3-chloro-2-[3-(chloroacetyl)-4,5-dihydro-1,2-oxazol-5-yl]phenyl methanesulfonate

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:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 40 mg/L (test item concentration) in the freshly prepared media (on 2017-08-15 and 2017-08-16) and in the media after 24 h of exposure (on 2017-08-16 and 2017-08-17) according to the semi-static conditions
- Sample storage conditions before analysis: Routinely, the samples were analysed immediately. Only in exceptional cases, they were stored overnight deep frozen and protected from light.

Vehicle:

no

Details on test solutions:

PRETREATMENT OF TEST ITEM:
- A stock solution was prepared to give the desired series of test concentrations. 40.3 mg (on 2017-08-15) and 40.8 mg (on 2017-08-16) of the test item were added to 1 litre of to pH 6 adjusted dilution water, treated for 1 h in an ultrasonic bath and stirred for 24 h on a magnetic stirrer. Undissolved particles of the test item were removed by filtration using a folded filter with a pore size of 7 - 12 μm. The pH was measured to be 5.9 on 2017-08-15 and 6.2 on 2017-08-16.
- 50 mL of the solution were taken and diluted with 0.5 mL of dilution water containing 5 daphnids resulting in a final concentration of 100 mg/L. For each test item concentration and the control 4 replicates were prepared.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna STRAUS, parthenogenetic females
- Source: Strain of Bundesgesundheitsamt Berlin

ACCLIMATION
A population of parthenogenetic females of synchronized age structure has been maintained for more than 20 years in the test facility under constant temperature conditions (20 +/- 2 °C) at a 16 : 8 hour light-dark photoperiod (light intensity: < 20 μE x m-2 x s-1). The culture water (so-called 'M4 medium') was partly renewed once a week. The Daphnia were exclusively fed unicellular green algae (Desmodesmus subspicatus) 'ad libitum'. Mortalities of parent Daphnia during the culture period were recorded daily. The neonates were separated from their parent Daphnia by filtration prior to the acute test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

14.8 °dH (= 264 mg/L CaCO3)

Test temperature:

20.5 - 20.8 °C (New medium (0 h) 2017-08-15), 19.6 - 19.8 °C (Old medium (24 h) 2017-08-16)
20.1 - 20.6 °C (New medium (0 h) 2017-08-16), 20.4 - 20.5 °C (Old medium (24 h) 2017-08-17)

pH:

6.0 - 6.1 (New medium (0 h) 2017-08-15), 5.9 - 6.7 (Old medium (24 h) 2017-08-16)
5.8 - 6.1 (New medium (0 h) 2017-08-16), 7.8 - 8.1 (Old medium (24 h) 2017-08-17)

Dissolved oxygen:

8.6 - 9.1 mg/L (New medium (0 h) 2017-08-15), 7.9 - 8.4 mg/L (Old medium (24 h) 2017-08-16)
8.0 - 8.4 mg/L (New medium (0 h) 2017-08-16), 7.8 - 8.1 mg/L (Old medium (24 h) 2017-08-17)

Nominal and measured concentrations:

0.31, 0.63, 1.25, 2.5, 5, 10, 20 and 40 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beakers covered with watch glasses
- Type: closed
- Material, size, headspace, fill volume: 5 neonates in 50 mL of test medium
- Aeration: none
- Medium renewal : daily
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Feeding: no feeding during the exposure period
- Method of initiation : neonates were placed in prepared media
- Temperature of incubation unit : 19.4 to 19.6 °C

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (so-called 'M4 medium' according to OECD 202 and EC Method C.2, annex 1)
- The pH of the dilution water was adjusted to pH 6 before weighing of the test item to reduce hydrolyses processes.
- Medium reneval: daily

OTHER TEST CONDITIONS
- Photoperiod: 16 h light : 8 h dark
- Light intensity: < 20 μE x m-2 x s-1

RANGE-FINDING STUDY
- Test concentrations: 1, 10 and 100 mg/L two range finding tests were peformed. In the second range finding test the pH of the dilution water was adjusted to pH 6 before starting the test.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

2.95 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.96 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Effective concentrations ranged from 15.1 % to 24.5 % in the freshly prepared media and from 7.8 % to 21.3 % in the media after 24 hours of exposure.
- The results are expressed in terms of geometric mean measured concentrations.

Validity criteria fulfilled:

yes

Remarks:

(immobilisation and other abnormalities in the controls did not exceed 10 % by the end of the test; dissolved oxygen concentration remained above 3 mg/L throughout the exposure period)

Conclusions:

For 3-chloro-2-[3-(chloroacetyl)-4,5-dihydro-1,2-oxazol-5-yl]phenylmethanesulfonate an EC 50 (48 h) of 0.96 mg/L was observerd.

Executive summary:

In accordance with the Council Regulation (EC) No 440/2008, Method C.2 ‘Acute toxicity for Daphnia’ (2008) a study was performed to assess the acute toxicity of 3-chloro-2-[3-(chloroacetyl)-4,5-dihydro-1,2-oxazol-5-yl]phenylmethanesulfonate to Daphnia magna STRAUS under semi static conditions. Two range finding tests preceded the main test. It provided information about the range of concentrations which were used in the main test. The following nominal concentrations of the test item were tested in the range finding tests: 1, 10 and 100 mg/L. In the second range finding test the pH of the dilution water was adjusted to pH 6 before starting the test. Daphnia were exposed to the test item added to dilution water at a range of concentrations ( 0.31, 0.63, 1.25, 2.5, 5, 10, 20 and 40 mg/L) for a period of 48 hours. Defined concentrations of test substance led to a certain percentage proportion of immobilised Daphnia at the end of the 48 hour study period. Immobilisation rates were recorded at 24-hour intervals. The EC 50 was calculated by probit analysis using the statistics programme ToxRatPro Version 2.10 (released 2010-09-10). Additionally any abnormal behaviour or appearance of the Daphnia was reported. The main test was conducted as a semi-static test with daily renewal of test medium. During the test a temperature range of 18 - 22 °C was maintained in the test vessels, with a maximum temperature fluctuation of +/- 1 °C in each individual test. The temperature, the pH and the oxygen values were measured every day in the freshly prepared media and in the media after 24 hours of exposure. Observations were made on the swimming ability and the immobilisation rate, respectively, after 24 and 48 hours of exposure.

For the test substance an EC 50 (48 h) of 0.96 mg/L was observerd.

The results are expressed in terms of geometric mean measured concentrations. Effective concentrations ranged from 15.1 % to 24.5 % in the freshly prepared media and from 7.8 % to 21.3 % in the media after 24 hours of exposure.

Description of key information

For 3-chloro-2-[3-(chloroacetyl)-4,5-dihydro-1,2-oxazol-5-yl]phenylmethanesulfonate an EC 50 (48 h) of 0.96 mg/L was observerd.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.96 mg/L