Ammonium 2-(acryloylamino)-2-methylpropane-1-sulfonate

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:

March-October, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

ammonium (1Z)-N-(2-methyl-1-sulfopropan-2-yl)prop-2-enimidate

EC Number:

611-646-3

Cas Number:

58374-69-9

Molecular formula:

C7H12NO4S.H4N

IUPAC Name:

ammonium (1Z)-N-(2-methyl-1-sulfopropan-2-yl)prop-2-enimidate

Test material form:

liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

125 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The study was performed using aerobic activated sludge from BRIANZACQUE civil wastewater treatment plant. The sludge were collected on March 23, 2016. An homogenized aliquot of the wet sludge was centrifuged, the supernatant was removed while the solid phase was weighed, dried and the ratio of wet to dry weight was calculated to be equal to10.95 %.

Based on this ratio, calculated amounts of wet sludge was centrifuged, the supernatant was removed and the solid phase was suspended in the test medium to get a concentration equivalent to 3 g dry material per litre.

The prepared sludge inoculum was pre-conditioned to the experimental conditions by aerating it in the dark. The concentrated suspension was used as inoculum to give a final concentration of 15 mg dry material per litre into test flasks.

Since the test item was fully soluble in water, a concentrated stock solution at 200.0 mg/L was prepared by weighing 0.2000 g of test item in 1000 mL of mineral medium.
The proper volume was dosed in the test flasks to obtain the final concentrations of 125.0 mg/L of test item making to a final volume of 250 mL or 150 mL (based on setting scale) with test medium (see Table 1).

Moreover, stock solutions (10.0 g/L) of reference item Sodium Benzoate and sterilizing agent HgCl2 were prepared and an appropriate aliquot of the stock solution was added to the test medium (final volume: 250 mL or 150 mL ) in the test flasks to obtain a final concentration of 100.0 mg/L.

Activated sludge was added to each flask (with the exception of the abiotic control) before incubation.

Finally, the test flasks, containing stir bars covered with teflon, were kept under continuous stirring by the means of a magnetic stirrer for the 28-days test period.

In Table 1, number of replicates, scale setting, volume added and concentration of sterilizing agent and test/reference item is shown.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

2.8

Sampling time:

28 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item, 2-Acrylamido-2-methylpropanesulfonic acid, ammonium salt, was found to be not ready and completely biodegradable under the conditions applied in a manometric respirometry test, having showed a maximum biodegradation of 2.8 % during the test period (mean percentage values between two replicates) at the end of the test period.

No significant degradation was observed in the abiotic control.

Moreover, the test item showed no inhibitory effects on the microorganism activity at the tested concentration, as demonstrated by the biodegradation percentage in the toxicity control exceeding the 25 % pass level after one day of exposure (34.8%).