Reaction products of N,N'-ethane-1,2-diylbis(1,3-propanediamine), cyclohexane, peroxidized 4-butylamino-2,2,6,6-tetramethylpiperidine and 2,4,6-trichloro-1,3,5-triazine

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:

1997-05-30 - 1997-11-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study (OECD test guideline 301 B)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

Inoculum Source: Sewage treatment plant (Jupiter, Florida)
Approximately 2 liters of secondary effluent were collected and prepared for testing.

Duration of test (contact time):

28 d

Initial conc.:

20 other: mg carbon/L

Based on:

other: CO2 evolution

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST SUBSTANCE
- A stock solution of the test substance was not prepared due to the poor water solubility of the test substance.
- The test substance was initially dispersed in 300 mL test water with an ultrasonic bath and then added to the test container.
- A uniform suspension of the test substance was obtained after ultrasonic dispersion.

TEST CONDITIONS
- Composition of medium: Addition of 10 mL of a phosphate buffer solution and 1.0 mL each of ferric chloride, magnesium sulfate, and calcium chloride solutions to test water and bringing to a final volume of 1 L. All mineral salt solutions were prepared as described in OECD Guideline 301B
- Test temperature: 22 +/- 2 °C
- pH (mean values): 7.21 (day 0), 6.50 (day 28)

TEST SYSTEM
- Culturing apparatus:
- A total of seven 4 L test bottles were used. Two bottles were used for the blank control, two bottles were used for the test substance and one bottle served as the sterile control. The concentration of the test substance in these five bottles was 20 mg carbon/L.
- One bottle was used as a reference unit at a concentration of 19.9 mg carbon/L.
- The final bottle served as a toxicity control and contained 20 mg carbon/L (10 mg carbon/L test substance and 10 mg carbon/L as reference substance)
- To each bottle (except the sterile control bottle), 30 mL of inoculum, 550 mL of mineral salt, and 2000 mL of test water were added. The sterile control bottle received only the 550 mL of mineral salt solution.
- Air supply: purged with CO2-free air for 24 hours (~40 mL/minute)
- After purging the bottles with the CO2-free air for 24 hours, 420 mL of test water was added into each bottle in the blank unit. The reference bottle received 77.0 mL of reference substance stock solution and 343 mL of test water. The final concentration of reference substance in this solution was 19.9 mg carbon/L. Each bottle in the test unit received 87.8 mg of test substance and 420 mL of test water. The sterile control bottle received 87.8 mg of test substance, 350 mL test water and 2100 mL of isopropanol. The toxicity control bottle received 39 mL of reference stock solution, 43.9 mg of test substance and 381 mL of test water.
- Number of culture flasks/concentration: 2
- The content of each bottle was continuously stirred with a magnetic stirrer.

SAMPLING/MEASUREMENT
- The evolved CO2 from each bottle was trapped in a series of two gas-washing bottles containing 100 mL of 0.0125 M Ba(OH)2 on the days 1, 3, 5, 7, 10, 13, 17, 21, 22, 28.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Reference control: yes (aniline)

STATISTICAL METHODS / DATA:
The percent biodegradability at each time interval was calculated for the test and reference systems from the results of cumulative CO2 production using the following algorithm: Percent Biodegradability = (cumulative O2 produced (mg) x 100 / TOC added (mg) x 3.67)

Reference substance:

aniline

Remarks:

20 mg carbon/L

Parameter:

% degradation (CO2 evolution)

Value:

4.37

Sampling time:

28 d

Remarks on result:

other: 20 mg carbon test substance/L

Details on results:

The test item is not biodegradable when exposed to a 1% inoculum concentration of microorganisms maintained in an aerobic, aqueous
mineralized environment (<10% cumulative CO2 biodegradation rate within a 28-day test period).

Results with reference substance:

Cumulative biodegradation of the reference substance was 68.6 % by the end of the 10-day window meeting the test criteria for
acceptability.

Validity criteria fulfilled:

yes

Executive summary:

Ready biodegradability in water was studied according to OECD guideline 301B using activated sludge as inoculum. At a concentration of 20 mg carbon/L, cumulative biodegradation only reached 4.37% by day 28. The test item (as described in section 1.2) was dispersed in the test media without vehicle. No inhibitory effect on the bacteria was observed. The reference substance demonstrated the appropriate response. Based on the results the test item is not readily biodegradable.

Description of key information

The test substance is not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

Ready biodegradability in water was studied according to OECD guideline 301B using activated sludge as inoculum. At a concentration of 20 mg carbon/L, cumulative biodegradation only reached 4.37% by day 28. The test substance was dispersed in the test media without vehicle. No inhibitory effect on the bacteria was observed. The reference substance demonstrated the appropriate response. Based on the results the test substance is not readily biodegradable.