DL-2-aminopropan-1-ol

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:

26 September 2016 to 18 November 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:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

1

Reference substance name:

DL-2-aminopropan-1-ol

EC Number:

228-207-3

EC Name:

DL-2-aminopropan-1-ol

Cas Number:

6168-72-5

Molecular formula:

C3H9NO

IUPAC Name:

2-aminopropan-1-ol

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Columbia Wastewater Treatment Plant
- Storage conditions: Effluent was aerated and stored at app. 20 Degree Celcius
- Pretreatment: Upon arrival in lab, ap. 1 lit of the secondary effluent that was collected was filtered through glass wool. The first 200mL of filtrate was discarded and remainder was aerated in a 20 degree Celcius environmental chamber until added to the test medium
- Water filtered: yes
- Type and size of filter used, if any: Glass wool

Duration of test (contact time):

29 d

Initial test substance concentration

Initial conc.:

3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The primary objective of this study was to evaluate the aerobic biodegradability of the test substance, RS-12401.00, in water containing mineral salts and the secondary effluent from a wastewater treatment plant (WWTP) as the source of microbial inoculum. The test substance was exposed to the effluent inoculum under aerobic conditions for 29 days at approximately 20°C. A reference substance treatment containing readily biodegradable sodium benzoate at a nominal concentration of 3 mg/L was concurrently tested to verify the viability of the microbial inoculum. A control treatment containing no lest or reference substance was concurrently tested to measure the oxygen uptake caused by endogenous microbial respiration. Two biochemical oxygen demand (BOD) bottles from each treatment were randomly removed after 0, 5, 15, 21, and 29 days of incubation at 20°C and were measured for dissolved oxygen concentration and for pH.
The effluent was obtained from the Columbia Wastewater Treatment Plant in Columbia, Missouri on 22 September 2016. The effluent was aerated and stored at approximately 20°C for 5 days.
Microbial enumeration was performed at Day 0 on the effluent and on one replicate for each treatment at the end of the test to further investigate microbial activity/viability during the testing. These analyses indicated that the microbial inoculum remained viable and active through the end of the test in each treatment.
Percent degradation was calculated by expressing BOD as a percent of theoretical oxygen demand
(ThOD). ThOD was 1.70 mg O2/mg assuming no nitrification, and 2.56 mg O2/mg assuming complete nitrification, calculated based on the elemental composition.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (O2 consumption)

Value:

62.8

Sampling time:

29 d

Remarks on result:

other: Based on ThOD assuming complete nitrification

% Degradation 2

Key result

Parameter:

% degradation (O2 consumption)

Value:

94.5

Sampling time:

29 d

Remarks on result:

other: Based on ThOD assuming no nitrification

BOD5 / COD results

Results with reference substance:

Biodegradation of the reference substance reached 78.6% by Day 5. Based on these results, the reference substance met the acceptability criteria defined in the protocol (>60% degradation within 10 days) and confirmed that the microbial inoculum was viable and active.

Any other information on results incl. tables

10-day window:

Assuming biodegradation is linear between Day 5 and 21, the graph indicates that biodegradation reached> 10% after Day 6 and would have been >60% within a ten day window when no nitrification was assumed. The same conclusion cannot be inferred if complete nitrification was assumed, however the graph does indicate biodegradation would have been > 60% within a fourteen day window in this scenario. The application of a fourteen day window is considered acceptable by the guideline for closed bottle testing.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Oxygen consumed by the control did not exceed 1.5 mg O2/L. The oxygen levels remained at a measurable level in all treatments for the entire testing period. The reference substance met acceptability criteria.

Interpretation of results:

readily biodegradable

Remarks:

The test item is readily biodegradable under both scenarios, i.e. no nitrification and complete nitrification. It passes the 13-day window which applies to closed bottle testing.

Executive summary:

The test substance DL-2-aminopropan-1-ol was readily biodegradable in OECD 301D protocol, based on 94.5% (assuming no nitrification) and 62.8% (assuming complete nitrification) degradation by Day 29.

The percent degradation for the reference substance reached 78.6% by Day 5, meeting the test acceptability criteria (>60% biodegradation within 10 days) and further supported the presence of a viable and active microbial population.