Benzyldimethylamine

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial, non-adapted

Details on inoculum:

- Initial cell/biomass concentration: 1 g/l

Initial conc.:

400 mg/L

Based on:

other: DOC (calculated)

Initial conc.:

425 mg/L

Based on:

other: DOC (measured)

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- pH: 6.7 - 7.4
- pH adjusted: yes

Parameter:

% degradation (DOC removal)

Value:

90 - 100

Sampling time:

13 d

Results:

Time [d]	Blank value [mg/L]*	Test item DOC [mg/L]	DOC elimination	pH
0	17	425	-6	7.0
3 hours	17	409	2	7.0
1	17	418	0	7.0
4	17	223	48	6.7
7	17	23	98	7.0
13	17	21	99	7.8

* = Blank value was statistically determined (from blank controls with the same inoculum)

Interpretation of results:

inherently biodegradable

Conclusions:

Benzyldimethylamine was shown to be 100% inherently biodegradable after 13 days.

Executive summary:

The inherent biodegradability of benzyldimethylamine was tested in a study equivalent or similar to a 13-d- Zahn-Wellens test (OECD Guideline 302B). With an initial test substance concentration of 425 mg/L and an activated sludge (industrial, non-adadapted) with an initial cell/biomass concentration of 1 g/L 100% degradability of benzyldimethylamine was determined by DOC-removal.

Benzyldimethylamine was shown to be 100% inherently biodegradable after 13 days and fulfilled the criterion for inherent, ultimative biodegradability (70% degradability within 7 days).

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Qualifier:

according to guideline

Guideline:

other: "Biodegradation test of chemical substance by mircoorganisms etc." stipulated in the order Prescribing the Items of the test relating to the new chemical substance (1974)

Principles of method if other than guideline:

This guideline corresponds to 301C, ready biodegradability: modified MITI Test (I) or 302C, inherent biodegradability: modified MITI Test (II) stipulated in the OECD Guidelines for testing of chemicals (May 12, 1981)

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

Sludge concentration: 30 mg/L related to BOD

Preparation of acitvated sludge:

Sludge sampling sites and time
Sampling were made four times in every year at ten places in Japan. Details are reread in bibliographic source mentioned above

Mixing of fresh and old activated sludge
5L of the filtrate of the supernatant of an activated sludge in the present use was mixed with 500 mL of the filtrate of the supernatant of a newly collected sludge respectively and the mixture was cultured at 7.0 +- 1.0 under the sufficient aeration (prefiltered open air was used for aeration)

Culture
About 30 minutes after ceasing the aeration to the sludge mixture, supernatant corresponding to about 1/3 of the whole volume was removed. Then the equal volume of dechlorination water was added to the remaining portion and aerated again, followed by addition of synthetic sewage*, concentration of that portion was to be 0.1 (W/V)%. This procedure was repeated once every day. The culturing was carried out at 25+-2°C.
*synthetic sewage: glucose, peptone and monopotassium phosphate were dissolved in dechlorination water respectively. Each concentration of them was to be 5(W/V)% and the solution was adjusted to pH 7.0 +- 1.0 with sodium hydroxide.

Control
During the cultivation, appearance of the supernatant, precipitabiltiy, formation of flock, pH, dissolved oxygen concentration in the solution and temperature were checked and necessary adjustments were made. microflora in the activated sludge was microscopically observed and sludge with no abnormal symptom was used for the test.

Inspection of activity
Activity of the sludge was inspected to use reference substance. And the relation between new and old activated sludge was taken account.

Duration of test (contact time):

4 wk

Initial conc.:

100 mg/L

Based on:

test mat.

Reference substance:

aniline

Remarks:

guaranteed reagent, Showa Chemicals Inc.

Parameter:

% degradation (O2 consumption)

Value:

0 - 2

Sampling time:

4 wk

Interpretation of results:

not readily biodegradable

Executive summary:

The ready biodegradability of benzyldimethylamine was tested according to "Biodegradation test of chemical substance by mircoorganisms etc." stipulated in the order Prescribing the Items of the test relating to the new chemical substance (1974). (This guideline corresponds to 301C, ready biodegradability: modified MITI Test (I) or 302C, inherent biodegradability: modified MITI Test (II) stipulated in the OECD Guidelines for testing of chemicals (May 12, 1981)).

The biodegradation rate is 0 to 2 % after 4 weeks.

(MITI, 1992)

Description of key information

Benzyldimethylamine was shown to be not ready biodegradable in different ready biodegradability tests using non-adapted sludge (MITI, 1992). In addition, Benzyldimethylamine was shown to be 100% inherently biodegradable after 13 days and fulfilled the criterion for inherent, ultimative biodegradability (BASF, 1987).

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

READY BIODEGRADABILITY

 

Key study:

The ready biodegradability of benzyldimethylamine was tested according to "Biodegradation test of chemical substance by mircoorganisms etc." stipulated in the order prescribing the items of the test relating to the new chemical substance (1974). This guideline corresponds to 301C, ready biodegradability: modified MITI Test (I) or 302C, inherent biodegradability: modified MITI Test (II) stipulated in the OECD Guidelines for testing of chemicals (May 12, 1981). The biodegradation rate (measured as O2 consumption) is 0 to 2 % after 4 weeks. The substance is thus, not regarded ready biodegradable (MITI, 1992).

 

Supporting studies:

- A 4-wk Modified MITI Test (I) was performed on the basis of the OECD guideline 301C with activated sludge. 1% degradation was observed within 4 weeks on the basis of O2 consumption. Benzyldimethylamine is not readily biodegradable (MITI-Online, 2002)

- A 20-d ready biodegradability test was performed on the basis of the OECD guideline 301D with activated, non-adapted sludge under aerobic conditions. 0% degradation was observed within 20 days on the basis of O2 consumption. Benzyldimethylamine is not readily biodegradable (Bayer AG, 1979).

- A 20-d ready biodegradability test was performed on the basis of the OECD guideline 301D with activated, adapted sludge under aerobic conditions. 100% degradation was observed within 20 days on the basis of O2 consumption. Benzyldimethylamine is readily biodegradable with adapted sludge (Bayer AG, 1979).

 

INHERENT BIODEGRADABILITY

 

Key study:

The inherent biodegradability of benzyldimethylamine was tested in a study equivalent or similar to a 13-d- Zahn-Wellens test (OECD Guideline 302B). With an initial test substance concentration of 425 mg/L and an activated sludge (industrial, non-adadapted) with an initial cell/biomass concentration of 1 g/L 100% degradability of benzyldimethylamine was determined by DOC-removal.

Benzyldimethylamine was shown to be 100% inherently biodegradable after 13 days and fulfilled the criterion for inherent, ultimative biodegradability (70% degradability within 7 days).

A new inherent biodegradation test is currently on-going (2023), the dossier will be updated as soon as study report has been reviewed and agreed (Q4, 2023).