1-Naphthalenesulfonic acid, 3-diazo-3,4-dihydro-4-oxo-, ester with phenyl(2,3,4-trihydroxyphenyl)methanone 6-diazo-5,6-dihydro-5-oxo-1-naphthalenesulfonate

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

Study period:

5. June to 3. July, 1992

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)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Duration of test (contact time):

28 d

Initial conc.:

60.9 mg/L

Based on:

test mat.

Remarks:

39.65 mg as carbon

Initial conc.:

32.6 mg/L

Based on:

test mat.

Remarks:

21.22 mg as carbon

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The test substance was directly weighed into the test vessels (5L glass vessels)

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

< 20

Sampling time:

28 d

The degradation of the reference substance caused CO2-formation amounting to more than 60 % of the theoretical maximum within 10 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test substance was found to be not readily biodegradable.

Executive summary:

The testing according to the modified Sturm test (OECD Guideline 301 B) revealed that the test item was not readily biodegradable. Within a period of 28 days the CO2 formation stayed below 20 % of the theoretical maximum.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Substances whose physicochemical, toxicological and ecotoxicological properties are likely
to be similar as a result of structural similarity may be considered as analogue substances.
In this case, experimental data of one substance may provide indications for the (eco-)
toxicological profile of another, based on a read-across approach.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source and target substances have similar
properties based on structural similarity and because they degrade to a common product and
non-common products are predicted to have no toxicological effects. For the REACH
information requirement under consideration, the property investigated in a study conducted
with the source substance is used to predict the properties that would be observed in a study
with the target substance if it were to be conducted.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Both substances are organic and share comparable molecular structures. They share the
carbon -6-ring structures, diazo-groups and sulfonate ester bonds. Both substances are esters and produced by addition and substitution reactions. Furthermire, the target substance is an UVCB substance (please refer to IUCLID section 1 for a description of the manufacturing process). The result of the manufacturing process is a reaction product of all possible mono, di , tri esters of TOB (2,3,4-Trihydroxybenzophenone) with F6 and FF (sulfonyl chloride is substituted). The esterification can happen in any position and, for di/tri-esters in any combination (homo- or hetero-esters). The source substance itself is a tetraester and contains the triester CAS 105935-62-4 as well as the biester CAS 114571-69-6 as impurities, with an ester distribution of 78-90 %
tetraester/10-20 % triest/2 %diester. Further impurities are unknown or only present at concentrations below 1 %.

3. ANALOGUE APPROACH JUSTIFICATION
Based on the structural similarieties biotransformation will most probably occur via similar pathways and the products are considered to be very similar and at least partly the same.
As no biodegradation was observed in the study conducted with the source substance, this is also anticipated for the target substance. As this result is also reflecting a worst-case scenario, read-across is considered acceptable.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Key result

Parameter:

% degradation (CO2 evolution)

Value:

< 20

Sampling time:

28 d

Details on results:

The degradation of the reference substance caused CO2-formation amounting to more than 60 % of the theoretical maximum within 10 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The source substance was found to be not readily biodegradable.

Executive summary:

The testing according to the modified Sturm test (OECD Guideline 301 B) revealed that the test item was not readily biodegradable. Within a period of 28 days the CO2 formation stayed below 20 % of the theoretical maximum.

Description of key information

The substance was considered to be not readily biodegradable based on structural similarity with the read-across substance and applying a worst-case approach. 

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

No data is available for the substance itself. Based on the structure of the substance and applying a worst case-approach, it was considered to be not biodegradable. This assumption is supported by read-across, based on structural similarity with a source substance. This source substance was tested according to the modified Sturm test (OECD Guideline 301 B), the study revealed that the test item was not readily biodegradable. Within a period of 28 days the CO2 formation stayed below 20 % of the theoretical maximum.