Bis(2-hydroxyethyl) sulphone

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 01 Agust 2016 and 13 September 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

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:
A sample of each test concentration was taken for chemical analysis at 0 and 24 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:
Water samples were taken from the control and each test group at 0 and 72 hours from fresh media and at 24 and 96 hours from old media for quantitative analysis. All samples were stored frozen prior to analysis.
Duplicate samples and samples at 24 (fresh media), 48 (old and fresh media) and 72 hours (old media) were taken and stored frozen for further analysis if necessary.

Vehicle:

no

Details on test solutions:

Range finding test:
In the range-finding test fish were exposed to a series of nominal test concentrations of 1.0, 10 and 100 mg/L.
A nominal amount of test item (4000 mg) was dissolved in test water and the volume adjusted to 1 liter to give the 4000 mg/L stock solution from which a series of dilutions was made to give the required test concentrations of 1.0, 10 and 100 mg/L.
The stock solution was inverted several times and the test concentrations were stirred for approximately 1 minute with a flat bladed mixer to ensure adequate mixing and homogeneity.

Definitive test:
Based on the results of the range-finding test the following test concentrations were assigned to the definitive test: 10, 18, 32, 56 and 100 mg/L.
A nominal amount of test item (8000 mg) was dissolved in test water and the volume adjusted to 2 liters to give the 4000 mg/L stock solution. Aliquots (50, 90, 160, 280 and 500 mL) were taken and the volume adjusted to 20 liters to produce the 10, 18, 32, 56 and 100 mg/L test concentrations.
The stock solution was inverted several times and the test concentrations were stirred for approximately 1 minute with a flat bladed mixer to ensure adequate mixing and homogeneity.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

The test was carried out using juvenile rainbow trout (Oncorhynchus mykiss). Fish were obtained from Brow Well Fisheries Limited, Hebden, near Skipton, Yorkshire, UK and maintained in house since 16 August 2016. Fish were maintained in a glass fiber tank with a "single pass" water renewal system. Fish were acclimatized to test conditions from 28 August 2016 to 05 September 2016. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods.
The water temperature was controlled at 14 °C with a dissolved oxygen content of greater than or equal to 8.9 mg O2/L. These parameters were recorded daily. The stock fish were fed commercial trout pellets which was discontinued approximately 23 hours prior to the start of the definitive test. There was no mortality in the 7 days prior to the start of the test and the fish had a mean standard length of 5.0 cm (sd = 0.58) and a mean weight of 1.0 g (sd = 0.41) at the end of the definitive test. Based on the mean weight value this gave a loading rate of 0.35 g bodyweight/liter (static volume).
The diet and diluent water are considered not to contain any contaminant that would affect the integrity and outcome of the study.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

140 mg/L as CaCO3

Test temperature:

11 °C to 14 °C

pH:

7.6 - 8.3

Dissolved oxygen:

8.3 - 10.7 mg O2/L

Nominal and measured concentrations:

Analysis of the test preparations at 0, 24 and 96 hours showed measured test concentrations to be near nominal and so it was considered justifiable to calculate the LC50 values in terms of the nominal test concentrations only.
Concentrations were as follows:
Range finding test - 1.0, 10 and 100 mg/L.
Definitive test - 10, 18, 32, 56 and 100 mg/L.

Details on test conditions:

Range finding test:
In the range-finding test three fish were placed in each test and control vessel and maintained in a temperature controlled room at 13 °C to 14 °C with a photoperiod of 16 hours light and
8 hours darkness with 20 minute dawn and dusk transition periods for a period of 96 hours under static test conditions. Each 25-30 liter test and control vessel contained 20 liters of test media and was covered to reduce evaporation. After 1, 3, 6, 24, 48, 72 and 96 hours any mortalities or sub-lethal effects of exposure were determined by visual inspection of the test fish.
The control group was maintained under identical conditions but not exposed to the test item.

Defintive test:
As in the range-finding test, 25-30 liter glass exposure vessels containing 20 liters of test media were used for each control and test concentration. At the start of the test seven fish were placed in each test vessel at random, in the test preparations. The test vessels were then covered to reduce evaporation and maintained at 11 °C to 14 °C in a temperature controlled room with a photoperiod of 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods for a period of 96 hours. The test vessels were aerated via narrow bore glass tubes. The fish were not individually identified and received no food during exposure.
The control group was maintained under identical conditions but not exposed to the test item.
A semi-static test regime was employed in the test involving a daily renewal of the test preparations to prevent the buildup of nitrogenous waste products.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Range finding test:
The results showed no mortalities at the test concentrations of 1.0 and 10 mg/L. However, one mortality was observed at 100 mg/L after 24 hrs.
Based on this information test concentrations of 10, 18, 32, 56 and 100 mg/L were selected for the definitive test.
Chemical analysis of the test preparations at 0 and 24 hours showed near nominal concentrations were obtained, indicating that the test item was stable under test conditions.

Definitive test:
Mortality Data:
There were no mortalities in 7 fish exposed to test concentrations of 10, 18, 32 and 100 mg/L for a period of 96 hours. However, there was mortality in 1 out of 7 fish exposed to a test concentration of 56 mg/L at 96 hrs.
Exposure of rainbow trout (Oncorhynchus mykiss) to the test item gave LC50 values based on the nominal test concentrations of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.

Sub-Lethal Effects:
There were no sub-lethal effects of exposure observed in the test.

Sublethal observations / clinical signs:

Validation Criteria

The test was considered to be valid given that none of the control fish died or showed signs of stress during the test and that the oxygen concentration at the end of the test was ≥60% of ASV (6.1 mg O2/L) in the control and test vessels.

Water Quality Criteria

Temperature was maintained at 11 °C to 14 °C throughout the test, while there were no treatment related differences for oxygen concentration or pH.

Some of the temperatures were measured to be slightly in excess of the 13 °C to 17 °C given in the study plan. This was considered not to affect the results of the test as no adverse effects of exposure were observed throughout the duration of the test.

 Observations on Test Item Solubility

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

Cumulative mortality data in the definitive test is presented in the table below:

Nominal Concentration (mg/L)	Cumulative Mortality (Initial Population = 7)						Percentage Mortality
	3 Hours	6 Hours	24 Hours	48 Hours	72 Hours	96 Hours	96 Hours
Control	0	0	0	0	0	0	0
10	0	0	0	0	0	0	0
18	0	0	0	0	0	0	0
32	0	0	0	0	0	0	0
56	0	0	0	0	0	1	14
100	0	0	0	0	0	0	0

Sub-lethal effects of exposure in the definitive test are presented in the following table:

Nominal Concentration (mg/L)	Sub-lethal Effects	Time (Hours)
		3	6	24	48	72	96
Control	No abnormalities detected	7	7	7	7	7	7
10	No abnormalities detected	7	7	7	7	7	7
18	No abnormalities detected	7	7	7	7	7	7
32	No abnormalities detected	7	7	7	7	7	7
56	No abnormalities detected	7	7	7	7	7	6
100	No abnormalities detected	7	7	7	7	7	7

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater fish rainbow trout (Oncorhynchus mykiss) has been investigated and based on the nominal test concentrations gave a 96-Hour LC50 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 rainbow trout (Oncorhynchus mykiss). The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.1 of Commission Regulation (EC) No. 440/2008.

Methods

Following a preliminary range-finding test, fish were exposed, in groups of seven, to an aqueous solution of the test item over a range of concentrations of 10, 18, 32, 56, 100 mg/L for a period of 96 hours at a temperature of approximately 11°C to 14 °C under semi-static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 1, 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.

Results…….

Analysis of the test preparations at 0, 24 and 96 hours showed measured test concentrations to be near nominal and so the results are based on nominal test concentrations only.

Exposure of rainbow trout (Oncorhynchus mykiss) to the test item gave LC₅₀values based on the nominal test concentrations of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.

Description of key information

Introduction

A study was performed to assess the acute toxicity of the test item to rainbow trout (Oncorhynchus mykiss). The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.1 of Commission Regulation (EC) No. 440/2008.

Methods

Following a preliminary range-finding test, fish were exposed, in groups of seven, to an aqueous solution of the test item over a range of concentrations of 10, 18, 32, 56, 100 mg/L for a period of 96 hours at a temperature of approximately 11°C to 14 °C under semi-static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 1, 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.

Results…….

Analysis of the test preparations at 0, 24 and 96 hours showed measured test concentrations to be near nominal and so the results are based on nominal test concentrations only.

Exposure of rainbow trout (Oncorhynchus mykiss) to the test item gave LC₅₀values based on the nominal test concentrations of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

100 mg/L