshwater
Total exposure / uptake duration:
72 h
Total depuration duration:
72 h
Test temperature:
13.9 (12.5-16.1) (Exposure phase)
14.0 (12.5-15.2) (Depuration phase)
pH:
7.59 ± 0.16 (Exposure phase)
Dissolved oxygen:
D.O. (mg/L): 9.70 ± 0.42 (Exposure phase)
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 11.4 glass battery jars filled to 10 L (Uptake) or larger vessels filled to 20 L (Uptake and Elimination)
- Aeration: gentle aeration from a single air-stone
- Renewal rate of test solution (frequency/flow rate): not applicable
- No. of organisms per vessel: 10 (Uptake), 20 (Uptake and Elimination)
- No. of vessels per concentration (replicates): 2 (Uptake), 20 (Uptake and Elimination)
- No. of vessels per control / vehicle control (replicates): No control group

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: mixed hot and cold dechlorinated tap water

OTHER TEST CONDITIONS
- Photoperiod: 12 h light, 12 h dark



Nominal and measured concentrations:
Total actual [14C]melamine concentration: 0.087 mg/L (Uptake).
Total actual [14C]melamine concentration: 0.091 mg/L (Uptake/elimination).
Reference substance (positive control):
no
Details on estimation of bioconcentration:
BCF was calculated by dividing the mean tissue concentration at steady state (96 h of exposure) by the mean concentration of the test water over the entire exposure period. The kinetics constant k and t1/2 were calculated for each tissue with the use of a computer program.
Type:
BCF
Value:
0.11
Basis:
other: viscera
Time of plateau:
72 h
Calculation basis:
steady state
Remarks on result:
other: Uptake experiment.
Remarks:
Conc.in environment / dose:0.089 mg/L
Type:
BCF
Value:
0.05
Basis:
other: muscle
Time of plateau:
72 h
Calculation basis:
steady state
Remarks on result:
other: Uptake experiment.
Remarks:
Conc.in environment / dose:0.089 mg/L
Type:
BCF
Value:
0.11
Basis:
other: viscera
Time of plateau:
64 h
Calculation basis:
steady state
Remarks on result:
other: Uptake/elimination experiment.
Remarks:
Conc.in environment / dose:0.091 mg/L
Type:
BCF
Value:
0.03
Basis:
other: muscle
Time of plateau:
64 h
Calculation basis:
steady state
Remarks on result:
other: Uptake/elimination experiment.
Remarks:
Conc.in environment / dose:0.091
Elimination:
yes
Parameter:
other: DT50 viscera
Depuration time (DT):
8.06 h
Elimination:
yes
Parameter:
other: DT50 muscle
Depuration time (DT):
6.79 h
Details on kinetic parameters:
Viscera: k = 0.0856; t1/2 = 8.06 h.
Muscle: k = 0.1015; t1/2 = 6.79h.
Results with reference substance (positive control):
Not applicable
Details on results:
Steady state was reached at ca. 48 h for viscera and ca. 16 h for muscle.
Uptake of [14C]melamine was relatively low (ca. 10 ppb).

Uptake of [14C]melamine over the 72 h time course was low for both body compartments, achieving levels only as high as 10 ppb. The [14C] levels for viscera reached steady state after 48 h of exposure, while muscle tissue levels appeared to reach saturation after only 16 h of exposure.

The low BCF´s for viscera and muscle indicated that waterborne melamine does not bioaccumulate readily in either the internal organs or flesh of rainbow trout. Following a 64-h exposure, melamine was rapidly eliminated from both body compartments within 72 h of depuration.

Validity criteria fulfilled:
not specified
Executive summary:

The studies reported here describe the uptake, bioaccumulation and elimination of melamine (2,4,6 -triamino-1,3,5 -triazine) by the rainbow trout after static water exposure to [14C]melamine. Uptake of 14C was monitored until a steady state concentration of melamine was reached in the fish tissues and the bioconcentration factor (BCF) was determined. Static exposure to waterborne melamine was followed by a period of depuration in fresh flowing water to determine the time course of 14C-elimination from fish tissues. Uptake of [14C]melamine over the 72 h time course was low for both body compartments (viscera and muscle), achieving levels only as high as 10 ppb. The [14C] levels for viscera reached steady state after 48 h of exposure, while muscle tissue levels appeared to reach saturation after only 16 h of exposure. Following a 64 h exposure, melamine was rapidly eliminated from both compartments within 72 h of depuration.

The BCFs were well below 1 for muscle and viscera. No indications for bioaccumulation were obtained. Depuration occurred with a half-life of 7 to 8 h.

Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Database source, only few details are provided, but data base is created and used by the Japanese authorities, and is therefore considered to be sufficiently reliable.
Principles of method if other than guideline:
Bioconcentration test
GLP compliance:
not specified
Remarks:
not specified
Test organisms (species):
Cyprinus carpio
Route of exposure:
aqueous
Test type:
flow-through
Total exposure / uptake duration:
6 wk
Nominal and measured concentrations:
2 mg/L and 0.2 mg/L.
Reference substance (positive control):
not specified
Type:
BCF
Value:
< 0.38 other: Conc.in environment / dose:2 ppm
Type:
BCF
Value:
< 3.8 other: Conc.in environment / dose:0.2 ppm
Executive summary:

Cyprinus carpio was exposed for 6 weeks to melamine at concentrations of 2 and 0.2 ppm. The bioconcentration factors are

BCF < 0.38 at 2 ppm.

BCF < 3.8 at 0.2 ppm.

Judgement: low bioconcentration.

Description of key information

The substance has a low potential for bioaccumulation.

Key value for chemical safety assessment

Additional information

Diphosphoric acid, compound with 1,3,5-triamine (1:2) has a low potential for bioaccumulation based on the experimentally determined log Pow of -1.24 at 20 °C (OECD 107).

Experimental data on the bioaccumulation of diphosphoric acid, compound with 1,3,5-triamine (1:2) are not available. Data available for the read-across substance melamine (CAS 108-78-1) report bioaccumulation factors < 1. The read across approach is in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. Further justification is given in the analogue justification in IUCLID section 13.