N,N''-(methylenedi-4,1-phenylene)bis[N'-octylurea]

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 April-1 May 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The test was conducted according to OECD Guideline 202 and in compliance with GLP. The stock solutions were prepared by agitation for 24 hours and then filtered twice (porosity of 4-7 µm and then of 0.45 µm). The filtered solution was then further used to prepare the test solutions of the range-finding study. The measured concentrations of test substance in these solutions were below the limit of quantification (0.01 mg/L) at all measurement times. Based on the fact that the substance is highly insoluble in water (< 3 µg/L) and has a high adsorptive potential (Koc > 5.6), it can only be concluded that the EC50 > maximum solubility of the test substance in medium.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

A sample of 5 mL was taken from the limit test solution container (LS solution) at the beginning of the test and kept at -20°C until analysis.
Samples of 5 mL were also taken at T24 and T48 hours from the LS test vessels containing daphnids and kept at -20°C until analysis.

Vehicle:

no

Details on test solutions:

The stock solution, for the limit and range-finding tests, was prepared by dispersing the test item directly in M4 reconstituted water.
A loading rate of 100 mg/L was used to prepare the stock solution with 24 hours agitation. As test item particles were still in suspension after agitation, the stock solution was filtered through a filter of porosity 4-7 µm and then a filter of porosity 0.45 µm to remove the suspended fraction. The filtered solution, corresponding to the limit of solubility of the test item under the experimental conditions (LS), was then used to prepare the test solutions. Test solutions were prepared by further dilution of this LS solution with M4 reconstituted water to provide a geometric series of concentrations: 0 mg/L, LS/1000, LS/100, LS/10 for the range-finding study and LS for the limit test.
Test vessels containing daphnids were filled directly from the test solution containers immediately after preparation and test solutions remained unchanged.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: STRAUS-clone 5
- Source: Centre Technique du Bois et de l'Ameublement CIT), 75012 Paris, France
- Age at study initiation (mean and range, SD): at the beginning of the test, first instar daphnids between 6 and 24 hours old and produced from parthenogenically reproducing brood female population.
- Feeding during test: no

ACCLIMATION
- Acclimation period: animals were held in water of the same quality as the test water from birth until use in the test. The medium was replaced generally each Monday, Wednesday and Friday. On each of these occasions, neonates were separated from the adults and either removed or, once monthly, used to start a new culture. During culture, pH, water hardness and dissolved oxygen concentrations were checked in the "new" and "old" media when solutions are replaced generally twice a week.
- Acclimation conditions (same as test or not): yes
- Type and amount of food: Culture animals were fed with a diet of between 0.1 and 0.2 mg of carbon per Daphnia per day, in the form of the algal strain Scenedesmus subspicatus which is cultured at CIT.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

272 mg CaCO3/L

Test temperature:

19-20 ºC

pH:

7.6-8.0

Dissolved oxygen:

8.3 and 8.6 mg/L (> 60% of the air saturation)

Salinity:

Not applicable.

Nominal and measured concentrations:

LS = limit of solubility obtained from an initial loading rate of 100 mg/L for the limit test
Measured concentrations in the LS solution were below the limit of quantification (0.01 mg/L) throughout the test.

Details on test conditions:

TEST SYSTEM
- Test vessel: not stated
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 5

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted (M4). The pH of this solution is 8.0 ± 0.5; total hardness is generally between 238 and 289 mg/L as CaC03.
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 18 hurs light/8 hours dark
- Light intensity: not stated

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilization at 0, 24 and 48 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit test
- Range finding study: Test concentrations: LS/1000, LS/100 and LS/10
- Results used to determine the conditions for the definitive study: no immobilization was observed at any tested concentration throughout the test

Reference substance (positive control):

no

Key result

Remarks on result:

other: EC50 (48h): > maximum soluble concentration of test substance in test medium

Details on results:

No immobilization was observed at 0 mg/L, LS/1 000, LS/1 00, LS/1 0 and LS throughout the test.
The report concluded that the 48h EC50 was > 100 mg/L (initial loading rate). The French Authorities reported the 48h EC50 as > 0.01 mg/L (measured initial).

Results with reference substance (positive control):

None

Reported statistics and error estimates:

None

Validity criteria:

- not more than 10% of the Daphnia were immobilized in the controls

- the dissolved oxygen concentration was > 60 % of the air saturation value at the temperature used.

Validity criteria fulfilled:

yes

Conclusions:

The 48 -h EC50 in Daphnia magna is higher than the limit of solubility in test medium at a nominal loading rate of 100 mg/L.

Executive summary:

The effect of the test substance on the acute toxicity of Daphnia magna was assessed according to the OECD 202 guideline and following GLP principles. Under the experimental conditions, no effects were observed in the limit test, conducted with the filtrate of a 100 mg/L loading rate. The measured concentration of test substance was < LOQ (0.01 mg/L) throughout the test. It is thus assessed that the EC50 is above the maximum solubility limit of the test substance in test medium.

Description of key information

The 48-h EC50 in Daphnia magna is higher than the limit of solubility in test medium at a nominal loading rate of 100 mg/L.

Additional information

The effect of the test substance on the acute toxicity of Daphnia magna was assessed according to the OECD 202 guideline and following GLP principles. Under the experimental conditions, no effects were observed in the limit test, conducted with the filtrate of a 100 mg/L loading rate. The measured concentration of test substance was < LOQ (0.01 mg/L) throughout the test. It is thus assessed that the EC50 is above the maximum solubility limit of the test substance in test medium.