N-(1,3-dimethylbutylidene)-5-[(1,3-dimethylbutylidene)amino]-1,3,3-trimethylcyclohexanemethylamine

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:

27/01/2020-16/06/2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

liquid

Specific details on test material used for the study:

Information as provided by the Sponsor.
Identification:
CAS 71077-09-3
CAS Number:
71077-09-3
Batch:
12846
Purity:
97.32%
Physical State/Appearance:
Pale yellow viscous liquid
Expiry Date:
30 November 2020
Storage Conditions:
Room temperature in the dark, under nitrogen

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

A mixed population of activated sewage sludge micro-organisms was obtained on 02 March 2020 from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.
3.3.2 Preparation of Inoculum
The activated sewage sludge sample was washed twice by settlement and re-suspension in mineral medium to remove any excessive amounts of Dissolved Organic Carbon (DOC) that may have been present. The washed sample was then maintained on continuous aeration in the laboratory at a temperature of approximately 21 ºC and used on the day of collection. Determination of the suspended solids level of the activated sewage sludge was carried out by filtering a sample (100 mL) of the washed activated sewage sludge by suction through a pre-weighed Whatman GF/A filter paper* using a Buchner funnel. Filtration was then continued for a further 3 minutes after rinsing the filter three successive times with 10 mL of deionized reverse osmosis water. The filter paper was then dried in an oven at approximately 105 ºC for at least 1-Hour and allowed to cool before weighing. This process was repeated until a constant weight was attained. The suspended solids concentration was equal to 3.4 g/L prior to use.

Initial test substance concentration

Initial conc.:

12.7 mg/L

Based on:

IC (inorganic carbon)

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:

0

St. dev.:

0

Sampling time:

29 d

BOD5 / COD results

Results with reference substance:

Total organic carbon of the diluted sodium benzoate stock solution confirmed that it had been prepared correctly.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item attained 0% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Executive summary:

1 SUMMARY

1.1 Introduction

A study was performed to assess the ready biodegradability of the test item in an aerobic aqueous medium when exposed to sewage sludge micro-organisms under defined conditions. Carbon dioxide (CO2) evolution from the test item was followed by means of Inorganic Carbon (IC) analysis over a period of 28 days when exposed to sewage sludge micro-organisms under defined conditions. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No. 301B, "Ready Biodegradability; CO2 Evolution Test" referenced as Method C.4-C of Commission Regulation (EC) No. 440/2008 and US EPA Fate, Transport and Transformation Test Guidelines OCSPP 835.3110 (Paragraph (m)).

1.2 Methods

The test item, at a concentration of 10 mg carbon/L, was exposed to activated sewage sludge micro-organisms with mineral medium in sealed culture vessels in the dark at temperatures of between 22 °C and 24 °C for 28 days.

The biodegradation of the test item was assessed by the determination of carbon dioxide produced. Control solutions with inoculum and the reference item, sodium benzoate, together with a toxicity control were used for validation purposes.

1.3 Results

The test item attained 0% 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 82% biodegradation after 14 days with greater than 60% degradation being attained in a 10-day window. These results confirmed the suitability of the inoculum and test conditions and satisfied the validation criterion given in the OECD Test Guidelines.