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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:

2018

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:

not applicable

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

HPLC/MS

Details on sampling:

Sampling schedule:
- Control: at 48 hours (on 2018-03-01)
- Test concentration/s: 6.25, 12.5, 25, 50 and 100 mg/L in the freshly prepared media (on 2018-02-27 and 2018-02-28)
and in the media after 24 h of exposure (on 2018-02-28 and 2018-03-01) according to the semi-static conditions

Vehicle:

no

Details on test solutions:

Pre-treatment of test item and preparation of test item concentrations:
- A stock solution was prepared to give the desired series of test concentrations. 99.9 mg of the test item were added to 1 litre of dilution water on 2018-02-26 and 100.7 mg of the test item were added to 1 litre of dilution water on 2017-10-27, treated for 60 seconds at 8000 rpm with an ultra turrax 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 and an aseptic filter Sartobran sterile capsules (pore size of 0.45 µm + 0.2 µm)
- The pH was measured to be 7.9 on 2018-02-27 and 7.8 on 2018-02-28.
- To produce the different test item concentrations appropriate amounts of the stock solution were diluted with dilution water to a volume of 500 mL

Test organisms (species):

Daphnia magna

Details on test organisms:

- Daphnia magna STRAUS, parthenogenetic females
- Source: Strain of Bundesgesundheitsamt Berlin
- Maintenance and Acclimatisation: 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 with unicellular green algae (Desmodesmus subspicatus) 'ad libitum'. Mortalities of parent Daphnia during the culture period were recorded daily in a semi-quantitative way. The neonates were separated from their parent Daphnia by filtration prior to the acute test
- Culture and dilution water: Reconstituted water (so-called 'M4 medium' according to OECD 202 and EC Method C.2, annex 1)

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:

20.7 °C (new medium) / 19.8 °C (old medium) concerning 100 mg/L test concentration

pH:

7.9 (new medium) / 8.0 (old medium) concerning 100 mg/L test concentration

Dissolved oxygen:

8.1 mg/L (new medium) / 8.2 mg/L (old medium) concerning 100 mg/L test concentration

Salinity:

n.a.

Conductivity:

No data

Nominal and measured concentrations:

- Test concentration (nominal): 100 mg/L
- Test concentration after 48 hours (HPLC/MS/MS values): 0.038685 mg/L

Details on test conditions:

Exposure conditions
- Test vessels: 100 mL glass beakers covered with watch glasses holding 5 neonates in 50 mL of test medium
- Experimental design: 5 test concentrations plus 1 control; 5 neonates per vessel, 4 replicates per concentration/control;
- Feeding: none during the exposure period
- Method of initiation: neonates were placed in prepared media
- Photoperiod: 16 h light : 8 h dark
- Temperature of incubation unit: 19.6 to 19.8 °C
- Aeration: none
- Test item concentration/s: 6.25, 12.5, 25, 50 and 100 mg/L (nominal)
- Method of administration: stock solution (100 mg/L)
- Medium renewal: daily
- Criteria of effects:item-induced alteration of the normal mobility behaviour and the loss of locomotory actions of the neonates, observed at 24 and 48 hours

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.05 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % confidence limits 0.036–0.097 (mg/L)

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 0.111 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 0.059 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Effective concentrations ranged from 0.04 % to 0.18 % in the freshly prepared media and from 0.03 % to 0.11 % in the media after 24 hours of exposure

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:

After 48 hours of exposure an EC50 value of higher than 0.05 mg/L was determined for daphnids. No toxic effects against daphnia were observed at the limit of water solubility under exposure conditions (for details see also chapter 4.8). The results are expressed in terms of geometric mean measured concentrations. Effective concentrations ranged from 0.04 % to 0.18 % in the freshly prepared media and from 0.03 % to 0.11 % in the media after 24 hours of exposure.

Executive summary:

A study was performed to assess the acute toxicity to Daphnia magna STRAUS under semi-static conditions. The study was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.2 ‘Acute toxicity for Daphnia’ (2008) which is equivalent to OECD Guideline for Testing of Chemicals No. 202 'Daphnia sp., Acute Immobilisation Test' (adopted April 13, 2004). The Daphnia were exposed to a range of concentrations, nominally 6.25, 12.5, 25, 50 and 100 mg/L of test material dissolved in dilution water. A range finding test 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 test: 1, 10 and 100 mg/L. In the main test, Daphnia were exposed to the test item added to dilution water at a range of concentrations for a period of 48 hours. Defined concentrations of the test item 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. The validity criteria of the test were met. No toxic effects against daphnia were observed at the limit of water solubility under exposure conditions (for details see also chapter 4.8). The results are expressed in terms of geometric mean measured concentrations. Effective concentrations ranged from 0.04 % to 0.18 % in the freshly prepared media and from 0.03 % to 0.11 % in the media after 24 hours of exposure. This toxicity study is classified as acceptable and satisfies the guideline requirements for the toxicity study to daphnia.

Description of key information

After 48 hours of exposure an EC50 value of higher than 0.05 mg/L was determined for daphnids. No toxic effects against daphnia were observed at the limit of water solubility under exposure conditions (for details see also chapter 4.8). The results are expressed in terms of geometric mean measured concentrations. Effective concentrations ranged from 0.04 % to 0.18 % in the freshly prepared media and from 0.03 % to 0.11 % in the media after 24 hours of exposure (Woelz, 2018).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.05 mg/L

Additional information

"Should read: 48 h-EC 50 >0.05 mg/L"