(benzothiazol-2-ylthio)succinic acid

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:

2019-11-13 to 2020-01-17

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:

(2004)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

LC-MS/MS method

Details on sampling:

- Concentrations: limit concentration of 100 mg/L and the control (0 mg/L)
- Sampling method: At the start of the exposure (0 hours), samples were taken from the freshly prepared limit concentration and the control and analysed.
At the end of the exposure (48 hours), samples of the old media were taken from one test replicate (containing daphnids) per concentration and control and were analysed.
- Sample storage conditions before analysis: All samples were stored at room temperature until the start of the analysis, if necessary. Prepared samples were stored in the autosampler at room temperature until analysis.

Vehicle:

no

Details on test solutions:

Preparation of the The limit concentration (100 mg/L of the test item were weighed out)
limit concentration was freshly prepared with dilution water prior to the start of the exposure (0 hours). The test item solution was treated with ultrasound for at least 30 minutes at room temperature. Then, undissolved particles were removed by membrane filtration (membrane filter 0.45 µm, RC, MACHEREY-NAGEL). The filter was saturated in order to avoid adsorption during the filtration. The first 25 mL of the filtrate were discarded. The filtration was interrupted for 15 minutes to allow adsorption and saturation of the filter material with dissolved test item. Thereafter, the filtration was continued. The next 25 mL were discarded. During filtration, the filter was always kept covered. The solution was checked via laser beam (Tyndall effect) for undissolved test item. No presence of undissolved test item during the test was observed. The mixing regime was selected based on the observations during the preliminary testing.

Control Dilution water without test item incubated under the same conditions as the test groups
Chemical name of vehicle (organic solvent, emulsifier or dispersant): No vehicle was used

Test organisms (species):

Daphnia magna

Details on test organisms:

Test system: Daphnia magna STRAUS, obtained from continuous laboratory cultures.
Origin: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu), 14195 Berlin, Germany
Breeder: Noack Laboratorien GmbH, Käthe-Paulus-Str. 1, 31157 Sarstedt, Germany
Culture: In glass vessels (2 - 3 L capacity) with approximately 1.8 L culture medium, at 20  2
°C, in an incubator, 16 hours illumination; light intensity of max. 1500 lx
Culture medium: Elendt M4, according to OECD 202, Annex 3 (2004) is used.
Culture feeding: The culture daphnids were fed at least 5 times per week ad libitum with a mix of unicellular green algae, e.g. Pseudokirchneriella subcapitata and Desmodesmus subspicatus. The algae were cultured at the test facility.
Age of parental stock (mean and range, SD): Not specified. Continuous laboratory culture.
Feeding during test: The daphnids were not fed during the study.
Acclimation period: Acclimation of the daphnids was not necessary, because the dilution water was equivalent to the culture medium.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Dilution water: 273 mg CaCO3/L (0 h: start of test)

Test temperature:

18.5- 19.5 °C

pH:

Control
- t(0h) = 7.42
- t(48h) = 7.11
100 mg/L
- t(0h) = 6.20
- t(48h) = 7.12

Dissolved oxygen:

Dilution water:
9.48 mg/L
Control
- t(0h) = 9.48 mg/l
- t(48h) = 8.36 mg/L
100 mg/L
- t(0h) = 8.63 mg/l
- t(48h) = 8.21mg/L

Conductivity:

Dilution water
692 [µS/cm]

Nominal and measured concentrations:

Nominal concentration measured concentration
0 h:
Control < LOQ < LOQ (10 µg/L)
100 mg/L 95.0 mg/L
QC (0.010 mg/L) 0.0107 mg/L

48 h:
Control < LOQ < LOQ
100 mg/L 104 mg/L
QC 0.0105 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (4 (ID) x 7 (H) cm), 50 mL
- Type (delete if not applicable): Loosely covered with watch glasses
- Material, size, headspace, fill volume: 20 mL
- Aeration: No
- No. of organisms per vessel: 20 daphnids
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: According to OECD202
- Total organic carbon: 282 [mg CaCO3/L]
- Alkalinity: pH= 7.42
- Conductivity: 692 [µS/cm]
- Culture medium different from test medium: No
- Intervals of water quality measurement: At the start (t= 0h) and at the end (t= 48h) of the test.
OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16/8 hours light/dark cycle
- Light intensity: Diffuse light, light intensity of max. 1500 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobility/mortality; after 24 and 48 hours.
VEHICLE CONTROL PERFORMED: No vehicle was involved
RANGE-FINDING STUDY: Yes
- Test concentrations: 1; 10 and 100 mg/L prepared with dilution water
- Results used to determine the conditions for the definitive study: Yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (CAS 7778-50-9).

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Behavioural abnormalities: No
- Observations on body length and weight: No
- Other biological observations: No
- Mortality of control: No
- Other adverse effects control: No
- Abnormal responses: No
- 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

Results with reference substance (positive control):

- Results with reference substance valid: Yes
- Relevant effect levels: EC50 (24 h)
- Limit test: no
- Dose-response test: yes
- EC50 (24h): 2.03 mg/l (CI; 1.00 – 4.00)
- Other: Valid range according to AQS P9/2 (02/2000), clone 5 = 0.6 – 2.4 mg/l
-Study period: 2019-12-03 to 2019-12-04

Validity criteria fulfilled:

yes

Conclusions:

Based on the nominal concentration of the test item, the 48-hour EC50 for Daphnia magna was > 100 mg/L.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test item were determined according to OECD 202 (2004).

The study was conducted under static conditions over a period of 48 hours with a limit concentration of 100 mg/L of the test item. The limit concentration was prepared before the start of the exposure period (0 hours) as specified in the section to experimental procedure with dilution water and treated with ultrasound for 30 minutes. Then, undissolved particles were removed by membrane filtration. The limit conccentration was visually clear throughout the exposure. Twenty daphninds (divideed into 4 replicates with 5 daphnids each) were exposed to the limit concentration level and the control.

The concentrations of the test item were analytically verified via LC-MS/MS in the fresh media at the start of the exposure (0 hours) and in the old media at the end of the exposure (48 hours) in the limit concentration and in the control. The measured concentration of the test item at the start of the exposure (0 hours) was 95% of the nominal value. At the end of the exposure period (48 hours), the measured concentration was 104% of the nominal value. The measured test item concentrations remained stable within ± 20% of the nominal concentrations over the test period. This indicates that the test concentrations were successfully maintained for the duration of the test. Therefore, the effect levels given are based on the nominal concentrations of the test item.

The empiric 48 -hour EC50 for Daphnia magna was > 100mg/L.

The validity criteria of the test guideline were fulfilled.

Description of key information

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test item were determined according to OECD 202 (2004).

The study was conducted under static conditions over a period of 48 hours with a limit concentration of 100 mg/L of the test item. The limit concentration was prepared before the start of the exposure period (0 hours) as specified in the section to experimental procedure with dilution water and treated with ultrasound for 30 minutes. Then, undissolved particles were removed by membrane filtration. The limit conccentration was visually clear throughout the exposure. Twenty daphninds (divideed into 4 replicates with 5 daphnids each) were exposed to the limit concentration level and the control.

The concentrations of the test item were analytically verified via LC-MS/MS in the fresh media at the start of the exposure (0 hours) and in the old media at the end of the exposure (48 hours) in the limit concentration and in the control. The measured concentration of the test item at the start of the exposure (0 hours) was 95% of the nominal value. At the end of the exposure period (48 hours), the measured concentration was 104% of the nominal value. The measured test item concentrations remained stable within ± 20% of the nominal concentrations over the test period. This indicates that the test concentrations were successfully maintained for the duration of the test. Therefore, the effect levels given are based on the nominal concentrations of the test item.

The empiric 48 -hour EC50 for Daphnia magna was > 100 mg/L.

The validity criteria of the test guideline were fulfilled.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

The empiric 48 -hour EC50 for Daphnia magna was > 100 mg/L indicating no adverse effects of the test item on Daphnia.