Reaction products of propane-1,2-diamine with 2-[(2-methylphenoxy)methyl]oxirane

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:

2016-01-08 to 2016-03-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Version / remarks:

1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: The (controlled) activated sludge was supplied by the sewage plant for domestic sewage in Balatonfüred, Hungary, on 06 January 2016 (7 days before the test).
- Preparation of inoculum for exposure: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in isotonic saline solution and again centrifuged. This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 5 g dry material per litre was mixed with test water (see below) and then aerated under test conditions (for 7 days) until use. The pH of the activated sludge inoculum after preparation was 7.62, just before use: 6.87. A pH adjustment of activated sludge inoculum was not performed.
- Preconditioning: Pre-conditioning (06-13 January 2016) consisted of aerating (2 L/minute) activated sludge (in mineral medium, reconstituted water for 7 days at the test temperature (the actual temperature range was 20.5-22.9 °C). During the aeration the cell count of inoculum was checked as follows: the viability of the cultured sludge was determined by plating 0.1 mL of the different, usually 10-2, 10-3 and 10-4 dilutions of cultures on nutrient agar plates.
- Initial cell/biomass concentration: On the day of the test this inoculum was diluted adequately with reconstituted water to reach the necessary cell concentration (guideline proposal of 104-106 approx. cells/L).

Duration of test (contact time):

28 d

Initial conc.:

3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: According to OECD guideline
- Test temperature: 20.0-20.4 °C.
- pH: 7.22
- pH adjusted: no
- Aeration of dilution water: yes
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Winkler bottles (300 mL, coded) with special neck and glass stoppers.
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Pre-conditioning (06-13 January 2016) consisted of aerating (2 L/minute) activated sludge (in mineral medium, reconstituted water) for 7 days at the test temperature.
- Measuring equipment: The oxygen concentration was measured with an O2 electrode [working based on LDO (Luminescent Dissolved Oxygen) method].

SAMPLING
- Sampling frequency: Analysed on the 7th, 21st and 28th day of the test.
- Sampling method: 5 mL sample was measured into the reaction cell. The cell was closed tightly and was shaken vigorously until the reagent was completely dissolved.
- Sample storage before analysis: The 0-day and 14-day samples were taken after the oxygen concentration measurements, but these samples were stored for 7 days before the measurements in refrigerator until a later determination.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes, 3 mg/L test and 3 mg/L reference item

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

8.4

Sampling time:

28 d

Details on results:

Under the test conditions the percentage biodegradation of SIKA Amine PC (SIKA Amin PC) reached a mean of 8.4 % after 28 days based on its calculated ThODNH4. The biodegradation reached its plateau on the 7th day and from this the variations, slight changes were considered as being within the biological variability range of the applied test system. The test item was considered to be not ready biodegradable.
In the toxicity control containing both, the test item and the reference item, a mean of 35.5 % biodegradation was noted within 14 days and a mean of 37.1 % biodegradation was determined after 28 days of incubation.

Results with reference substance:

The reference item Sodium benzoate was sufficiently degraded to a mean of 72.4 % after 14 days, and to a mean of 83.8 % after 28 days of incubation, based on ThODNH4

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test item was considered to be not ready biodegradable. According to the test guidelines the pass level for ready biodegradability is 60 % of ThODNH4.
According to the test guidelines the test item can be assumed as not inhibitory on the activated sludge microorganisms because the degradation in the toxicity control group was higher than 25 % within 14 days.
The percentage biodegradation of the reference item confirms the suitability of the used activated sludge inoculum.

Executive summary:

The purpose of this study was to determine the ready biodegradability of the test item SIKA Amine PC (SIKA Amin PC). The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The test item SIKA Amine PC (SIKA Amin PC) was investigated at the concentration of 3.0 mg/L. The concentration was chosen based on the preliminary test results and based on the theoretical oxygen demand of 2.15 mg O2/mg test item (ThODNH4, calculated according to equation given in the guidelines, assuming that no nitrification occurs). In parallel (under the same conditions as the test item), positive reference item, sodium benzoate at the concentration of 3.0 mg/L (as procedure control), inoculum control and toxicity control were investigated. All validity criteria of the study were met. Under the test conditions ready biodegradation of this test item was not noticed. The percentage biodegradation of SIKA Amine PC (SIKA Amin PC) reached a mean of 8.4 % after 28 days based on its ThODNH4.

The parallel running analytical determination of a possible nitrite and nitrate development demonstrated that no nitrification occurred, therefore the biodegradability of the test item was calculated based on its ThODNH4; any correction, based on the nitrite and/or nitrate content was not performed. The reference item sodium benzoate was sufficiently degraded to a mean of 72.4 % after 14 days, and to a mean of 83.8 % after 28 days of incubation, based on ThODNH4. In the toxicity control containing both, the test item and the reference item, a mean of 35.5 % biodegradation was noted within 14 days and 37.1 % biodegradation after 28 days of incubation. The test item is considered to be not ready biodegradable, since the pass level for ready biodegradability is removal of 60% ThODNH4 in a 10-day window. The percentage biodegradation of the reference item confirms the suitability of the used activated sludge inoculum. According to the test guidelines the test item can be assumed as not inhibitory at the applied concentration level on the activated sludge microorganisms because the degradation in the toxicity control group was higher than 25 % within 14 days.

Description of key information

The ready biodegradation was tested in a study with the test item according to guidelines. Under test conditions no biodegradation was observed.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The purpose of this study was to determine the ready biodegradability of the test item. The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The test item was investigated at the concentration of 3.0 mg/L. The concentration was chosen based on the preliminary test results and based on the theoretical oxygen demand of 2.15 mg O2/mg test item (ThODNH4, calculated according to equation given in the guidelines, assuming that no nitrification occurs). In parallel (under the same conditions as the test item), positive reference item, sodium benzoate at the concentration of 3.0 mg/L (as procedure control), inoculum control and toxicity control were investigated. All validity criteria of the study were met. Under the test conditions ready biodegradation of this test item was not noticed. The percentage biodegradation of the test item reached a mean of 8.4 % after 28 days based on its ThODNH4.

The parallel running analytical determination of a possible nitrite and nitrate development demonstrated that no nitrification occurred, therefore the biodegradability of the test item was calculated based on its ThODNH4; any correction, based on the nitrite and/or nitrate content was not performed. The reference item sodium benzoate was sufficiently degraded to a mean of 72.4 % after 14 days, and to a mean of 83.8 % after 28 days of incubation, based on ThODNH4. In the toxicity control containing both, the test item and the reference item, a mean of 35.5 % biodegradation was noted within 14 days and 37.1 % biodegradation after 28 days of incubation. The test item is considered to be not ready biodegradable, since the pass level for ready biodegradability is removal of 60% ThODNH4 in a 10-day window. The percentage biodegradation of the reference item confirms the suitability of the used activated sludge inoculum. According to the test guidelines the test item can be assumed as not inhibitory at the applied concentration level on the activated sludge microorganisms because the degradation in the toxicity control group was higher than 25 % within 14 days.