(2S)-2-amino-3-[3,5-diiodo-4-(4-methoxyphenoxy)phenyl]propanoic 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:

19 March 2019

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)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: O-METHYL-L-DIIODOTHYRONIN
Batch No.: B488840
Appearance: white, powder
Manufacturing date: September 25, 2018
Expiry date: September 24, 2020
Storage condition: at room temperature, protected from light

Analytical monitoring:

yes

Details on sampling:

Actual concentrations of the test substance were determined before the test and after 48 h.
Four replicate samples were analysed from the test solutions at the start and at the end of the experiment.
Four replicate samples were analysed from the control as well.

Vehicle:

no

Details on test solutions:

Reconstituted water (ISO medium, according to OECD 202) was used as dilution water in the experiment. Separate stock solutions of individual substances were first prepared in deionised water (prepared in TOXI-COOP ZRT. by MILLIPORE ELIX 3 water purification system). The ISO medium is prepared by adding 25 mL from each of four stock solutions to one litre deionised water.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species and strain: Daphnia magna (Straus)
Origin: Laboratory of Hydrobiology (Central Agricultural Office, Directorate of Plant-, and Soil Protection)
2100 Gödöllő, Kotlán S. u. 3. Hungary
Breeding: The Daphnia are bred in the Laboratory of TOXI-COOP ZRT.
Number of animals: Twenty animals in both groups (concentration and untreated control), divided into 4 concurrent batches (5 animals per batch).
Age of animals: Less than 24 h old at the beginning of the test.
Sex: Female
Animal health: Apparently healthy animals were used in this test with a known history
Acclimatization: Test animals were bred under similar (or the same) conditions as that used during the exposure period (holding water, temperature, background colour etc.), therefore additional acclimatisation before the test was not necessary. Brood daphnids were maintained in dilution water at the test temperature for at least 48 hours prior to the start of the test.
Food and Feeding: The Daphnia were fed with concentrated algal suspension of Raphidocelis subcapitata during the holding. Test animals were not fed during the exposure.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

The reconstituted water (ISO medium) had an approximate theoretical total hardness of 249 mg/L (as CaCO3).

Test temperature:

The test temperature was in the range of 21.1 – 21.5°C measured in the test vessels during the test. The additionally measured ambient temperature within the climate chamber was between 20.6 – 21.8°C.

pH:

The pH of the test solution was not adjusted and not varied by more than 1.5 units in any one test group. The pH was in the range of 7.29 – 7.88 during the test.

Dissolved oxygen:

The dissolved oxygen concentration was in the range of 7.30 – 7.66 mg/L during the test.

Nominal and measured concentrations:

Toxic effects were not observed during the preliminary test, therefore only one test concentration at saturation (equivalent to 100 mg/L nominal concentration) and one control group were tested in a limit test.
The exposure concentration of the saturated test solution was analytically determined to be 0.57 mg/L (calculated as the geometric mean of start and end concentrations).

Details on test conditions:

The test vessels were kept during the test in a climate chamber under controlled conditions. The temperature, dissolved oxygen concentration and pH were measured in the test item treated and the control group at the start (before test solutions had been distributed into the test vessels) and in each test vessel at the end of the test. Additionally, the ambient temperature was measured continuously using a min/max thermometer in the climate chamber.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 0.57 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.57 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

During the experiment the test item was tested at aquatic saturation (equivalent to 100 mg/L nominal concentration). A concurrent control ran.
The mean measured concentration of the test item was 0.555 mg/L at the start and 0.584 mg/L at the end of the test.
Exposure concentration of the test item was calculated as the geometric mean of the measured start and end concentrations and was determined to be 0.57 mg/L.
Test item was not detected in the control samples.

Validity criteria fulfilled:

yes

Conclusions:

Endpoint Concentration [mg/L]
48 h-EC10 > 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)
48 h-EC20 > 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)
48 h-EC50 > 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)
48 h-NOEC 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)
48 h-LOEC > 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)

Executive summary:

In this 48-hour static acute toxicity test with Daphnia magna the test item O-METHYL-L-DIIODOTHYRONIN had no toxic effect on Daphnia at aquatic saturation (measured value: 0.57 mg/L; equivalent to 100 mg/L nominal concentration). Accordingly, the 48-h EC50 value was determined to be > 0.57 mg/L (equivalent to 100 mg/L nominal concentration). The 48-h NOEC was determined to be 0.57 mg/L (equivalent to 100 mg/L nominal concentration).

All validity criteria were met.

Description of key information

Endpoint                                                 Concentration [mg/L]

48 h-EC10                                                  > 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)

48 h-EC20                                                  > 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)

48 h-EC50                                                  > 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)

48 h-NOEC                                                 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)

48 h-LOEC                                                 > 0.57 mg/L (saturation) (equivalent to > 100 mg/L nominal)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L