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

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
EpiSuite

2. MODEL (incl. version number)
BIOWIN v 4.10

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
c1(O)c(O)cc(S(=O)(=O)c2ccc(C)cc2)cc1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
[Explain how the model fulfils the OECD principles for (Q)SAR model validation. Consider attaching the QMRF or providing a link]
See QMRF

5. APPLICABILITY DOMAIN
[Explain how the substance falls within the applicability domain of the model]
See QPRF

6. ADEQUACY OF THE RESULT
[Explain how the prediction fits the purpose of classification and labelling and/or risk assessment]
The QSAR prediction is used to determine the biodegradability of the substance. This information is required to assess the PBT classification.

Qualifier:

according to guideline

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

BIOWIN: Estimates aerobic and anaerobic biodegradability of organic chemicals using 7 different models. Two of these are the original Biodegradation Probability Program (BPP™). The seventh and newest model estimates anaerobic biodegradation potential.

Specific details on test material used for the study:

c1(O)c(O)cc(S(=O)(=O)c2ccc(C)cc2)cc1

Remarks on result:

not readily biodegradable based on QSAR/QSPR prediction

 

 

Type	Num	Biowin 5 Fragment description	Coeff	Value
Frag	2	Aromatic alcohol (-OH)	0.0642	0.0642
Frag	1	Aromatic-CH3	0.0415	0.0415
Frag	7	Aromatic-H	0.0082	0.0740
MolWt	*	Molecular Weight Parameter		-0.7863
Const	*	Equation constant		0.7121
Results				0.1533

 

A probability greater than or equal to 0.5 indicates ‘readily biodegradable’

A probability less than to 0.5 indicates ‘NOT readily biodegradable’

----------------------------------------------

 Criteria for the YES or NO prediction: If the Biowin3 (ultimate survey model) result is "weeks" or faster (i.e. "days", "days to weeks", or "weeks" AND the Biowin5 (MITI linear model) probability is >= 0.5, then the prediction is YES (readily biodegradable). If this condition is not satisfied, the prediction is NO (not readily biodegradable). This method

is based on application of Bayesian analysis to ready biodegradation data.

Validity criteria fulfilled:

not applicable

Interpretation of results:

not readily biodegradable

Conclusions:

The substance is not biodegradable according to BIOWIN.

Executive summary:

QPRF:BIOWIN v4.10(20 May 2014)

 

1.	Substance	See “Test material identity”
2.	General information
2.1	Date of QPRF	See “Data Source (Reference)”
2.2	QPRF author and contact details	See “Data Source (Reference)”
3.	Prediction
3.1	Endpoint (OECD Principle 1)	Endpoint	Biodegradation
3.2	Algorithm (OECD Principle 2)	Model or submodel name	BIOWIN
		Model version	v. 4.10
		Predicted value (model result)	See “Results and discussion”
		Input for prediction	- Chemical structure via CAS number
		Descriptor values	- MITI Linear Model Prediction - Correction factors
3.3	Applicability domain (OECD principle 3)	Domains:
		1) Molecular weight (range of test data set: 30.02 to 959.2 g/mol; On-Line BIOWIN User’s Guide, Ch. 7 Domain)		Substance within range (264.30 g/mol)
		2) Correction factors: Number of instances of the identified correction factor does not exceed the maximum number as listed in Appendix D (On-Line BIOWIN User’s Guide)		Fulfilled.
3.4	The uncertainty of the prediction (OECD principle 4)	Statistical accuracy for training dataset: n = 589, R2= 0.823 Statistical accuracy for validation dataset: n = 295, R2= 0.813
3.5	The chemical mechanisms according to the model underpinning the predicted result (OECD principle 5)	Biowin 5 is a predictive model for assessing a compound’s biodegradability in the Japanese MITI (Ministry of International Trade and Industry) ready biodegradation test: i.e. OECD 301C. A journal article giving a complete description of the MITI biodegradation models has been published (Tunkel et al. 2000).

 

References

- US EPA (2012). On-Line BIOWIN User’s Guide.

- Tunkel J, Howard PH, Boethling RS, Stiteler W, Loonen H. 2000. Predicting Ready Biodegradability in the Japanese Ministry of International Trade and Industry Test. Environ. Chem. 19: 2478-2485.

 

 

Assessment of estimation domain (molecular weight, fragments, correction factors):

 

Appendix D. Fragment Coefficients for biodegradation model

Correction Factor Descriptor	MITI biodegradability coefficients	Occurrence		No. of instances of each bond found for the current substance
		(number of compounds	(max per structure)
Aromatic alcohol (-OH)	0.0642	65	2	2
Aromatic-CH3	0.0415	49	3	1
Aromatic-H	0.0082	302	15	7

 

 

 

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

weight of evidence

Study period:

2019-2020

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 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

Adopted July 17, 1992

Deviations:

no

GLP compliance:

yes

Test performance:

The pH values stayed between 7.4 and 7.8.
The temperature recorded in a vessel with Milli-RO water in the same room varied between 22 and 23°C, and complied with the requirements as laid down in the study plan.

Parameter:

% degradation (CO2 evolution)

Value:

23

Sampling time:

21 d

Details on results:

Relative biodegradation values calculated from measurements performed during the test period revealed 23 % biodegradation of CH03951 (based on ThCO2) in both vessels. Thus, the criterion for ready biodegradability (at least 60 % biodegradation within a 10-day window) was not met.

In the toxicity control, 59 % biodegradation was observed. Therefore, CH03951 was found not to inhibit microbial activity at a concentration of 11 mg/L.
Functioning of the test system was checked by testing the procedural control item sodium acetate, which showed a normal biodegradation curve

Results with reference substance:

Procedural control item was biodegraded by at least 60 % (actual result: 75 % in) within 14 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Based on read-across from a structural analogue (CH03951), CH04008 was not considered readily biodegradable.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019-2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

Adopted July 17, 1992

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Effluent freshly obtained from a municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage
- Laboratory culture: /
- Method of cultivation: /
- Storage conditions: The filtrate was kept aerated until inoculation.
- Storage length: /
- Preparation of inoculum for exposure: /
- Pretreatment: /
- Concentration of sludge: 4 mL filtrate of secondary effluent per litre of final volume.
- Initial cell/biomass concentration: /
- Water filtered: yes
- Type and size of filter used, if any: Secondary effluent was filtered through a coarse filter paper, the first 200 mL were discarded.

Duration of test (contact time):

28 d

Initial conc.:

21 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Test duration 28 days for the inoculum blank and test suspension
14 days for the procedure and toxicity control
Test bottles 2 litre brown coloured glass bottles
Milli-RO water Tap-water purified by reverse osmosis (Millipore Corp., Bedford, Mass., USA).

Stock solutions of mineral components
A) 8.50 g KH2PO4
21.75 g K2HPO4
67.20 g Na2HPO4.12H2O
0.50 g NH4Cl
dissolved in 1 litre Milli-RO water, pH 7.4 + 0.2
B) 22.50 g MgSO4.7H2O dissolved in 1 litre Milli-RO water.
C) 36.40 g CaCl2.2H2O dissolved in 1 litre Milli-RO water.
D) 0.25 g FeCl3.6H2O dissolved in 1 litre Milli-RO water.

Mineral medium 1 mL aliquots of solution (A) to (D) were mixed and made up to 1 litre with Milli-RO water. T
Barium hydroxide 0.0125 M Ba(OH)2 (Boom, Meppel, The Netherlands), stored in a sealed vessel to prevent absorption of CO2 from air.
Pre-incubation medium Before the start of the test (Day -1) mineral components, Milli- RO water (ca. 80 % of final volume) and inoculum were added to each bottle. This mixture was aerated with synthetic air overnight to purge the system of CO2.
Type and number of bottles Test suspension: containing test item and inoculum (2 bottles).
Inoculum blank: containing only inoculum (2 bottles)
Procedural control: containing procedural control item and inoculum (1 bottle).
Toxicity control: containing test item, procedural control item and inoculum (1 bottle).
Illumination The test bottles were protected from light.
Preparation At the start of the test (Day 0), test and procedural control item were added to bottles containing microbial organisms and mineral components.
Volumes were made up to 2 L with Milli- RO water, resulting in the mineral medium described before.
Three CO2-absorbers (bottles filled with 100 mL 0.0125 M Ba(OH)2) were connected in series to the exit aeration line of each test bottle.

Reference substance:

other: sodium acetate

Test performance:

The pH values stayed between 7.4 and 7.8.
The temperature recorded in a vessel with Milli-RO water in the same room varied between 22 and 23°C, and complied with the requirements as laid down in the study plan.

Parameter:

% degradation (CO2 evolution)

Value:

23

Sampling time:

21 d

Details on results:

Relative biodegradation values calculated from measurements performed during the test period revealed 23 % biodegradation of CH03951 (based on ThCO2) in both vessels. Thus, the criterion for ready biodegradability (at least 60 % biodegradation within a 10-day window) was not met.

In the toxicity control, 59 % biodegradation was observed. Therefore, CH03951 was found not to inhibit microbial activity at a concentration of 11 mg/L.
Functioning of the test system was checked by testing the procedural control item sodium acetate, which showed a normal biodegradation curve

Results with reference substance:

Procedural control item was biodegraded by at least 60 % (actual result: 75 % in) within 14 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

In conclusion, CH03951 was designated as not readily biodegradable.

Executive summary:

The objectiveofthe studywas to evaluate test item CH03951 for its ready biodegradability in an aerobic aqueous medium with microbial activity introduced by inoculation with activated sludge.

Procedures described in this report were in compliance with OECD guideline No. 301 B, 1992. In addition, procedures were designed to meet test methods of ISO standard 10634, 2018.

In total, two experiments were performed. In the first experiment a potentially inhibitory effect was found in the toxicity control. Therefore, a second experiment was performed at a 50 % decreased concentration.

CH03951 was an off-white powderwith a purity of approximately 96.85 w/w%. Test item was tested in duplicate at a concentration of 11 mg/L, corresponding to 6 mg TOC/L. Organic carbon content was based on the molecular formula. Theoretical CO₂ production (ThCO₂) of CH03951 was calculated to be 2.12 mg CO₂/mg.

The study consisted of six bottles:

·     2 inoculum blanks (no test item),

·     2 test bottles (CH03951),

·     1 procedural control (sodium acetate) and

·     1 toxicity control (CH03951 plus sodium acetate).

Since CH03951 was not sufficiently soluble to allow preparation of an aqueous stock solution at a concentration of 1 g/L, weighed amounts were added to 2 L test bottles containing medium with microbial organisms and mineral components. To this end, approximately 10 mL of Milli- RO water was added to each weighing bottle containing test item. After vigorous mixing (vortex) the resulting suspension was added quantitatively to the test medium. Test solutions were continuously stirred during the test, to ensure optimal contact between test item and test organisms. Furthermore, test medium was swirled around daily, since the test item tended to float on the water surface.Test duration was28 days for inoculum blank and test item (last CO₂measurement on Day 29) and 14 days for procedural and toxicity control (last CO₂measurement on Day 15).

Relative biodegradation values calculated from measurements performed during the test period revealed 23 % biodegradation of CH03951 (based on ThCO₂) in both vessels. Thus, the criterion for ready biodegradability (at least 60 % biodegradation within a 10-day window) was not met.

In the toxicity control, CH03951 was found not to inhibit microbial activity at a concentration of 11 mg/L.

Since all criteria for acceptability of the test were met, this study was considered to be valid.

In conclusion,CH03951 was designated as not readily biodegradable.

Description of key information

Based on QSAR result (BIOWIN) and read-across from a structural analogue, the substance is considered not to be biodegradable. 

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater