1,2-Benzenediol, 4-[(4-methylphenyl)sulfonyl]-

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
[Please provide information for all of the points below. Indicate if further information is included as attachment to the same record, or elsewhere in the dataset (insert links in 'Cross-reference' table)]

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
[Describe why the read-across can be performed (e.g. common functional group(s), common precursor(s)/breakdown product(s) or common mechanism(s) of action]

See attached documents.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
[Provide here, if relevant, additional information to that included in the Test material section of the source and target records]
See attached documents.


3. ANALOGUE APPROACH JUSTIFICATION
[Summarise here based on available experimental data how these results verify that the read-across is justified]
See attached documents.

4. DATA MATRIX
See attached documents.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

2019

Deviations:

no

GLP compliance:

yes

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

79.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

79.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortality or symptoms of distress were observed in the control and the three lowest test concentrations throughout the exposure period. All fish exposed to the highest test concentration were observed dead after 24 hours of exposure.

Validity criteria fulfilled:

yes

Conclusions:

The 96h-LC50 was 79.6 mg/L based on read-across from a structural analogue.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

2019

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control according to the schedule below.
Frequency at t=0 h and t=24 h (highest test concentration) or t=96 h (control and four lowest test concentrations)
Volume 4.0 mL from the approximate centre of the test vessels.
Storage Samples were stored in a freezer (≤-15°C) until analysis at the analytical laboratory of the Test Facility.

Additionally, reserve samples of 4.0 mL were taken from all test solutions for possible analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The batch of CH03951 tested was an off-white powder with a purity of approximately
96.85 w/w%. No correction was made for the purity/composition of the test item.
For the saturation test, a loading rate of 100 mg/L was prepared and continuously stirred for three days while samples for possible chemical analysis were taken approximately every 24 hours.
For the range-finding and final tests, preparation of test solutions started with a loading rate of 100 mg/L applying a fifteen-minute period of ultrasonic waves followed by a three-day period of magnetic stirring to ensure maximum dissolution of the test item in test medium. Thereafter, 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):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: Carp
- Source: Zodiac, proefacc, "De Haar Vissen", Wageningen University and Research Centre, The Netherlands.
- Age at study initiation (mean and range, SD): /
- Length at study initiation (length definition, mean, range and SD):
Range-finding test: 2.7 ± 0.2 cm
Final test: 2.9 ± 0.2 cm
- Weight at study initiation (mean and range, SD):
Range-finding test: 0.25 ± 0.08 g
Final test: 0.30 ± 0.07 g
- Method of breeding: /

ACCLIMATION
- Acclimation period: At least 12 days after delivery
- Acclimation conditions (same as test or not): Adjusted ISO medium, formulated using RO-water (tap-water purified by reverse osmosis; GEON Waterbehandeling, Berkel- Enschot, The Netherlands) with the following composition:
CaCl2.2H2O 211.5 mg/L
MgSO4.7H2O 88.8 mg/L
NaHCO3 46.7 mg/L
KCl 4.2 mg/L
- Type and amount of food during acclimation: Daily with pelleted fish food (F-0.5 GR Pro Aqua Brut, Skretting, Fontaine-lès-Vervins, France) until at the latest 24 hours before the start of exposure
- Health during acclimation (any mortality observed): In the batch of fish used for the test, mortality during the seven days prior to the start of the test was less than 5%.

FEEDING DURING TEST
No feeding from 24 hours prior to the test and during the total test period

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test temperature:

T: 20-22°C

pH:

7.4-8.1, constant within 1 unit

Dissolved oxygen:

oxygen > 60% of air saturation (>6.8 mg/L)

Nominal and measured concentrations:

nominal: 10, 18, 32, 56 and 100% of the SS prepared at a loading rate of 100 mg/L
The measured concentrations at the start of the test were 10, 19, 32, 58 and 101 mg/L, respectively, in solutions containing 10, 18, 32, 56 and 100% of the SS prepared at a loading rate of 100 mg/L. During the exposure period, the concentrations remained stable, i.e. were at 97-103% relative to the initial concentrations at the end of the applicable test duration, i.e. for the solution containing 100% of the SS after 24 hours of exposure and the remaining test concentrations after 96 hours of exposure. It was concluded that the undissolved fraction removed during the preparation of test solutions had not been test item related.

Details on test conditions:

TEST SYSTEM
6.5 litres, all-glass, containing 5 litres of test solution
- Aeration: AAeration was introduced in the afternoon of Day 2 of exposure
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.42 g fish/litre, i.e.7 fish per 5 litres of test medium


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours photoperiod daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
- Test concentrations: 5 (10, 18, 32, 56 and 100% of the SS prepared at a loading rate of 100 mg/L. )

Reference substance (positive control):

yes

Remarks:

Reference test with pentachlorophenol (PCP) in February 2017

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

75 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

75 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortality or symptoms of distress were observed in the control and the three lowest test concentrations throughout the exposure period. All fish exposed to the highest test concentration were observed dead after 24 hours of exposure.

Reported statistics and error estimates:

95%-confidence interval: 56 – 100 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The 96h-LC50 was 75 mg/L (95% confidence interval between 56 and 100 mg/L) based on analytically confirmed nominal exposure concentrations and was already reached after 24 hours of exposure.

Executive summary:

The objective of the study was to evaluate CH03951 for its ability to generate acute toxic effects inCyprinus carpioduring an exposure period of 96 hours and, if possible, to determine the LC₅₀at all observation times.

A full test was performed based on the results of a range-finding test. The study met the validity criteria prescribed by the study plan. Test conditions and results of the final test are presented in the table below:

Test Item:	CH03951
Appearance:	Off white powder
Purity:	Approximately 96.85% w/w%
Preparation of test solutions:	Saturated Solution (SS), loading rate of 100 mg/L. Lower concentrations: serial dilution.
Experimental Set-up
Guideline(s)	OECD TG 203 (2019) and OECD GD 23 (2019)
Exposure design:	Static, no renewals
Test concentration(s):	Solutions containing 10, 18, 32, 56 and 100% of the SS
Control	Blank control
Number of specimens	Seven fish for the control and per test concentration
Sampling for analysis	At t=0 h and t=24 h (highest test concentration) or t=96 h (control and four lowest test concentrations)
Experimental conditions
pH, Temperature, Dissolved Oxygen	Within the ranges specified in OECD TG 203
Light regime	A daily photoperiod of 16 hours with a light intensity ranging between 548-756 lux
Results
Actual exposure concentrations	10, 19, 32, 58 and 101 mg/L (analytically confirmed nominal concentrations)
Recorded effects	No mortality or symptoms of distress were observed in the control and the three lowest test concentrations throughout the exposure period. All fish exposed to the highest test concentration were observed dead after 24 hours of exposure.

The effect parameters (based on analytically confirmed nominal concentrations) obtained in this study are summarized in the table below.

Parameter	CH03951 Nominal conc. (mg/L)	95%-confidence interval
24, 48, 72 and 96h-LC50	75	56 – 100

Description of key information

Based on read-across from a structural analogue, the LC50 for fish was 76.9 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

76.9 mg/L