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

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

5-9 May 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The test was conducted according to OECD Guideline 203 and in compliance with GLP. The stock solutions were prepared by agitation for about 22 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 in the range-finding test. 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 LC50 > maximum solubility of the test substance in medium.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples of 5 mL were taken from the limit test solution (LS) at the beginning of the test, before and after each solution change and at the end of the test. They were kept at -20°C until analysis.

Vehicle:

no

Details on test solutions:

The stock solutions, for the limit and range-finding tests, were prepared by dispersing the test item directly in test water.
A loading rate of 100 mg/L was used to prepare the stock solutions (1000 mg in 10L) by agitation of more than 22 hours. As test item particles were still in suspension after agitation, each 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 test water to provide a geometric series of concentratons: 0 mg/L, LS/1000, LS/100, LS/10 for the range-finding test and LS for the limit test..

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Source: CIT, animals were cultured from eggs obtained from Viviers de France, Piscicultures des Fontaines, Sarrance, France.
- Length at study initiation (length definition, mean, range and SD): 40-47 mm
- Weight at study initiation (mean and range, SD): mean was 0.786 g
- Feeding during test: no

ACCLIMATION
- Acclimation period: not stated
- Acclimation conditions (same as test or not): yes, but under flow-through system
- Type and amount of food: trout chow
- Feeding frequency: twice daily, ceasing 24 hours before the start of the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

156 -161 mg CaCO3/L

Test temperature:

13.7 - 14.4 degrees C

pH:

7.7 - 8.1

Dissolved oxygen:

6.8-10 mg/L

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 indicated
- Aeration: not during test
- Renewal rate of test solution (frequency/flow rate): every 24 hours
- No. of organisms per vessel: 5 for the range-finding test; 7 for the limit test
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: less than 1 g fish/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: filtered and dechlorinated potable water which is then softened by a Permo® water softening system. Half of the water passes directly into a holding tank attached to the flow-through system while the remaining half passes through a deionizer producing ultra-pure water which is then fed into the holding tank. This results in a 1:1 dilution of potable dechlorinated: deionized water giving a supply of the desirable hardness. The pH of the solution is between 6.0 and 8.5 and the total hardness is 150 ± 20 mg/L as CaC03.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light/8 hours dark
- Light intensity: not stated

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality at 0, 2, 4, 24, 48, 72 and 96 hours.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: LS/1000, LS/100 and LS/10 (LS = limit of solubility obtained from an initial loading rate of 100 mg/L)
- Results used to determine the conditions for the definitive study: In the range-finding test, the mortality at LS/1000, LS/100 and LS/10 was also 0% after 96 hours.

Reference substance (positive control):

no

Key result

Remarks on result:

other: LC50 (96h): > maximum soluble concentration of test substance in test medium

Details on results:

In the limit test, all animals exposed to the LS solution were alive after 96 hours. No sub-lethal effect was observed in any group.

The report concluded that the 96h LC50 was > 100 mg/L (initial loading rate). The French Authorities reported the 96h LC50 as > 0.01 mg/L (measured initial).

Results with reference substance (positive control):

None

Sublethal observations / clinical signs:

Validity of the criteria:

- mortality in the controls did not exceed 10%

- constant conditions were maintained under semi-static conditions

- dissolved oxygen concentrations were above 60% of the air saturation value.

Validity criteria fulfilled:

yes

Conclusions:

The 96-h LC50 value in fish 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 rainbow trout was assessed according to the OECD 203 guideline and following GLP principles. Under the experimental semi-static 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 LC50 is above the maximum solubility limit of the test substance in test medium.

Description of key information

The 96-h LC50 value in fish 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 rainbow trout was assessed according to the OECD 203 guideline and following GLP principles. Under the experimental semi-static 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 LC50 is above the maximum solubility limit of the test substance in test medium.