Diphenyl sulphone

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2021-2022

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

GLP compliance:

yes

Specific details on test material used for the study:

Identification: Diphenyl sulphone
Batch (Lot) Number: 202011220005
Expiry date: 22 November 2022 (retest date)
Physical Description: White crystalline
Purity/Composition: 99.99%
Storage Conditions: At room temperature
Test concentrations were not corrected for the purity of the test substance.

Analytical monitoring:

yes

Details on sampling:

Sampling scheme
Fresh solutions: day 0, 1 and 3

Old solutions: day 1, 3 and 6
Sampled groups Samples were taken from all groups but also from an extra vessel incubated under the same conditions, but without daphnia and algae (abiotic control). The abiotic control was included in order to assess the effect of biota on the exposure concentrations.

Observations
Survival
Presence of eggs in the brood pouch
Number of offspring
Number of aborted eggs

Measurements of temperature, pH, and dissolved oxygen At the start and at the end of the exposure. In addition, in both fresh and old medium at each renewal.

Samples for analysis were taken from all test concentrations and the control according to the schedule below.
Frequency
1. At the start of the test and weekly thereafter from the freshly prepared solutions (day 7 and 16).
2. At the first renewal (day 2) and weekly thereafter from the 48-hour (day 9) or 72-hour old solutions (day 19).

Volume 1.4 mL
Storage Samples were stored in a freezer (set to maintain -20°C) until analysis at the analytical laboratory of the Test Facility.
At the end of the renewal period, the replicates were pooled at each concentration before sampling.

Additionally, reserve samples of 1.4 mL were taken from all test solutions for possible analysis. If not already used, these samples were stored in a freezer (set to maintain -20°C) for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.

Vehicle:

no

Details on test solutions:

The batch of Diphenyl sulphone tested was a white crystalline with a purity of 99.99% and not completely soluble in test medium at the loading rate initially prepared. No correction was made for the purity/composition of the test substance.
Preparation of test solutions started with a loading rate of 100 mg/L applying a three-day period of magnetic stirring to ensure maximum dissolution of the test item in medium. In the range-finding, a period of 15 minutes ultrasonication was applied prior to the three-day period of magnetic stirring. Subsequently, the aqueous Saturated Solution (SS) was collected by filtration through a 0.45 µm membrane filter (RC55, Whatman) and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS in test medium. All test solutions were clear and colorless at the end of the preparation procedure.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species
Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
Source
In-house laboratory culture with a known history.
Reason for selection This system has been selected as an internationally accepted invertebrate species.
Validity of batch
Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discolored animals and there was no delay in the production of the first brood.
Characteristics To initiate the test, young daphnids < 24 hours old were selected.

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

21 d

Hardness:

> 140 mg/L (as CaCO3)

Test temperature:

18-22°C, constant within 2°C

pH:

Between 6.0 to 9.0, constant within 1.5 units

Dissolved oxygen:

> 3 mg/L

Details on test conditions:

Samples taken from all test concentrations and the control were analyzed. The measured concentrations in the freshly prepared solutions upon test commencement were 0.13, 0.42, 1.2, 4.1, 13 and 27 mg/L

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

13 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: parent survival

Key result

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

4.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

1.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.41 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

On average, 174 offspring were produced per surviving daphnid in the control treatment. The number of offspring was similar to the control treatment in all treated groups except for the highest test concentration, where a reduction of 89% was observed.
Statistical analysis showed that the reproduction of the daphnids was significantly reduced at concentrations of 1.1 mg/L and higher The NOEC for reproduction was 0.41 mg/L. The LOEC was 1.1 mg/L .

Validity criteria fulfilled:

yes

Conclusions:

The chronic toxicity of Diphenylsulfone was assessed in a semi static 21 d reproduction test according to OECD 211, using Daphnia magna as test species.
The test substance concentration were analytical verified. Actual exposure concentrations were expressed in terms of Time Weighed Mean (TWM).All validity criteria were fulfilled.After 21 days of exposure a NOEC( reproduction) of 0.41 mg/L was determined.

Executive summary:

In conclusion, under the conditions of the present study Diphenyl sulphone did affect reproduction, growth, and survival of Daphnia magna at concentrations of 0.41 mg/L and higher after 21 days of exposure.

The 21d-EC₁₀ for reproduction was 4.2 mg/L with a 95% confidence interval ranging from 1.3 to 6.2 mg/L and the 21d-EC₅₀ for reproduction was 8.5 mg/L with a 95% confidence interval ranging from 5.4-11 mg/L. The NOEC was 0.41 mg/L based on statistical significance, and the LOEC was 1.1 mg/L.

The NOEC for parental mortality was 13 mg/L, while the LOEC of this endpoint exceeded the highest concentration tested (>13 mg/L).

The 21d-EC₁₀ for parental growth was 8.3 mg/L with a 95% confidence interval ranging from 15 to 24 mg/L. The NOEC was 1.1 mg/L based on statistical significance, and the LOEC was 4.2 mg/L.

The NOEC for age at first reproduction was 4.2 mg/L, and the LOEC was 13 mg/L.

The 21d-EC₁₀ for immobile offspring was 6.6 mg/L with a 95% confidence interval ranging from 4.2 to 10 mg/L. The NOEC was 4.2 mg/L based on statistical significance, and the LOEC was 13 mg/L.

Description of key information

The chronic  toxicity  of Diphenylsulfone  was assessed in a  semi static  21 d reproduction test according to OECD 211, using Daphnia magna as test species.
The test substance concentration were analytical verified. Actual exposure concentrations were expressed in terms of  Time Weighed Mean (TWM).All validity criteria  were  fulfiled.After 21 days of exposure  a NOEC( reproduction) of 0.41 mg/L was determined. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

0.41 mg/L