N,N’-di[3-(p-toluene sulfonyl)oxy]phenyl urea

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

April 13, 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: "Daphnia sp. Acute immobilization test" - Testing method for New Chemical Substances of Japanese Chemical Substances Control Law

Version / remarks:

July 1, 2019

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD Guidance Document No. 23

Version / remarks:

February 2019
Guidance Document on Aqueous-phase Aquatic Toxicity Testing of Difficult Test Chemicals

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: single concentration (nominal concentration: 100 mg/L)
- Sampling method: Solution sampled separately from the preparation container (at start of exposure); mixed solution was taken out with equal volumes from the middle layer of the test solution in the test vessels in each test level (at the end of exposure)
- Sample storage conditions before analysis: samples were analysed straightaway after collection.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A saturated solution was prepared. 100g test item and 1000mL dilution water were mixed to produce the test concentration 100 mg/L and stirred by a magnetic stirrer for 48h at approx. 20°C to prepare the test solution. The test solution was divided into each test vessel.
- Controls: Dilution water (negative control) prepared using the same method as the test solution but no test item added
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): No used; not applicable
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): not applicable
- Test concentration separation factor: not applicable (limit test)
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): yes: white suspension, precipitation and insoluble matter were observed.
- Other relevant information: undissolved test item had no physical effect on the test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia manga (water flea)
- Strain/clone: Clone A
- Justification for species other than prescribed by test guideline: Species recommended by test guideline
- Age at study initiation (mean and range, SD): Less than 24 hours
- Method of breeding: Young daphnids produced by parents in the test facility. The parents to obtain the young daphnids were bred in the same quality of water as used in the study.
- Source: University of Sheffield, UK
- Age of parental stock (mean and range, SD): 21 days old
- Feeding during test: no
- Food type: not applicable
- Amount: not applicable
- Frequency: not applicable

ACCLIMATION
- Acclimation period: not specified
- Acclimation conditions (same as test or not): yes
- Type and amount of food: Chlorella vulgaris 0.1-0.2 mgC (organic carbon content)
- Feeding frequency: once per day
- Health during acclimation (any mortality observed): not reported

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Remarks on exposure duration:

As recommended in the guideline

Post exposure observation period:

Not applicable.

Test temperature:

20°C 

pH:

7.9

Dissolved oxygen:

8.7 mg/L at start of exposure
8.5 mg/L at end of exposure

Nominal and measured concentrations:

Nominal: 100 mg/L
Measured: 0.00124 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beaker
- Type (delete if not applicable): open - transparent plastic lid
- Volume of solution: 100 mL
- Aeration: no
- No. of organisms per vessel: 5 daphnids/vessel
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated tap water, aerated sufficiently and temperature controlled
- Total organic carbon: <0.5 mg/L
- Particulate matter: <1 mg/L
- Metals: - Pesticides: - Chlorine: <0.02 mg/L
- Alkalinity: 39 mg/L
- Ca/mg ratio: 44 mg/L

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: Room light, 16-hour light, 8 hours dark
- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilisation, 24 hours and 48 hours after exposure. Immobilisation considered when daphnids not able to swim for 15 seconds after gentle agitation of the test vessel

VEHICLE CONTROL PERFORMED: no - no vehicle used

RANGE-FINDING STUDY
- Test concentrations: 100 mg/L (saturated solution)
- Results used to determine the conditions for the definitive study: yes.

Reference substance (positive control):

yes

Remarks:

Not conducted in parallel with study but lab conducts positive controls periodically to confirm the reproducibility of the test system. Period of study - April 16 - April 18 48h EC50 = 0.22 mg/L

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: No immobilisation was observed during the test.

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.001 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Remarks on result:

other: Limit of solubility of the test item. No immobilisation was observed during the test.

Details on results:

- Other adverse effects control: no
- Immobilisation of control: no
- Abnormal responses:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no effects observed

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: 48h EC50 = 0.22 mg/L
- Limit test: yes

Reported statistics and error estimates:

None

Table 1: Immobility results

Measured concentration^a (mg/L)	Vessel	24hours		48 hours
		No. of immobilised daphnids/Total daphnids	Immobility (%)	No. of immobilised daphnids/Total daphnids	Immobility (%)
Control	A	0 / 5	0	0 / 5	0
	B	0 / 5		0 / 5
	C	0 / 5		0 / 5
	D	0 / 5		0 / 5
0.00124	A	0 / 5	0	0 / 5	0
	B	0 / 5		0 / 5
	C	0 / 5		0 / 5
	D	0 / 5		0 / 5

^aTime-weighted mean of the measured concentrations (also expressed as mesured concentration in the following tables)

Table 2: Observed abnormal response

Measured concentration (mg/L)	Observed abnormal response
	24 hours	48 hours
Control	-	-
0.00124	-	-

Table 3: EC50 values to Daphnia magna

Exposure duration	EC50 (mg/L)
24 hours	>0.00124
48 hours	>0.00124

 

Table 4: Measured concentration of the test item in test solution

Nominal concentration (mg/L)	Measured concentration (mg/L) (percentage of measured concentration versus that at the start %)
	At the start	At the end	Time-weighted average mean
Control	<LOQ	<LOQ	-
100	0.000360	0.00299 (830)	0.00124

LOQ = 0.0002 mg/L

The time weighted mean is calculated by the following calculation:

[48 (C₀-C₄₈)/(lnC₀-lnC₄₈]/48

C_n: the measured concentration at n hours

lnC_n: the natural logarithm of C_n

Validity criteria fulfilled:

yes

Remarks:

Dissolved oxygen was >3 mg/L at the end of exposure

Conclusions:

No immobilisation was observed during the limit test. The 48h EC50 was calculated as >0.00124 mg/L greater than the solubility of the test item in the test water.

Description of key information

In a study conducted in accordance with OECD Guideline 202 on Daphnia Magna, the 48h EC50 >100 mg/L (nominal) was reported.  Based on measured concentrations, no immobilisation was observed up to the limit of solubility of the test item (TWA measured with analytical verification at 0.00124 mg/L). 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 100 mg/L