Nonamethylenediamine

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:

1992-06-02 to 1992-07-20

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Study Methods for the Degradation of Chemical Substances by Microorganisms, Etc. described in the Study Methods for New Chemicals Substances (Kanpogyo Notification No. 5, Yakuhatsu Notification No. 615, 49 Kikyoko Notification 392 issued in 1974)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Standard activated sludge was obtained from Chemicals Evaluation and Research Institute, Japan, on April 23, 1992

-Culture: The standard activated sludge was exposed to air for 23.5 hrs in an automatic quantitative incubator for standard actvated sludge. About 1/3 of the entire volume of the supernatant was removed 30 min after stopping exposure, and exposure was started again after adding the same volume of 0.1% synthetic sewage (NB1 = 1g each of glucose, peptone, and monopotassium phosphate were dissolved in 1 L of water and pH was adjusted to 7.0±1.0 using sodium hydroxide). These procedure were repeated everyday at culture temperature of 25±2°C

Duration of test (contact time):

28 d

Initial conc.:

> 0 - < 0 other: not specified in study

Parameter followed for biodegradation estimation:

TOC removal

Parameter followed for biodegradation estimation:

other: GC direct assay test substance removal

Parameter followed for biodegradation estimation:

other: BOD

Details on study design:

TEST CONDITIONS
- Composition of medium: Water was added to 3 ml each of Fluids A, B, C and D described in JIS K0102 - 21 (Testing methods for industrial wastewater;japanese industrial standard) to make 1L
- Additional substrate:no
- Solubilising agent (type and concentration if used):no
- Test temperature:25±0.3°C
- pH: see table 1.
- pH adjusted: yes
- Suspended solids concentration: 3,994 ppm; after inoculation: 30 ppm.
- Other:

TEST SYSTEM
- Number of culture flasks/concentration:
No. 1 = containing the test substance in water at 100 ppm (w/v);
No. 2, 3 and 4 = containing the test substance in the basic culture medium at 100 ppm (w/v);
No. 5 = containing the control substance in the basic culture medium at 100 ppm (w/v);
No. 6 = containing only the basic culture medium at 100 ppm (w/v) (blank contol). Test containers No. 2,3,4,5 and 6 were inoculated with 2.3 ml each of activated sludge.

- Measuring equipment: closed oxygen consumption meter
- Test performed in open system: no
- Other: Culture was continued for 28 days at 25±1°C with through stirring using a closed oxygen consumption meter to monitor changes in oxygen consumption over time. After completing 28-day culture, residual test substance was subjected to analysis to determine its amount.


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (Flask no. 6)
- Abiotic sterile control: yes (Flask no. 1)
- Other: positive blank / reference substance (Flask no. 5)

Reference substance:

other: benzenamine

Parameter:

other: GC direct assay of test substance removal

Value:

100

St. dev.:

0

Sampling time:

28 d

Parameter:

% degradation (TOC removal)

Value:

93.7

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

31.7

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

57.6

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

67.1

Sampling time:

28 d

Remarks on result:

other: corrected value: including calculations for residual NH3-N.

Details on results:

Since a gap was found between the mean % degradation determined based on oxygen consumption and that determined by direct assay, the concentration of ammonia nitrogen (NH3-N) in the contents of culture bottles was determined using the indophenol method*1 taking advantage of nitrogen atoms contained in the test substance. The absolute amount of NH3-N in culture bottles Nos. 2, 3, 4 and 6 was found to be 4.73, 4.45, 4.77 and 1.10 mg, respectively. The mean amount of NH3-N in culture bottles Nos. 2, 3 and 4 was 3.55 mg when the amount of NH3-N deriving from the basic culture medium in No. 6 was deducted.
The total amount of nitrogen deriving from the test substance in culture bottles was 5.31 mg when calculated using the equation shown below.


(¿C9H22N2, MW: 158.29)

These findings suggest that 66.9% of nitrogen deriving from the test substance remained as NH3-N. TOD was found to be 85 mg when it was calculated based on an assumption that the remaining 33.1% of nitrogen was decomposed up to NO2 in the present study, and the % degradation of the test substance on Day 28 was calculated to be 67.1%.
In conclusion, the test substance was regarded as an easily degradable substance based on the assessment criteria which consider substances as easily degradable if the % degradation determined from oxygen consumption is not less than 60% and that determined by direct assay is not less than 70%.

Results with reference substance:

The degradation of the control substance, calculated via BOD analysis, was 55.9% after 7 days and 68.9% after 14 days. Therefore validity criteria are met.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance was regarded as an easily degradable substance based on the assessment criteria which consider substances as easily degradable if the % degradation determined from oxygen consumption is not less than 60% and that determined by direct assay is not less than 70%.
The 10-day window was not taken into consideration.

Executive summary:

Biodegradability of NMDA was tested via screening of chemicals for ready biodegradability in an aerobic aqueous medium. NMDA was suspended in water and inoculated activated sluge and a basic culture medium were added. Culture was performed for 28 days. Afterwards, degradation of NMDA was determined via BOD determination and direct assay (TOC and GC analysis). Abiotic and sludge blanks were taken to verify the method. NMDA was observed to be readily biodegradable.

Description of key information

NMDA is readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

One study was conducted in GLP compliance and in accordance with the Study Methods for New Chemicals Substances (Kanpogyo Notification No. 5, Yakuhatsu Notification No. 615, 49 Kikyoko Notification 392 issued in 1974) to determine the biodegradation of the substance. In this test NMDA was determined to be readily biodegradable.