2,2-dimethylthiazolidine

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted July 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Date of receipt: 2015-03-17
Expiry date: 2017-10-01

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Type: mixed population of aquatic microorganisms
Origin : aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal)
Date of collection : 2016-12-12
Concentration of inoculum : 30 mg/L suspended solids

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Details on study design:

The endogenous activity of the inoculum was checked running parallel blanks with inoculum but without test item. A reference compound (sodium benzoate) was run in parallel to check the operation of the procedures.
A toxicity control (test item and reference compound mixed, one replicate) was run in parallel, to ensure that the chosen concentration of the test item was not inhibitory to microorganisms.
Degradation was followed by the determination of oxygen uptake and measurements were taken at frequent intervals to allow the identification of the beginning and end of biodegradation and the slope of the biodegradation curve.
Because of the nature of biodegradation and of the mixed bacterial populations used as inoculum, determinations of test item and inoculum blank were carried out in triplicate and of reference compound in duplicate.
The oxygen uptake was calculated from the readings taken at regular and frequent intervals, using the method given by the manufacturer of the equipment. At the end of incubation, the pH was measured in the flasks.
The test item is an N-containing substance. Therefore, the concentration of nitrite and nitrate was determined at the start and at the end of the test. The oxygen consumed by nitrification was calculated. This oxygen consumption by nitrification was subtracted from the respective measurements.

Reference substance:

benzoic acid, sodium salt

Remarks:

Purity: 99.9 % Expiry date: 2018-03-27

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

53

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

59

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

63

Sampling time:

28 d

Details on results:

Test concentration: 100 mg/L

Parameter:

BOD5

Value:

152.5 other: mg O2/L

Remarks on result:

other: blank-corrected BOD

Remarks:

The oxygen consumed by nitrification was < 1 mg/L. and no consumption by nitrification was subtracted from the respective 28 days measurements of the test item.

Parameter:

BOD5

Value:

146.5 other: mg O2/L

Remarks on result:

other: blank-corrected BOD

Remarks:

The oxygen consumed by nitrification was < 1 mg/L. and no consumption by nitrification was subtracted from the respective 28 days measurements of the test item.

Parameter:

BOD5

Value:

136.5 other: mg O2/L

Remarks on result:

other: blank-corrected BOD

Remarks:

The oxygen consumed by nitrification was < 1 mg/L. and no consumption by nitrification was subtracted from the respective 28 days measurements of the test item.

Parameter:

ThOD

Value:

2.321 other: mg O2/mg

Results with reference substance:

The reference compound sodium benzoate showed 88 % degradation after 14 days.

Constant temperature of 22 ± 1 °C for 28 days

pH values after 28 days: 7.5 - 8.0

Validity criteria fulfilled:

yes

Remarks:

All validity criteria of the test method were met.

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

Test item 2,2-Dimethylthiazolidin showed 63 % degradation after 28 days and is considered readily biodegradable.

Executive summary:

A study was performed to assess the ready biodegradability of 2,2-Dimethylthiazolidin according to OECD Guideline 301 F.

A suspension of 2,2-Dimethylthiazolidin in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by continuous automated BOD determinations.

2,2-Dimethylthiazolidin showed:

0% degradation after 7 days

53 % degradation after 14 days

59 % degradation after 21 days

63 % degradation after 28 days

Therefore, 2,2-Dimethylthiazolidin is considered to be “Readily Biodegradable“ but failing 10 day window.

Description of key information

A study was performed to assess the ready biodegradability of 2,2-Dimethylthiazolidin according to OECD Guideline 301 F.

A suspension of 2,2-Dimethylthiazolidin in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by continuous automated BOD determinations. 2,2-Dimethylthiazolidin showed 63 % degradation after 28 days.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable but failing 10-day window