Nickel, 5-[2-(2-hydroxy-3,7-disulfo-1-naphthalenyl)diazenyl]-1H-1,2,4-triazole-3-carboxylate sodium complexes

Biodegradation in water: screening tests

Administrative data

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:

other: Meets the criteria for classification as Reliable without restriction according to Klimisch et al (1997)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Test Guideline 301F, Ready biodegradability: Manometric respirometry.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

443-510-2

EC Name:

-

Cas Number:

738587-10-5

Molecular formula:

C26H14N10Ni2O18S4 as free acid

IUPAC Name:

dinickel(2+) sodium 3-carboxy-5-[(1E)-2-(7-oxido-2,6-disulfonaphthalen-1-yl)diazen-1-yl]-1H-1,2,4-triazol-1-ide 3-carboxy-5-[(1E)-2-(7-oxido-2-sulfo-6-sulfonatonaphthalen-1-yl)diazen-1-yl]-1H-1,2,4-triazol-1-ide

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Activated sludge was obtained from Buckland Sewage Treatment Works, Newton Abbot, Devon, UK on 31 October 2002. This works treats sewage of predominantly domestic origin. At the laboratory, the activated sludge was kept aerated at room temperature and the pH maintained at 7.0 ± 1.0.

Six days prior to the test the activated sludge was centrifuged, washed and resuspended in the test medium and the solids concentration determined. This sludge was then diluted in medium, added to test bottles and stirred until required for use.

Duration of test (contact time):

28 d

Details on study design:

The test was conducted using activated sludge obtained from a local sewage treatment works as the inoculum.

Triplicate test substance bottles and control (inoculum blanks), together with six positive control bottles (sodium acetate), were prepared. The experimental design consisted of two types of control: inoculum blanks and abiotic controls (poisoned flasks). The former contained viable organisms with no test susbtance or reference substance, the purpose of which was to demonstrate that there was no other carbon source in the test medium. The abiotic controls contained test substance as well as the activated sludge, however the sludge organisms were killed by the addition of HgCI2. The purpose of these controls was to ensure that test substance was present in a medium that has the same amount of particulate matter as the test bottles, so that any removal mechanisms (eg adsorption) or physical degradation (eg hydrolysis) could be accounted for.

The units containing test susbstance were dosed from a primary stock solution containing 1000 mg/l of test substance in deionised water prepared on the exposure start day. Oxygen uptake was recorded on weekdays during the 28 day experimental period. Oxygen uptake values were corrected for the inoculum blank. The biodegradation was calculated as a percentage of the measured chemical oxygen demand for the test or reference substance, as appropriate.

The pH of the test medium prior to use was measured and adjusted as necessary to 7.4 ± 0.2. The pH in several bottles was measured on day 0. The pH in all of the test bottles was measured on day 28. The study was performed in a constant temperature room to maintain the test bottle temperatures within the nominal range of 22 ± 2°C.

Reference substance

Reference substance:

other: Sodium acetate

Results and discussion

Preliminary study:

None conducted.

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

< 10

Sampling time:

5 d

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

< 10

Sampling time:

11 d

% Degradation 3

Parameter:

% degradation (O2 consumption)

Value:

< 10

Sampling time:

15 d

% Degradation 4

Parameter:

% degradation (O2 consumption)

Value:

< 10

Sampling time:

20 d

% Degradation 5

Parameter:

% degradation (O2 consumption)

Value:

< 10

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

Points of degradation plot (reference substance):
60 % degradation after 5 d
63 % degradation after 10 d
63 % degradation after 15 d
63 % degradation after 20 d
63 % degradation after 28 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

Based on the results of the test, the test substance is considered to be not readily biodegradable.