Calcium 3-hydroxy-4-[(1-sulphonato-2-naphthyl)azo]-2-naphthoate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

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)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: aerobic activated sludge from a wastewater treatment treating predominantly domestic wastewater
- Preparation of inoculum for exposure: Sludge was washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated.
Based on this ratio, calculated amounts of wet sludge were suspended in test water to obtain a concentration equivalent to 4 g (±10%) dry material per liter. During the holding period of one day prior to use, the sludge was aerated at room temperature. Prior to use, the sludge was diluted with test water to a concentration of about 1 g dry material per liter. Defined volumes of this diluted activated sludge were added to test water to obtain a final concentration of 30 mg dry material per liter.

Duration of test (contact time):

28 d

Initial conc.:

33 mg/L

Based on:

test mat.

Initial conc.:

15.3 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: One day before test start (Day-1), between 2400 and 3000 mL of untreated test medium was filled into the flasks and 90 ml activated sludge inoculum was added. Then aeration overnight with CO2-free air on the following day (Day 0), defined amounts of the test item were directly added to the test flasks and made up to a volume of 3 L with test water.
- Solubilising agent: none
- Test temperature: 21-23 °C
- pH: 7.2 - 7.4
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 5-liter all-glass amber bottles
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Air was led through a bottle containing about 750 ml of a 2 M NaOH solution to trap CO2. The CO2-free air was passed through the test solutions at a rate corresponding to about 30-100 ml/min.
- Details of trap for CO2 and volatile organics if used: Two absorber flasks, the first one containing 300 ml 0.05 M NaOH and the second one
containing 200 ml 0.05 M NaOH, were connected in series to the exit air line of each test flask.

SAMPLING
- Sampling frequency:
- Test item and inoculum control: 2, 5, 7, 9, 12, 14, 19, 23, 27, 28, 29
- Procedure control: 2, 7, 14, 28, 29
- Toxicity control: 7, 14, 28, 29
- Sampling method: aliquot of 5.0 ml withdrawn from the absorber flask nearest to the test flask for analysis of inorganic carbon

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 replicates
- Toxicity control: 1 replicate
- Procedure control: 2 replicates

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

Results with reference substance:

Mean degradation rate after 28 days = 77.1%

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test item is not readily biodegradable (by OECD criteria). It is poorly biodegradable.

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

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]

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]

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

4. DATA MATRIX

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

read-across: supporting information

Key result

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

Validity criteria fulfilled:

not applicable

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Based on the test results of the source substance PR 48:2 and two different QSARs run on PR 63:1, the test item is considered not readily biodegradable.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable method, meets basic scientific principles

Justification for type of information:

QSAR prediction

Qualifier:

according to guideline

Guideline:

other: CATALOGIC 301C model for predicting biodegradability of chemicals (CATALOGIC 301C v.08.11)

Principles of method if other than guideline:

Estimation of results of OECD screening tests on ready biodegradation in water: CATALOGIC (v5.11.16) BOD 28 days MITI (OECD 301C) v08.11

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

Model domain similarity:
- Parametric domain: 100%
- Structural domain: 63.33% (36.67% unknown)
- Mechanistic domain: 100%

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test item is not readily biodegradable (by OECD criteria). It is poorly biodegradable.

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Accepted calculation method

Justification for type of information:

QSAR prediction

Qualifier:

according to guideline

Guideline:

other: Estimation of Aerobic Biodegradability using BIOWIN v4.10 (EPI Suite v4.11): BIOWIN1 to BIOWIN6 and Ready Biodegradability Prediction

Principles of method if other than guideline:

Prediction of ready biodegradability based on six QSAR models

GLP compliance:

no

Oxygen conditions:

aerobic

Duration of test (contact time):

28 d

Parameter:

other: bidegradation

Sampling time:

28 d

Remarks on result:

other: Results: Not readily biodegradable

BIOWIN v4.10 Results

 

Biowin1 (Linear Model Prediction) : Does Not Biodegrade Fast

Biowin2 (Non-Linear Model Prediction): Does Not Biodegrade Fast

Biowin3 (Ultimate Biodegradation Timeframe): Months

Biowin4 (Primary Biodegradation Timeframe): Weeks

Biowin5 (MITI Linear Model Prediction) : Does Not Biodegrade Fast

Biowin6 (MITI Non-Linear Model Prediction): Does Not Biodegrade Fast

Biowin7 (Anaerobic Model Prediction): Does Not Biodegrade Fast

Ready Biodegradability Prediction: NO

 

TYPE	NUM	Biowin1 FRAGMENT DESCRIPTION	COEFF	VALUE
Frag	1	Aromatic alcohol [-OH]	0.1158	0.1158
Frag	1	Azo group [-N=N-]	-0.2418	-0.2418
MolWt	*	Molecular Weight Parameter		-0.2192
Const	*	Equation Constant		0.7475
RESULT	Biowin1 (Linear Biodeg Probability)			0.4023

 

TYPE	NUM	Biowin2 FRAGMENT DESCRIPTION	COEFF	VALUE
Frag	1	Aromatic alcohol [-OH]	0.9086	0.9086
Frag	1	Azo group [-N=N-]	-8.2194	-8.2194
MolWt	*	Molecular Weight Parameter		-6.5388
RESULT	Biowin2 (Non-Linear Biodeg Probability)			0.0000

 

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast

A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

 

TYPE	NUM	Biowin3 FRAGMENT DESCRIPTION	COEFF	VALUE
Frag	1	Aromatic alcohol [-OH]	0.0564	0.0564
Frag	1	Azo group [-N=N-]	-0.3004	-0.3004
MolWt	*	Molecular Weight Parameter		-1.0176
Const	*	Equation Constant		3.1992
RESULT	Biowin3 (Survey Model - Ultimate Biodeg)			1.9376

 

TYPE	NUM	Biowin4 FRAGMENT DESCRIPTION	COEFF	VALUE
Frag	1	Aromatic alcohol [-OH]	0.0397	0.0397
Frag	1	Azo group [-N=N-]	-0.0528	-0.0528
MolWt	*	Molecular Weight Parameter		-0.6644
Const	*	Equation Constant		3.8477
RESULT	Biowin4 (Survey Model - Primary Biodeg)			3.1703

 

Result Classification: 5.00 -> hours 4.00 -> days 3.00 -> weeks

(Primary & Ultimate) 2.00 -> months 1.00 -> longer

 

TYPE	NUM	Biowin5 FRAGMENT DESCRIPTION	COEFF	VALUE
Frag	1	Aromatic alcohol [-OH]	0.0642	0.0642
Frag	1	Azo group [-N=N-]	-0.0459	-0.0459
Frag	11	Aromatic-H	0.0082	0.0904
MolWt	*	Molecular Weight Parameter		-1.3699
Const	*	Equation Constant		0.7121
RESULT	Biowin5 (MITI Linear Biodeg Probability)			-0.5490

 

 

TYPE	NUM	Biowin6 FRAGMENT DESCRIPTION	COEFF	VALUE
Frag	1	Aromatic alcohol [-OH]	0.4884	0.4884
Frag	1	Azo group [-N=N-]	-10.6129	-10.6129
Frag	11	Aromatic-H	0.1201	1.3216
MolWt	*	Molecular Weight Parameter		-13.2934
RESULT	Biowin6 (MITI Non-Linear Biodeg Probability)			0.0000

 

A Probability Greater Than or Equal to 0.5 indicates --> Readily Degradable

A Probability Less Than 0.5 indicates --> NOT Readily Degradable

 

TYPE	NUM	Biowin7 FRAGMENT DESCRIPTION	COEFF	VALUE
Frag	1	Aromatic alcohol [-OH]	0.0807	0.0807
Frag	1	Azo group [-N=N-]	0.0000	0.0000
Frag	11	Aromatic-H	-0.0954	-1.0497
Const	*	Equation Constant		0.8361
RESULT	Biowin7 (Anaerobic Linear Biodeg Prob)			-0.1329

 

 

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast

A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

 

Ready Biodegradability Prediction: (YES or NO)

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

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 (see Help). Biowin5 and 6 also predict ready biodegradability, but for degradation in the OECD301C test only; using data from the Chemicals Evaluation and Research Institute Japan (CERIJ) database.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test item is not readily biodegradable (by OECD criteria). It is poorly biodegradable.

Description of key information

Studies on biodegradation of the test substance are not available. However, two QSAR calculations have been conducted (BASF SE 2014 and 2015). Both EPISuite BIOWIN v4.10 and CATALOGIC v5.11.16 (BOD 28 days MITI (OECD 301C) v06.07) showed that the test substance is not readily biodegradable according OECD criteria. The test substance is within the applicability domain of both QSAR models. Even though for CATALOGIC the structural domain was correct with only 63.33 % (unknown 36.67 %) the results support the overall conclusion in the weight-of-evidence.

The QSAR calculation results are supported by the results of a study on biodegradability of the read-across substance (CAS 7023-61-2; BASF SE 2007). The read-across justification is attached in chapter 13. In the test following OECD guideline 301B the ready biodegradability of the read-across substance was tested. Based on the CO2 evolution a degradation rate of 0 % was determined after 28 days inoculation time.

Therefore, in overall conclusion, it can be stated that the test substance in not readily biodegradable according OECD criteria.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

  According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

For the assessment of the test substance (Q)SAR results were used for aerobic biodegradability in water. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

Therefore, further experimental studies on aerobic biodegradability in water are not provided.