2,2-bis[[(mercaptoacetyl)oxy]methyl]-1,3-propanediyl bis(mercaptoacetate)

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:

2018-08-03 to 2018-11-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guideline; EU Method; GLP

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:

other: OECD Series on Testing and Assessment, No. 23, "Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures"

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: PETMA
Chemical Name: Pentaerythritoltetra(mercaptoacetat)
CAS No.: 10193-99-4
Batch No.: 0061491
Purity: 96.9 % according to certificate of analysis
CoA Reference No.: PROJEKT 13167
Manufacturing Date: July 17, 2018
Aggregate State at Room Temperature: Solid
Colour: Colourless
Expiry Date: January 15, 2019
Storage Conditions at Test Facility: At 20 +/- 5 °C, in the dark

Analytical monitoring:

yes

Remarks:

HPLC-UV

Details on sampling:

Duplicate samples from the freshly prepared test media of all test concentrations and the control were taken at the start of the test and at day 1.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, duplicate samples from the aged test media of all test concentrations and the control were collected at day 1 (after 24 hours of exposure) and at the end of the test by pouring together the contents of the test beakers of each treatment.
All samples were diluted by a factor of 2 with acetonitrile.
Additional samples of the control and the dilution solvent were taken at each sampling without any sample treatment.

Vehicle:

no

Details on test solutions:

Test Concentrations:
Due to the low limit of water solubility of the test item, a filtrate of nominal 100 mg/L and dilutions of 1:2, 1:4, 1:8 and 1:16 of this filtrate were tested. Additionally, a control was tested in parallel.
This filtrate and its dilutions correspond to the following geometric mean measured concentrations of the test item: 1.06, 0.390, 0.178, 0.0564 and 0.0392 mg test item/L, and a control. Control: In the control, test water was used without addition of the test item.
Dosage of Test Item:
The test item is not well soluble in test medium. To avoid physical effects of undissolved test item on the daphnids, no concentrations above the solubility limit of the test item in test water was tested. Therefore, a supersaturated stock solution of nominal 100 mg test item/L was prepared by suspending 100.8 and 100.8 mg test item in 1008 and 1008 mL test water. The stock suspension was stirred for 24 hours at room temperature in the dark to dissolve as much test item as possible. Then, non-dissolved fractions of the test item were separated from the test medium by membrane filtration (0.45 µm cellulose acetate filter). The solution with dissolved test item was used as the test medium of the highest test concentration and to prepare the desired 1:2, 1:4, 1:8 and 1:16 dilutions. The test media were prepared just before introduction of the daphnids (= start of the test) and test medium renewal on Day 1.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species:Daphnia magna (Straus), clone 5
Age at Test Start:From 5.75 to 22.75 hours old
Sex:Female
Origin:The Daphnia introduced in the test were taken from ibacon's in house laboratory culture.
Breeding Conditions:The Daphnia were bred in the laboratories of ibacon under similar temperature and light conditions as used in the test. The cultivation of the parental Daphnia was performed in Elendt M4 medium. The test organisms were not first brood progeny. The Daphnia in the stock culture were fed at least on all working days with green algae (Desmodesmus subspicatus) freshly grown in the laboratories of ibacon.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Water Hardness: 2.5 mmol/L (= 250 mg/L) as Calcium Carbonate

Test temperature:

20.8 to 21.5 °C in the freshly prepared media;
20.4 to 21.1°C in the aged test media

pH:

7.8 to 8.1 in the freshly prepared media;
7.8 to 7.9 in the aged test media; and thus the pH-value did not vary by more than 1.5 units

Dissolved oxygen:

5.7 to 8.9 mg/L in the freshly prepared media;
8.4 to 8.7 mg/L in the aged test media

Nominal and measured concentrations:

Due to the low limit of water solubility of the test item, a filtrate of nominal 100 mg/L and dilutions of 1:2, 1:4, 1:8 and 1:16 of this filtrate were tested. Additionally, a control was tested in parallel.
This filtrate and its dilutions correspond to the following geometric mean measured concentrations of the test item:
1.06, 0.390, 0.178, 0.0564 and 0.0392 mg test item/L, and a control.

Details on test conditions:

Test Environment:
Controlled environment room
Measurement of pH, Dissolved Oxygen and Water Temperature:
The water temperature, pH-values and the dissolved oxygen concentrations were determined in all freshly prepared and aged test media of each treatment group.
Water Temperature:
20.8 to 21.5 °C in the freshly prepared media;
20.4 to 21.1°C in the aged test media
pH-Values:
7.8 to 8.1 in the freshly prepared media;
7.8 to 7.9 in the aged test media; and thus the pH-value did not vary by more than 1.5 units Dissolved Oxygen Concentration:
5.7 to 8.9 mg/L in the freshly prepared media;
8.4 to 8.7 mg/L in the aged test media
Light Regime: 16 h light : 8 h dark
Light Intensity: The light intensity was 350 to 600 lux (measured once during the test).

Reference substance (positive control):

yes

Remarks:

For the evaluation of the quality of the Daphnia clone and the consistency of the experimental conditions, the reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 1.06 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 1.06 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 1.06 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

After 48 hours of exposure no immobilisation of the test animals was observed in the control and all test concentrations up to a geometric mean measured concentration of 1.06 mg test item/L.

Results with reference substance (positive control):

In the most recent test with the reference item potassium dichromate the EC50 after 24 hours was determined to be 1.58 mg test item/L, indicating that the sensitivity of the Daphnia was consistent with the level proposed by the OECD 202 guideline (EC50-24 h between 0.6 and 2.1 mg potassium dichromate/L).

Reported statistics and error estimates:

No statistical analysis was performed.
The EC50 could not be quantified due to the absence of toxicity of the test item. The NOEC and the LOEC were determined directly from the raw data.

Validity criteria fulfilled:

yes

Remarks:

Control Immobilisation Rate was 0 % and furthermore no daphnid showed signs of disease or stress. Dissolved Oxygen Concentration was above or equal 8.4 mg O2/L in the control and test vessels at the end of the test.

Conclusions:

The toxic effect of the test item PETMA to Daphnia magna was assessed in a semi-static concentration-response test. The 48-hour NOEC was determined to be ≥ 1.06 mg test item/L. The 48-hour LOEC was determined to be > 1.06 mg test item/L and the 48-hour EC50 value was calculated to be > 1.06 mg test item/L.
The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to geometric mean concentrations, since the test item concentrations were not within ± 20 % of the measured initial concentrations during the test.

Executive summary:

Title: PETMA: Acute Toxicity to Daphnia magna in a Semi-Static 48-hour Immobilisation Test

Purpose:

The purpose of this study was to determine the influence of the test item PETMA on the mobility of Daphnia magna. For this purpose, young daphnids (< 24 hours old) were exposed in a semi-static test to various concentrations under defined conditions for 48 hours. The recorded effects were the mobility of the daphnids after 24 and 48 hours. The test method of application and the test system are recommended by the test guidelines and Daphnia magna is the recommended test species. The purpose of the analytical part of this study was to verify the concentrations of the test item in the test medium.

Guidelines:

Commission Regulation (EC) No 440/2008, Annex, Part C, C.2.: "Daphnia sp. Acute Immobilisation Test", Official Journal of the European Union (EN), dated May 30, 2008

OECD Guideline for Testing of Chemicals No. 202: "Daphnia sp., Acute Immobilisation Test" adopted April 13, 2004

OECD Series on Testing and Assessment, No. 23, "Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures", December 15, 2000

SANCO/3029/99 rev.4 11/07/00: Residues: Guidance for generating and reporting methods of analysis in support of pre-registration data requirements for Annex II (part A; Section 4) and Annex III (part A; Section 5) of directive 91/414

Materials and Methods

Test Item: PETMA; batch no.: 0061491; purity: 96.9 %, according to certificate of analysis

Test Species: Female Daphnia magna, clone 5; 5.75 to 22.75 hours old

Source: The daphnids introduced in the test were taken from ibacon's in-house laboratory culture.

Test Design: This study encompassed 6 treatment groups (5 dose rates of the test item and a control) each containing 20 individuals. The mobility of the daphnids was determined in a semi-static 48-hour test by visual observation after 24 and 48 hours.

Endpoints: Number of immobile organisms after 24 and 48 hours

Test Concentrations:

Due to the low limit of water solubility of the test item, a filtrate of nominal 100 mg/L and dilutions of 1:2, 1:4, 1:8 and 1:16 of this filtrate were tested. Additionally, a control was tested in parallel.

This filtrate and its dilutions correspond to the following geometric mean measured concentrations of the test item:

1.06, 0.390, 0.178, 0.0564 and 0.0392 mg test item/L, and a control.

Test Conditions: Water temperature: 20.4 to 21.5 °C; pH value: 7.8 to 8.1; dissolved oxygen concentration: 5.7 to 8.9 mg/L; photoperiod: 16 h light - 8 h dark; light intensity: 350 to 600 lux; and thus were within the ranges requested by guideline OECD 202

Results

Biological test results:

After 48 hours of exposure no immobilisation of the test animals was observed in the control and all test concentrations up to a geometric mean measured concentration of 1.06 mg test item/L.

The 48-hour NOEC was determined to be ≥ 1.06 mg test item/L. The 48-hour LOEC was determined to be > 1.06 mg test item/L and the 48-hour EC50 value was calculated to be > 1.06 mg test item/L.

Analytical test results:

The quantification of the test item PETMA in the test samples was performed using liquid chromatography with UV detection.

In the freshly prepared test media at the start of the test and at the renewal of the test media 2 % of the nominal test concentrations were found (average of all test concentrations). In the aged test media after 24 and 48 hours test duration, 0.2 % of the nominal value was determined (average of all test concentrations).

During the test the test organism were exposed to a mean of 1.3 % of nominal.

Conclusion:

The toxic effect of the test item PETMA to Daphnia magna was assessed in a semi-static concentration-response test. The 48-hour NOEC was determined to be ≥ 1.06 mg test item/L. The 48-hour LOEC was determined to be > 1.06 mg test item/L and the 48-hour EC50 value was calculated to be > 1.06 mg test item/L.

The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to geometric mean concentrations, since the test item concentrations were not within ± 20 % of the measured initial concentrations during the test. This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

Description of key information

The measured EC50 of PETMA against Daphnia magna is >1.06 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.06 mg/L