A mixture of: 2,4 -bis(N'-(4-methylphenyl)ureido)toluene; 2,6 -bis(N'-(4-methylphenyl)ureido)toluene

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 December 1992 - 23 March 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles. Limited information available to verify the composition of the used test substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

(1984)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

A mixture of: 2,4 -bis(N'-(4-methylphenyl)ureido)toluene; 2,6 -bis(N'-(4-methylphenyl)ureido)toluene

EC Number:

411-070-0

EC Name:

A mixture of: 2,4 -bis(N'-(4-methylphenyl)ureido)toluene; 2,6 -bis(N'-(4-methylphenyl)ureido)toluene

Molecular formula:

C23H24N4O2

IUPAC Name:

3-(2-methyl-5-{[(4-methylphenyl)carbamoyl]amino}phenyl)-1-(4-methylphenyl)urea

Details on test material:

- Name of test material (as cited in study report): KY-ET
- Substance type: light yellow solid
- Physical state: solid
- Stable for at least 48h in water: Yes
- Storage condition of test material: RT in the dark
- Stability under storage conditions: Stable

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Duplicate samples were taken from all replicate test vessels, the Cremophor control and the supersaturated solutions.
- Sampling method: 10 mL from center of test vessels at t=0h, t=96h; ALSO, 10 mL taken from top and bottom of one vessel to determine homogeneity
- Sample storage conditions before analysis: t = 0 samples were stored at -20 degrees C until analysis. t = 96h samples were analysed on the day of sampling.

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: weighed amounts were mixed with Cremophor RH40 and these mixtures were added to 4L of ISO-medium and stirred for 67h
- Controls: blank, Cremophor RH40
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Cremophor RH40
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 0.1 g/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc): During the test, substance deposits were observed at the bottom of the vessels.

Test organisms

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: Carp
- Source: Zodiac, proefacc, "De Haar Vissen", L.U. Wageningen, The Netherlands
- Length at study initiation (length definition, mean, range and SD): 2.3 +/- 0.14 cm
- Weight at study initiation (mean and range, SD): 0.28 +/- 0.07 g
- Method of breeding: pathogen-free F1 from a single parent pair

ACCLIMATION
- Acclimation period: at least 14 days
- Acclimation conditions (same as test or not): Same except with feeding (no feeding during the test and 24h prior to the start of test)
- Type and amount of food: Trouvit or Artemia
- Feeding frequency: daily
- Health during acclimation (any mortality observed): less than 5% mortality during the 7 days prior to the test period

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test conditions

Hardness:

250 mg CaCO3/L

Test temperature:

18-20.5 degrees Celsius

pH:

7.9-8.1

Dissolved oxygen:

9.0-9.6 mg/L

Nominal and measured concentrations:

Nominal concentrations in the final test were set to 1000 mg/L. Aliquots from the start and end of the test were assessed via HPLC-UV and showed concentrations of 337 - 588 mg/L at the start of the test and 222 - 318 mg/L at the end of the test. The overall average concentration was 358 mg/L (measured). Tested concentrations were significantly above the solubility of KY-ET in water (0.002 mg/L).

Details on test conditions:

TEST SYSTEM
- Material, size, fill volume: all-glass, 4 L vessels
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: 0.7 g fish/L

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16h daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality at 5.5, 24, 54, 72 and 96 hours

TEST CONCENTRATION

1000 mg/L (nominal)

Reference substance (positive control):

yes

Remarks:

pentachlorophenol

Results and discussion

Effect concentrations

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 358 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Overall average value (note: there was variability in test concentrations between replicate vessels)

Details on results:

- Behavioural abnormalities: none observed
- Mortality of control: 0
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: substance deposits at bottom of vessels
- Effect concentrations exceeding solubility of substance in test medium: Yes

- Measured test concentrations: t=0: 565/588 (A), 369/337(B), 398/408 (C) mg/L; t=96h: 318/298 (A), 287/265 (B), 239/222 (C) mg/L
- Homogeneity test (replicate B, mean of duplicate samples taken at a height of 90%, 50% and 10%, respectively): t= 0: 370, 353 and 396 mg/L, t = 96h: 373, 276 and 282 mg/L.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Mortality: 0 of 3 fish died at 0, 0.1 and 0.18 mg/L, 3 of 3 fish died at 0.32, 0.56 and 1.0 mg/L
- LC50: between 0.18 and 0.32 mg/L

Any other information on results incl. tables

Sublethal observations / clinical signs:

The measured test concentrations in medium were much higher (a factor 10^5) than the maximum solubility in water (0.002 mg/L). No effects were observed at the tested concentration. Based on the overall average measured test concentration, the 96h-LC50 value was determined to ne higher than 358 mg/L. Since this exceeds the maximum solubility of KY-ET in water (0.002 mg/L), it can be concluded that the 96h-LC50 value is above the maximum solubility in water of KY-ET.

Although there is variability of measured concentrations between the test vessels, the homogeneity test revealed that there is little variability between measured concentrations within a test vessel (at different heigths).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The measured 96-h LC50 of KY-ET was higher than 358 mg/L, which is higher than the maximum solubility of KY-ET in water (0.002 mg/L).

Executive summary:

A 96-h Acute toxicity test was performed in carp. The test substance was stirred for 67 hours to achieve maximum concentration possible in the test. Cremophore was used as a dispersant. There was no mortality observed in the time-frame of the test. The measured 96-h LC50 of KY-ET was higher than 358 mg/L, which is higher than the maximum solubility of KY-ET in water (0.002 mg/L).