Bis(2-hydroxyethyl) sulphone

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:

The study was conducted between 25 July 2016 and 13 September 2016

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)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identification: BHES
Physical state/Appearance: White solid block
Batch: 160226
Purity: 99.64%
Expiry Date: 01 March 2017
Storage Conditions: Room temperature in the dark

Analytical monitoring:

yes

Details on sampling:

Range finding test:
Concentrations - 0.10, 1.0, 10 and 100 mg/L
A sample of each test concentration was taken for chemical analysis at 0 and 48 hours in order to determine the stability of the test item under test conditions. All samples were stored frozen prior to analysis. Only concentrations within the range to be used for the definitive test were analyzed.


Definitive test
Concentrations - 100 mg/L
Samples were taken from the control and the 100 mg/L test group from the bulk test preparation at 0 hours and from the pooled replicates at 48 hours for quantitative analysis. All samples were stored frozen prior to analysis. 
Duplicate samples were taken and stored frozen for further analysis if necessary.

Vehicle:

no

Details on test solutions:

Range finding test:
A nominal amount of test item (50 mg) was dissolved in test water and the volume adjusted to 500 mL to give the 100 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 0.10, 1.0 and 10 mg/L. Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.

Definitive test:
A nominal amount of test item (100 mg) was dissolved in test water and the volume adjusted to 1 liter to give the 100 mg/L test concentration.
The prepared concentration was inverted several times to ensure adequate mixing and homogeneity.

Test organisms (species):

Daphnia magna

Details on test organisms:

The test was carried out using 1st instar Daphnia magna derived from in-house laboratory cultures.
Adult daphnia were maintained in 150 mL glass beakers containing Elendt M7 medium in a temperature controlled room maintaining the water temperature at 18 to 22 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods. Each culture was fed daily with a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension. Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

18 to 22 °C

pH:

7.9 - 8.6

Dissolved oxygen:

5.3 - 8.7 mg/L

Nominal and measured concentrations:

Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to be near nominal and so the results are based on nominal test concentrations.
Concentrations were as follows:
Range finding test: 0.10, 1.0, 10 and 100 mg/L.
Definitive test: 100 mg/L

Details on test conditions:

Range-finding Test
In the range-finding test 10 daphnids were placed in each test and control vessel and maintained in a temperature controlled room maintaining the water temperature at 18 to 22 °C with a maximum deviation of ±1 °C with a photoperiod of 16 hours light and 8 hours darkness for a period of 48 hours with 20 minute dawn and dusk transition periods. Each 150 mL test and control vessel contained 100 mL of test media and was covered to reduce evaporation. After 24 and 48 hours the number of immobilized daphnids were recorded.
The control group was maintained under identical conditions but not exposed to the test item.

Definitive Test
Based on the results of the range-finding test a "Limit test" was conducted at a concentration of 100 mg/L to confirm that at the maximum concentration given in the OECD/EC Test Guidelines, no immobilization or adverse reactions to exposure were observed.
As in the range-finding test 150 mL glass beakers containing approximately 100 mL of test preparation were used. At the start of the test 5 daphnids were placed in each test and control vessel at random, in the test preparations. Four replicate test and control vessels were prepared. The test vessels were then covered to reduce evaporation and maintained in a temperature controlled room maintaining the water temperature at 18 to 22 °C with a maximum deviation of ±1 °C with a photoperiod of 16 hours light (between 200 and 1200 Lux) and 8 hours darkness with 20 minute dawn and dusk transition periods. The daphnids were not individually identified, received no food during exposure and the test vessels were not aerated.
The control group was maintained under identical conditions but not exposed to the test item.
The test preparations were not renewed during the exposure period.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

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:

Range-finding Test
No immobilization was observed at the test concentrations of 0.10, 1.0, 10 and 100 mg/L.
Based on this information, a single test concentration of four replicates, of 100 mg/L was selected for the definitive test. This experimental design conforms to a "Limit test" to confirm that at the maximum test concentration given in the OECD/EC Test Guidelines, no immobilization or adverse reactions to exposure were observed.
Chemical analysis of the 100 mg/L test preparation at 0 hours showed the measured test concentration to be 108% of nominal the concentration. There was no significant change in the measured concentration at 48 hours indicating that the test item was stable under test conditions.

Definitive Test
Immobilization Data
There was no immobilization in 20 daphnids exposed to a test concentration of 100 mg/L for a period of 48 hours.
Exposure of Daphnia magna to the test item gave EC50 values of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.
It was considered unnecessary and unrealistic to test at concentrations in excess of 100 mg/L.

Sub-Lethal Effects
No sub-lethal effects of exposure were observed throughout the test.

Results with reference substance (positive control):

A positive control (Envigo Study Number MS29MC) used potassium dichromate as the reference item at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L.

Exposure conditions for the positive control were similar to those in the definitive test.

Results at 24 hrs were as follows:
EC50 - 0.83 mg/L (0.70 - 0.98 mg/L)
NOEC - 0.56 mg/L
LOEC - 1.0 mg/L

Results at 48 hrs were as follows:
EC50 - 0.64 mg/L (could not determine 95% confidence limits)
NOEC - 0.56 mg/L
LOEC - 1.0 mg/L

The results from the positive control with potassium dichromate were within normal range for this reference item.

Validation Criteria

The test was considered to be valid given that none of the control daphnids showed immobilization or other signs of disease or stress and that the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

The method of analysis was validated and proven to be suitable for use.

Water Quality Criteria

Temperature was maintained at 19 °C to 22 °C throughout the test, while there were no treatment related differences for oxygen concentration or pH.

Throughout the test the light intensity was observed to be in the range 534 to 540 Lux.

Observations on Test Item Solubility

At the start and throughout the test all control and test solutions were observed to be clear colorless solutions.

Cumulative Immobilization Data and Observations in the Range-finding Test are presented in the following table:

Nominal Concentration (mg/L)	Observations (Initial Population: 10 Per Replicate)
	24 Hours		48 Hours
	Cumulative Immobilized Daphnia	Observations	Cumulative Immobilized Daphnia	Observations
Control	0	10 N	0	10 N
0.10	0	10 N	0	10 N
1.0	0	10 N	0	10 N
10	0	10 N	0	10 N
100	0	10 N	0	10 N

N = No sub-lethal effects observed

Cumulative Immobilization Data and Observations in the Definitive Test are presented in the following tables:

Nominal Concentration (mg/L)	24 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4
Control	0	0	0	0	0	0	5 N	5 N	5 N	5 N
100	0	0	0	0	0	0	5 N	5 N	5 N	5 N

Nominal Concentration (mg/L)	48 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4
Control	0	0	0	0	0	0	5 N	5 N	5 N	5 N
100	0	0	0	0	0	0	5 N	5 N	5 N	5 N

R₁– R₄= Replicates 1 to 4

N = No sub-lethal effects observed

Water Quality Measurements are presented in the table below

Nominal Concentration (mg/L)		0 Hours			24 Hours	48 Hours
		pH	mg O2/L	T°C	T ºC	pH	mg O2/L	T°C
Control	R1	8.0	5.3	19	20	8.0	8.7	22
100	R1	7.9	5.8	20	20	8.0	8.6	22

R₁= Replicate 1

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EC50 value of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.

Executive summary:

Introduction

A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Methods

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at a concentration of 100 mg/L for 48 hours at a temperature of 19°C to 22°C under static test conditions. Immobilization and any adverse reactions to exposure were recorded after 24 and 48 hours.

Results…….

Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to be near nominal and so the results are based on nominal test concentrations.

Exposure of Daphnia magna to the test item gave EC₅₀ values of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.

It was considered unnecessary and unrealistic to test at concentrations in excess of 100 mg/L.

Description of key information

Introduction

A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphniasp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Methods

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at a concentration of 100 mg/L for 48 hours at a temperature of 19°C to 22°C under static test conditions. Immobilization and any adverse reactions to exposure were recorded after 24 and 48 hours.

Results…….

Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to be near nominal and so the results are based on nominal test concentrations.

Exposure of Daphnia magna to the test item gave EC₅₀values of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.

It was considered unnecessary and unrealistic to test at concentrations in excess of 100 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L