2-tert-butylaminoethyl methacrylate

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:

start 12-06-1996 till 06-08-1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, GLP, All validity criteria fulfilled, limited identification of test substance

Qualifier:

according to guideline

Guideline:

EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (old version) (Ready Biodegradability: Modified AFNOR Test)

Version / remarks:

from 17/07/1992

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

The inoculum is from the secondary effluent of the urban biological sewage treatment station Versailles. The effluent, taken on the day of inoculation of the flasks. As pretreatment the inoculumwas centrifuged at about 20 ° C for 20 minutes at 4000 g.
After centrifugation the pellet is taken up in a volume of the test medium such that there is a concentration factor of about 150 compared it the effluent sample. Total Bacteria Count for Millipore shows that the inoculum concentrate had a concentration of 1.18 x 10^6 bact/mL, which results in
1.18 · 10^4 bacteria/mL in the final test (1% inoculum in the final test).

Duration of test (contact time):

28 d

Initial conc.:

15 mg/L

Based on:

COD

Initial conc.:

23.1 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

other: COD

Details on study design:

A known volume of inoculated mineral medium containing a known concentration of the substance to be studied (between 10 and 40 mg/L COD) as the sole source of organic carbon rated. The solution is aerated at 22 ± 2 ° C in the dark. Organic substances dissolved in water are biodegraded by chemotherapy organotrophic microorganisms that use the substance as soule source of carbon and energy. Organic carbon remaining in solution is measured at the beginning and end of the test (usually 28 days) and intermediate time intervals short enough to determine the 10day window interval at the beginning and end of biodegradation.

Reference substance:

benzoic acid, sodium salt

Test performance:

The test vessels were accurately weighed to ±0.1 g and incubated in a thermostated room at 22 ± 2 ° C. COD analysis was performed at time 0 (the beginning of the trial, after homogenization), 3,6,9. 14, 17, 20, 24, and 28 days (end of test).

Parameter:

other: COD

Value:

37

Sampling time:

28 d

Parameter:

other: COD

Value:

48

Sampling time:

24 d

Details on results:

The maximum level of degradation of test substance is: 48% in 24 days.
The lag period for the degradation of the substance (time elapsed between the beginning of the test and 10% degradation) is about 1 day and the percent of degradation at the end of the time interval of 10 days after lag phase is 37%. No degradation was observed in the sterile control (vial Fs).

According to test criteria, the test substance is not considered to be readily biodegradable. Due to the rigorous nature of this method however, a low value of degradation does not necessarily mean that the test substance it is not biodegradable under environmental conditions. But it indicates that additional studies are needed to evaluate its biodegradability.

Results with reference substance:

The percentage degradation of the reference substance (Fc) are above 70% in 14 days. The degradation of the reference substance has not been inhibited by the presence of the test substance in relation to the result of the reference substance without the presence of test substance.

No disappearance of substance due to physico chemical degradation or adsorption to the microorganisms has been observed.

Validity criteria fulfilled:

yes

Interpretation of results:

other: Parent degrades quickly to form a metabolite

Conclusions:

The test result is considered valid because the following validity criteria were fulfilled: The difference between the replicates with test substance (Ftl and Ft2) is less than 20%. The percentage degradation of the reference substance (Fc) are above 70% in 14 days. The degradation of the reference substance has not been inhibited by the presence of the test substance in relation to the result of the reference substance without the presence of test substance.

Executive summary:

The ready biodegradability of 2 -tert-butylaminoethylmethacrylate was determined in a DOC die-Away test performed according to OECD and EU Test Guidelines and in compliance with the OECD principles of Good Laboratory Practice.

2 -tert-butylaminoethylmethacrylate was biodegraded 48% after 24 days indicating that the substance should not be considered to be readily biodegradable. 2 -tert-butylaminoethylmethacrylate did not cause a reduction of the endogenous respiration.

The test substance is therefore considered to be non-inhibitory to the inoculum.

Description of key information

Ready biodegradability of 2-tert-butylaminoethyl methacrylate has been assessed in an OECD 301A and OECD 301D test. In both tests only partial degradation was observed.  The partial degradation observed is most likely due to the accumulation of an intermediate substance. 2-tert-butylaminoethyl methacrylate is susceptible to hydrolysis. From the two hydrolysis products metacrylic acid is most likely biodegraded and N-tert butyl, N-hydroxyethylamine (CAS no 4620-70-6) is most likely not degraded.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater

Additional information

The OECD 301A test is selected as the key study as this is a Kl. 1 study. In this study 37 % biodegradation was observed after 28 days. Already 39 % degradation was observed after 7 days, indicating that the parent is quickly and completely hydrolysed into two products from which one is degraded. The hydrolysis product remaining is most likely N-tert butyl, N-hydroxyethylamine (CAS no 4620-70-6).