Disodium 1,5-dihydroxypentane-1,5-disulphonate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 10 JUL 2017 to 10 AUG 2017

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Version / remarks:

Following OECD 301A resp. EU C.4 - A

Deviations:

no

Remarks:

Principles of method if other than guideline:

Temperature range was 19.5 – 22.2 °C and the samples were stored in the fridge for 72 hours (3.7-7.0°C).
Degradation of the positive control was in the normal range this is considered as uncritical concerning the outcome of the study.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Disodium 1,5-dihydroxypentane-1,5-disulphonate

Cas Number:

7420-89-5

Molecular formula:

C5H10Na2O8S2

IUPAC Name:

Disodium 1,5-dihydroxypentane-1,5-disulphonate

impurity 1

Reference substance name:

Sodium sulfate

Cas Number:

7757-82-6

IUPAC Name:

Sodium sulfate

impurity 2

Reference substance name:

Sodium hydrogen sulfite

Cas Number:

7631-90-5

IUPAC Name:

Sodium hydrogen sulfite

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

other: Activated sludge from a biologic sewage treatment plant was used. The chosen plant treats mostly domestic sewage.

Details on inoculum:

Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L).

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

206.4 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

Aniline was chosen as positive control.

The test item was tested using a concentration of 39.9 mg organic carbon/L (corresponding to 206.4 mg test item Glutardialdehyde bis-Sodiumbisulfite/L) in test medium.

Results and discussion

Preliminary study:

The sludge was filtrated through a clean cotton cloth, then washed with tap water twice, with test medium once and resuspended in test medium. It was then aerated until use in the test. Determination of dry matter gave 3720 mg suspended solids/L.

% Degradation

Key result

Parameter:

% degradation (DOC removal)

Value:

92

Sampling time:

28 d

Remarks on result:

other: The degree of biodegradation reached 92 % after 28 days

Details on results:

The validity criteria were met. Degradation behaviour of positive control and toxicity control was normal. Both replicates of the test item showed very good correspondence. After 9 day a plateau of degradation above 80 % was observed. As degradation in the toxicity flask was 89 % after 14 days, the test item can be stated as not toxic towards the inoculum in a concentration of 206.4 mg/L. A time-delayed reduction of DOC was observed also in the adsorption control and the abiotic control. Abiotic degradation reached 24 % at the end of the test and the adsorption control reached 63 %. This might be caused by adsorption of the test item onto the bacteria in the adsorption control and precipitation of dissolved test item in the abiotic control. No observations were made which might cause doubts concerning the validity of the study outcome. The result of the test can be considered valid.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Difference within replicates at the end was 0.3 % (criterion: ≤ 20 %). Positive control reached the pass level of 70 % on day 6 (98 %) (criterion: > 70 % within 14 d). Total biodegradation in the toxicity control after 14 da was 89 % (criterion: > 35 %)

Interpretation of results:

readily biodegradable

Conclusions:

The 10-day-window began on day 2, at its end, 88 % were reached, surpassing the pass level of 70 % stated in the OECD Guideline. The degree of biodegradation reached 92 % after 28 days. The test item can be considered as „readily biodegradable“.