3-[(aminoiminomethyl)thio]propanesulphonic acid

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

adopted 17. Jul. 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

adopted 30. May 2008

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: SOP 118 00 615 "Abbaubarkeit nach OECD 301F"

Version / remarks:

edition 6 valid from 25. Apr. 2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Kaiser-Friedrich-Straße 7, 55116 Mainz, Germany

Test material

Test material information

Constituent 1

Reference substance name:

3-[(aminoiminomethyl)thio]propanesulphonic acid

EC Number:

244-520-8

EC Name:

3-[(aminoiminomethyl)thio]propanesulphonic acid

Cas Number:

21668-81-5

Molecular formula:

C4H10N2O3S2

IUPAC Name:

3-(carbamimidoylsulfanyl)propane-1-sulfonic acid

Test material form:

solid: particulate/powder

Details on test material:

Storage: Room Temperature (20 ± 5°C), keep away from humidity

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge from a biologic sewage treatment plant was used as inoculum. The chosen plant is treating mostly household sewage. The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf.
- Pretreatment: The sludge was filtrated, washed with tap water 2x, then washed with and resuspended in test medium. It was then aerated.
The dry matter was determined as 4780 mg suspended solids/L.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

59 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

61.93 mg/L

Based on:

ThOD

Remarks:

without nitrification

Initial test substance concentration 3

Initial conc.:

100.07 mg/L

Based on:

ThOD

Remarks:

with nitrification to nitrate

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium:
Stock solutions
a) 8.5 g KH2PO4, 21.75 g K2HPO4, 33.4 g Na2HPO4 x 2 H2O, 0.5 g NH4Cl and 1000 mL H2O demin. ad
b) 27.5 g CaCl2 x 2H2O and 1000 mL H2O demin. ad
c) 22.5 g MgSO4 x 7H2O and 1000 mL H2O demin. ad
d) 0.25 g FeCl3 x 6H2O, 0.4 g Na2EDTA x 2H2O and 1000 mL H2O demin. ad
Test Medium
10 mL solution a
1 mL solution b
1 mL solution c
1 mL solution d
1000 mL H2O demin. ad
- Test temperature: 21.4 - 22.2 °C
- pH: 7.2 (abiotic test vessel), 7.4 (other vessels)
- pH adjusted: yes (in abiotic test vessel only)
- Suspended solids concentration: 24.9 mg/L

TEST SYSTEM
- Number of culture flasks/concentration: 3 (test item, medium and inoculum)
- Other:
Volume of test vessels: 500 mL
Volume test solution: 250 mL (toxicity control flask 125 mL)

CONTROL AND BLANK SYSTEM
- Inoculum blank: 3 (medium and inoculum)
- Abiotic sterile control: 1 (test item and 10 mL 1% HgCl2 solution)
- Toxicity control: 1 (200 mg/L ThOD, 100 mg/L ThOD each of test item and positive control)
- Other: Number of positive control vessels: 3 (sodium benzoate, medium and inoculum)

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

No observations were made which might cause doubts concerning the validity of the study outcome.

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

Degradation after 3 days > 60% (validity criterion fulfilled)
Positive control 1: 72.4 % degradation after 28 days
Positive control 2: 78.2 % degradation after 28 days
Positive control 3: 81.2 % degradation after 28 days

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The study was performed according to OECD TG301F and EU Method C.4-D (GLP) without any deviations and therefore considered to be of the highest quality (reliability Klimisch 1). The validity criteria of the test system are fulfilled. Within 28 days, no degradation (0%) was determined for the test substance. Therefore, the test substance is considered to be not readily biodegradable.

Executive summary:

The biodegradability of the test substance was investigated according to EU method C.4 -D and OECD guideline 301 F (GLP). A measured volume of inoculated mineral medium, containing the test item in a concentration of 59 mg/L (corresponding to a ThOD of 100.07 mg O2/L), was stirred in a closed flask at a constant temperature for up to 28 days. Activated sludge from a biologic sewage treatment plant was used as inoculum. The chosen plant is treating mostly household sewage. Analytical grade salts were added to deionised water to prepare the stock solutions. Sodium benzoate was used as positive control. Also a toxicity control (test item and positive control mixed) and an abiotic control (test item and 10 mL 1% HgCL2 solution/L) was run in parallel, to ensure, that the chosen test concentration was not inhibitory to microorganims. The degradation rate of the test item was calculated by the oxygen consumption of the aerobic activated sludge microorganisms after 28 days of incubation.

Oxygen consumption in the blank controls and in the positive controls was normal, indicating that the test system has worked properly.

Ready biodegradability is defined in the guidelines as degradation surpassing 60% within 10 days after reaching a level of 10%. No degradation was observed within the test duration of 28 days. Therefore, the test item 3-[(Amino-iminomethyl)-thio]-1-propanesulphonic acid can be considered as “not readily biodegradable”.

If degradation in the toxicity flask is below 25% after 14 days, the test item can be considered as toxic towards the inoculum. As degradation in the toxicity flask was 36.4 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 59 mg/L”.

No observations were made which might cause doubts concerning the validity of the study outcome.

The result of the test can be considered valid.