2[2'-Hydroxy-5'-(phenyl)ureylenphenyl]benzothiazole

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 Mar 2018 to 06 Apr 2018.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

Adopted April 13,2004.

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

no

Remarks:

No analytical monitoring was carried out due to the low solubility of the test item .

Details on sampling:

- Concentrations: 1.0, 10 and 100% of the SS prepared at a loading rate of 100 mg/L.
2 replicates of each test concentration,
4 replicates of the control and limit concentration

- Sampling method:
Samples for possible analysis were taken from all test concentrations and the control.
In addition, the filter containing the undissolved residue was kept for possible analysis.
Frequency at t=0 h and t=48 h
Volume 2.0 mL from the approximate centre of the test vessels.

- Sample storage conditions before analysis:
Samples were stored in a freezer (≤-15°C) until analysis at the analytical laboratory of the Test Facility.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

The substance tested was a slight yellow powder with a purity of 98% which was not completely soluble in test medium at the loading rate initially prepared.
No correction was made for the purity/composition of the test item.

Preparation of test solutions started with a loading rate of 100 mg/L applying an overnight period of magnetic stirring to ensure maximum dissolution of the test item in medium.

Thereafter, the aqueous Saturated Solution (SS) was collected by filtration through a 0.45 µm membrane filter (RC55, Whatman) and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS in test medium. The SS was clear and slightly yellow, while the dilutions were clear and colourless at the end of the preparation period.

Any residual volumes were discarded.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
- Source: In-house laboratory culture with a known history.
- Age of parental stock : parental daphnids of more than two weeks old.
animals and there was no delay in the production of the first brood.
- Feeding during test: No feeding during test period

ACCLIMATION
Breeding
Start of each batch With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an
all-glass culture vessel.
Maximum age of the cultures 4 weeks Renewal of the cultures After 7 days of cultivation half of the medium twice a week.
Temperature of medium 18-22°C
Feeding Daily, a suspension of fresh water algae.
Medium M7, as prescribed by Dr. Elendt-Schneider (Elendt, B.-P., 1990: Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus. Protoplasma 154, 25-33).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

180 mg/L expressed as CaCO3 and the pH: 7.7 ± 0.3

Test temperature:

19-20°C

pH:

7.9 -8.2

Dissolved oxygen:

8.6-9

Nominal and measured concentrations:

Solutions containing 1.0, 10 and 100% of the SS prepared at a loading rate of 100 mg/L.
Samples taken from the undiluted SS were analysed. Test item concentrations were below the
Limit of Quantification (LOQ), i.e. 0.008 mg/L, throughout the test. Nevertheless, it can be stated that testing was ultimately performed at the maximum soluble concentration of test item in test medium. Analysis of the filter residue demonstrated the use of the test item during preparation of test solutions.

Details on test conditions:

TEST SYSTEM
- Test vessel: 60 mL, all-glass
- fill volume: vessel containing 50 mL of test solution - static
- Aeration: No aeration of the test solutions
- No. of organisms per vessel: 5 (Control and limit concentration: 20 per test group / Intermediate concentrations: 10 per concentration)
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 4 for Control and limit concentration

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water purified by Reverse Osmosis
- Medium: M7, as prescribed by Dr. Elendt-Schneider (Elendt, B.-P., 1990: Selenium deficiency in Crustacea.An ultrastructural approach to antennal damage in Daphnia magna Straus. Protoplasma 154, 25-33).

OTHER TEST CONDITIONS
- Adjustment of pH: No adjustment
- Photoperiod: 16 hours photoperiod daily

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

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Key result

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

K2Cr2O7:
The 24h-EC50 was 0.80 mg/L with a 95% confidence interval between 0.71 and 0.90 mg/L.
The 48h-EC50 was 0.33 mg/L with a 95% confidence interval between 0.29 and 0.38 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48h-EL50 for Daphnia magna exposed to test item exceeded the maximum solubility of the test item in test medium.

It can be stated that the test was conducted at the maximum soluble concentration of the test item in test medium, starting at a loading rate of 100 mg/L.

The actual exposure concentration could not be measured and was below 0.008 mg/L, the Limit of Quantification of the analytical method.

Executive summary:

The objective of the study was to evaluate test item for its ability to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours and, if possible, to determine the EC50 at 24 and 48 hours of exposure.

The study procedures described in this report were based on the OECD guideline No. 202, 2004. In addition, procedures were based on the test methods described in the OECD series on testing and assessment number 23, 2000.

The batch of test item tested was a slight yellow powder with a purity of 98% which was not completely soluble in test medium at the loading rate initially prepared. A Saturated Solution (SS) was prepared at a loading rate of 100 mg/L and used as the highest test concentration. Lower concentrations were prepared by diluting the highest test concentration in test medium.

A combined limit/range-finding test was performed. Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and undiluted SS prepared at a loading rate of 100 mg/L, in a limit test. In addition ten daphnids per group (5 per replicate, duplicate) were exposed to solutions containing 1.0 and 10% of the SS in the combined range-finding test.

The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test.

No biological relevant immobility (i.e. >10%) was observed in the control and at any test concentration throughout the test.

Samples taken from the undiluted SS were analysed. The test item concentrations were below the Limit of Quantification (LOQ), i.e. 0.008 mg/L, throughout the test. Analysis of the filter residue demonstrated the use of the test item during preparation of test solutions.

The study met the acceptability criteria prescribed by the study plan and was considered valid.

In conclusion, the 48h-EL50 for Daphnia magna exposed to test item exceeded the maximum solubility of the test item in test medium. It can be stated that the test was conducted at the maximum soluble concentration of the test item in test medium, starting at a loading rate of 100 mg/L. The actual exposure concentration could not be measured and was below 0.008 mg/L, the Limit of Quantification of the analytical method.