Dicyclohexylcarbodiimide

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May 24, 1985 - September 27, 1985.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

other: Bioaccumulation test of a chemical substance in fish or shellfish provided in "the Notice on the Test Method Concerning New Chemical Substances", Japan.

Version / remarks:

(1974, Order of the Prime Minister, the Minister of Health and Welfare, the MITI No. 1)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

GLP compliance:

not specified

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Solubility and stability of the test substance in the solvent/vehicle: water solubility 3.3 mg/L (by GC)

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: Analysis of test fish was conducted four times at 2, 3, 4 and 6 weeks after the start of breeding; analysis were performed immediately after collection in 2 replicates.
- Sampling intervals/frequency for test medium samples: Twice per week, analytical samples were collected from each of the test water tanks in the first and second concentration areas, pretreated, and quantitatively analyzed the test substances by a gas chromatograph (GC) method immediately after collection.
- Sample storage conditions before analysis: not applicable.
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):
- Pretreatment of water samples: chloroform extraction for GC analysis.
- Pretreatment of test organism samples: fish samples were crushed, treated with anhydrous sodium sulfate and chloroform and the filtrate was purified twice by column cromatographic method. The eluted fraction containing the test item was analysed by GC.

Vehicle:

yes

Remarks:

HCO-40 (polyoxyethylene hydrogenated castor Oil derivatives) and glacial sugar.

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

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 25 L of each stock solution were prepared twice daily.
- Chemical name of vehicle: crystal sugar, HCO-40 (polyoxyethylene hydrogenated castor Oil derivatives)
- Concentration of vehicle in test medium (stock solution and final test solution(s) at different concentrations and in control(s)):
- Stock solution: 500 mg/L test item in deionised water with 10 mg/L of crystal sugar and 50 mg/L of HCO-40.
- Test solution in the 1st concentration area: 1 mg/L
- Test solution in the 1st concentration area: 0.1 mg/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc): not specified.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: carp
- Strain: Cyprinus carpio
- Source: Yatsushiro City Kitamura Fish Farm, Kumamoto Prefecture, Lot No. TFC 850603
- Length at study initiation (length definition, mean, range and SD): 9.2 cm
- Weight at study initiation (mean and range, SD): 21.2 g
- Lipid content at test initiation (mean and range, SD): 4.3%
- Method of breeding: animals were bred in a 100L glass covered glass tank, in running water (582 L/day)
- Feeding during test
- Food type: carp diet (Nippon Shoku Foods Co. Ltd.)
- Amount: about 2% of the weight of the fish
- Frequency: twice per day

ACCLIMATION
- Acclimation period: 21 days at 25ºC
- Acclimation conditions: same as test.

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

6 wk

Total depuration duration:

0 wk

Test temperature:

25 ± 2 ºC

Dissolved oxygen:

First concentration zone: 5.9 – 7.0 mg/L
Second concentration zone: 6.0 – 7.9 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 L glass covered glass tank.
- Type (delete if not applicable): closed.
- Material, size, headspace, fill volume: glass, size 100 L.
- Renewal rate of test solution (frequency/flow rate): stock solution : dilution water = 4 ml/min : 400 ml/min (582 L/day of running water).
- No. of organisms per vessel: 15
- No. of vessels per concentration (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water was used as dilution water.
- Holding medium different from test medium: no.
- Intervals of test medium replacement: flow-through system.

RANGE-FINDING / PRELIMINARY STUDY
- Test concentrations: not specified.
- Results used to determine the conditions for the definitive study: A preliminary study of the 48h-TLm of the test item on Rice fish (Oryzias latipes) was performed according to method JIS K0102. The 48h-TLm of the test item on fish was found to be ≥ 250 mg/L.
- Measured logPow: logPow = 3.33 (measured according to OECD method)

Nominal and measured concentrations:

Nominal concentrations: 1 mg/L in 1st concentration area, 0.1 mg/L in 2nd concentration area.
Measured concentrations: 0.77-0.8 mg/L in 1st concentration area, 0.089-0.092 in 2nd concentration area (see 'Any other information on results').

Reference substance (positive control):

not required

Lipid content:

4.3 %

Time point:

start of exposure

Key result

Conc. / dose:

1 mg/L

Temp.:

25 °C

Type:

BCF

Value:

>= 0.2 - <= 0.7 L/kg

Basis:

not specified

Time of plateau:

3 wk

Calculation basis:

steady state

Remarks on result:

other: pH 6.0 - 8.5

Key result

Conc. / dose:

0.1 mg/L

Temp.:

25 °C

Type:

BCF

Value:

<= 2.2 L/kg

Basis:

not specified

Time of plateau:

6 wk

Calculation basis:

steady state

Remarks on result:

other: pH 6.0 - 8.5

Details on results:

- Mortality of test organisms: no.
- Behavioural abnormalities: not reported.
See any other details on results incl. tables.

	Bioaccumulation test results                          2 W 3 W 4 W 6 W 1st Concentration area Test substance concentration (mg/L) 0.776 0.806 0.809 0.802 Bioconcentration factor (L/kg) 0.3 0.5 0.4 <= 0.2 0.5 0.7 0.4 <= 0.2 2nd Concentration area Test substance concentration (mg/L)  0.0919 0.0915 0.0917 0.0894 Bioconcentration factor (L/kg) <= 2.2 <= 2.2 <= 2.2 <= 2.2 <= 2.2 <= 2.2 <= 2.2 <= 2.2

Validity criteria fulfilled:

yes

Remarks:

test parameters were maintained within guideline recommendations.

Conclusions:

Based on the study results, the BCF of the test item is lower than 2.2 L/kg in carp (worst case scenario).

Executive summary:

A bioaccumulation study of the test item in fish was performed according to Bioaccumulation test of a chemical substance in fish or shellfish (MITI No.1, 1974), equivalent to OECD 305C. Two levels of concentration as low as possible within the analytical limits (1 mg/L and 0.1 mg/L) were used, based on the results of the 48h-TLm determination of the test item in rice fish (Oryzias latipes), according to JIS K0102. The study was performed for 6 weeks on groups of Cyprinus carpio, along with periodical analytical determinations of the test item concentration in the tank water and in the test specimens by means of a validated analytical method. The BCF was determined at 2, 3, 4 and 6 weeks. In the 1 mg/L concentration level, a BCF of 0.7 L/kg was determined after 3 weeks, and a BCF lower than 0.2 L/kg at the end of the study. In the 0.1 mg/L concentration level, a BCF lower than 2.2 L/kg was determined at all time points. Based on the study results, the BCF of the test item is lower than 2.2 L/kg in carp (worst case scenario).

Reference 2

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:

REPORTING FORMAT FOR THE ANALOGUE APPROACH (see 'Attached justification')

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The analogue substance is the hydrolysis/transformation product of the target substance, and the substance is hydrolytically unstable at pH 4.00 and 7.00, so exposure to the analogue substance may be expected.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
- Source: N,N'-dicyclohexylurea, CAS No. 2387-23-7, purity 99.15%.
- Target: see 'test item'.

3. ANALOGUE APPROACH JUSTIFICATION
Please find Reporting Format in 'Attached justification'.

4. DATA MATRIX
Please find Data Matrix included in 'Attached justification'.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Test organisms (species):

Cyprinus carpio

Lipid content:

4.3 %

Time point:

start of exposure

Key result

Conc. / dose:

1 mg/L

Temp.:

25 °C

Type:

BCF

Value:

>= 0.2 - <= 0.7 L/kg

Basis:

not specified

Time of plateau:

3 wk

Calculation basis:

steady state

Remarks on result:

other: read-across from analogue.

Key result

Conc. / dose:

0.1 mg/L

Temp.:

25 °C

Type:

BCF

Value:

<= 2.2 L/kg

Basis:

not specified

Time of plateau:

6 wk

Calculation basis:

steady state

Remarks on result:

other: read-across from analogue.

Validity criteria fulfilled:

yes

Remarks:

test parameters were maintained within guideline recommendations.

Conclusions:

Based on the available information for the read-across approach, the BCF of the test item is lower than 2.2 L/kg in carp.

Executive summary:

A bioaccumulation study of the test item in fish was performed on N,N'-dicyclohexylurea (the transformation product of N,N'-dicyclohexylcarbodiimide in water), according to Bioaccumulation test of a chemical substance in fish or shellfish (MITI No.1, 1974), equivalent to OECD 305C. Two levels of concentration as low as possible within the analytical limits (1 mg/L and 0.1 mg/L) were used, based on the results of the 48h-TLm determination of the test item in rice fish (Oryzias latipes), according to JIS K0102. The study was performed for 6 weeks on groups of Cyprinus carpio, along with periodical analytical determinations of the test item concentration in the tank water and in the test specimens by means of a validated analytical method. The BCF was determined at 2, 3, 4 and 6 weeks. In the 1 mg/L concentration level, a BCF of 0.7 L/kg was determined after 3 weeks, and a BCF lower than 0.2 L/kg at the end of the study. In the 0.1 mg/L concentration level, a BCF lower than 2.2 L/kg was determined at all time points. Based on the study results, the BCF of the test item is lower than 2.2 L/kg in carp (worst case scenario). Based on the available information for the read-across approach, the BCF of the test item is lower than 2.2 L/kg in carp.

Description of key information

Read-across from supporting substance (transformation product). Source: Key study. Method according to MITI No.1, equivalent to OECD 305C. The analogue substance has a BCF lower than 2.2 L/kg. Based on the available information for the read-across approach, the BCF of the test item is lower than 2.2 L/kg in carp.

Key value for chemical safety assessment

BCF (aquatic species):

2.2 L/kg ww

Additional information

A bioaccumulation study of the test item in fish was performed on N,N'-dicyclohexylurea (the transformation product of N,N'-dicyclohexylcarbodiimide in water), according to Bioaccumulation test of a chemical substance in fish or shellfish (MITI No.1, 1974), equivalent to OECD 305C. Two levels of concentration as low as possible within the analytical limits (1 mg/L and 0.1 mg/L) were used, based on the results of the 48h-TLm determination of the test item in rice fish (Oryzias latipes), according to JIS K0102. The study was performed for 6 weeks on groups of Cyprinus carpio, along with periodical analytical determinations of the test item concentration in the tank water and in the test specimens by means of a validated analytical method. The BCF was determined at 2, 3, 4 and 6 weeks. In the 1 mg/L concentration level, a BCF of 0.7 L/kg was determined after 3 weeks, and a BCF lower than 0.2 L/kg at the end of the study. In the 0.1 mg/L concentration level, a BCF lower than 2.2 L/kg was determined at all time points. Based on the study results, the BCF of the test item is lower than 2.2 L/kg in carp (worst case scenario). Based on the available information for the read-across approach, the BCF of the test item is lower than 2.2 L/kg in carp.