N-octylpyridin-4-amine

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:

Experimental start date 13 March 2018, Experimental completion date 25 April 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

yes

Remarks:

On Day 14 of the study the flow rate for Inoculum Control Replicate 1 was measured to be 20 mL/minute.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N-octylpyridin-4-amine

EC Number:

265-019-0

EC Name:

N-octylpyridin-4-amine

Cas Number:

64690-19-3

Molecular formula:

C13H22N2

IUPAC Name:

N-octylpyridin-4-amine

Specific details on test material used for the study:

Test Item and Supporting Information
Information as provided by the Sponsor.
Identification: N-Octyl-4-pyridinamine
Batch: 80030735B
Purity: not supplied
Physical state/Appearance: white solid
Expiry Date: 28 November 2018
Storage Conditions: room temperature in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

A mixed population of activated sewage sludge micro organisms was obtained on 12 March 2018 from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.

Duration of test (contact time):

29 d

Initial test substance concentration

Initial conc.:

13.2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

13

Sampling time:

28 d

Any other information on results incl. tables

 Validation Criteriaand Biodegradation

The total CO₂evolution in the inoculum control vessels on Day 28 was 33.10 mg/L and therefore satisfied the validation criterion given in the OECD Test Guidelines. 

The IC content of the test item suspension in the mineral medium at the start of the test was below 5% of the TC content and hence satisfied the validation criterion given in the OECD Test Guidelines.

The difference between the values for CO₂production at the end of the test for the replicate vessels was <20% and hence satisfied the validation criterion given in the OECD Test Guidelines.

Acidification of the test vessels on Day 28 followed by the final analyses on Day 29 was conducted according to the methods specified in the Test Guidelines. This acidification effectively kills the micro‑organisms present and drives off any dissolved CO₂present in the test vessels. Therefore any additional CO₂detected in the Day 29 samples originated from dissolved CO₂that was present in the test vessels on Day 28 and hence the biodegradation value calculated from the Day 29 analyses is taken as being the final biodegradation value for the test item.

The results of the inorganic carbon analysis of samples from the first absorber vessels on Day 29 showed an increase in all replicate vessels with the exception of inoculum control Replicate 1 and procedure control Replicate 2. 

Inorganic carbon analysis of the samples from the second absorber vessels on Day 29 confirmed that no significant carry-over of CO₂into the second absorber vessels occurred.

The test item attained 13% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Sodium benzoate attained 64% biodegradation after 14 days with greater than 60% degradation being attained in a 10-Day window. After 28 days 84% biodegradation was attained. These results confirmed the suitability of the inoculum and test conditions and satisfied the validation criterion given in the OECD Test Guidelines.   

The toxicity control only attained 22% biodegradation after 14 days and 38% biodegradation after 28 days thereby confirming that the test item exhibited inhibitory effect on the sewage treatment micro‑organisms used in the test. 

Therefore, care should be taken in the interpretation of these results as the toxicity control vessel did not pass the validation criteria whereby it should attain equal to or greater than 25% biodegradation by Day 14 of the study for the test item to be considered non-inhibitory.

Day	Biodegradation (%)
	Procedure Control	Test Item	Toxicity Control
0	0	0	0
2	20	0	19
6	23	0	17
8	28	0	19
10	55	0	19
14	64	0	22
21	78	1	36
28	82	8	35
29*	84	13	38

*Day 29 values corrected to include any carry-over of CO₂detected in Absorber 2

Conclusion

The test item attained 13% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

The reference item, Sodium benzoate attained 64% biodegradation after 14 days with greater than 60% degradation being attained in a 10-Day window. After 28 days 84% biodegradation was attained. These results confirmed the suitability of the inoculum and test conditions and satisfied the validation criterion given in the OECD Test Guidelines.   

The toxicity control only attained 22% biodegradation after 14 days and 38% biodegradation after 28 days thereby confirming that the test item exhibited inhibitory effect on the sewage treatment micro‑organisms used in the test. 

Therefore, care should be taken in the interpretation of these results as the toxicity control vessel did not pass the validation criteria whereby it should attain equal to or greater than 25% biodegradation by Day 14 of the study for the test item to be considered non-inhibitory.

 

Applicant's summary and conclusion

Validity criteria fulfilled:

no

Interpretation of results:

not readily biodegradable

Conclusions:

The test item attained 13% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.
The reference item, Sodium benzoate attained 64% biodegradation after 14 days with greater than 60% degradation being attained in a 10-Day window. After 28 days 84% biodegradation was attained. These results confirmed the suitability of the inoculum and test conditions and satisfied the validation criterion given in the OECD Test Guidelines.   
The toxicity control only attained 22% biodegradation after 14 days and 38% biodegradation after 28 days thereby confirming that the test item exhibited inhibitory effect on the sewage treatment micro-organisms used in the test. 
Therefore, care should be taken in the interpretation of these results as the toxicity control vessel did not pass the validation criteria whereby it should attain equal to or greater than 25% biodegradation by Day 14 of the study for the test item to be considered non-inhibitory.