Reaction products of 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid, coupled twice with diazotized 2-[(4-aminophenyl)sulfonyl]ethyl hydrogen sulfate, sodium salts

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:

1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

ETAD Ecological Method No. 105. A screening test for assessing the primary anaerobic biodegradability of water-soluble dyestuffs

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
NA

Oxygen conditions:

anaerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Preparation of the Anaerobic Sludge Inoculum:
This is obtained either from the digester of a sewage treatment works operating the heated sludge digestion process and treating predominantly domestic waste, or from a laboratory operated digester fed to a specified protocol with activated sludge and yeast extract.
In either case the sludge is kept warm (35 +/- 2 °C) in a nearly full, loosely stoppered, container for a maximum of 5 days before use, and the dry sludge solids determined by drying aliquots to constant weight.

Sludge concentration: 200 mg/L

Duration of test (contact time):

42 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

Apparatus
A set of identical glass bottles of known capacity in the range 0.5 +/- 0.2 litre is required. Each bottle should be fitted with a magnetic stirring bar, be sealed by a valve such that any gases given off may escape, and have a neck of dimensions such that a dissolved oxygen electrode can be introduced. Three such bottles are required for each dye to be tested plus a further three bottles for the dyestuff which is used as a positive control. An incubator or waterbath with capacity for the bottles and set at 35 +/- 2°C is also required.

Preparation of the test medium:
The test medium is freshly prepared as follows using inorganic chemicals of analytical quality:

Ammonium sulphate: 0.15 g
Monopotassium phosphate:0.10 g
Disodium phosphate: 0.90 g
Magnesium sulphate: 0.02 g
Calcium chloride: 0.01 g
Yeast extract: 0.003 g
Glucose: 0.005 g
Casein: 0.003 g
Distilled water: 1 litre
Immediately prior to the test the medium is warmed to 35 +/- 1 °C.

Value:

81

Sampling time:

42 d

Remarks on result:

other: Decolorization

Details on results:

The % decolourisation reported is the average of results from the seven participating laboratories. The and range is 72 % to 100 % decolorization

Results with reference substance:

dyestuff: 92 % decolorization (89 % - 100 %)

81 % decoloration at 580 nm; sludge concentration: 200 mg/l

Validity criteria fulfilled:

yes

Conclusions:

81 % decolorization of the test item

Executive summary:

The paper describes a method for measuring the primary biodegradability of water soluble dyestuffs under anaerobic conditions and gives the results obtained on 22 dyes of commercial significance.

Reference 2

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

Deviations:

yes

Remarks:

see below

Principles of method if other than guideline:

Deviations from OECD 302 B:
concentration of dyestuff: 100 mg/l; concentration of activated sludge: 0.5 g/l dry material; feeding of the inoculum: each week 100 mg/l yeast extract (in most cases); test duration: up to 42 days; analytical methods: extinction at absorption maximum and DOC (dissolved organic carbon); initial DOC concentration: calculated from stock solution measurement

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

These treatment plants received communal and/or industrial wastewater.

Duration of test (contact time):

28 d

Initial conc.:

13 mg/L

Parameter followed for biodegradation estimation:

DOC removal

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

28 d

Details on results:

9 % adsorption after 3 h (DOC- and photometricdetermination at 580 nm)

Validity criteria fulfilled:

not specified

Interpretation of results:

not inherently biodegradable

Conclusions:

not biodegradable, but 60 % color elimination after 28 days

Executive summary:

A study was conducted according to OECD guideline 302B to evaluate the biodegradation potential of the test substance. The results of the study indicate that the test substance is not biodegradable, but 60% color elimination was noted after 28 days.

DOC start [mg/L]	DOC ads [%]	DOC elim [%]	DOC cat	col ads [%]	col elim [%]	col cat	elim cal	lambda [nm]	time [d]
13	9	-53	D	9	60	B	-	580	28

Description of key information

The test substance is not readily biodegradable in a screening test on biodegradation in water. 

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

In a study conducted according to OECD guideline 302B demonstrated the test substance to be not biodegradable, but 60 % color elimination was noted after 28 days. In a similar screening test at the end of 22 days 81% decolorization of the test item was observed.

In conclusion, screening tests for biodegradation of the test substance in water showed that the test substance is not readily biodegradable.