N,N-dimethylhydrazine

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:

05 August 2010 - 08 October 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Compliant to GLP and testing guideline; adequate coherence between data, comments and conclusions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N,N-dimethylhydrazine

EC Number:

200-316-0

EC Name:

N,N-dimethylhydrazine

Cas Number:

57-14-7

Molecular formula:

C2H8N2

IUPAC Name:

1,1-dimethylhydrazine

Details on test material:

- Name of test material (as cited in study report): UDMH (Unsymetrical Dimethyl Hydrazine)
- Physical state: liquid
- Analytical purity: 99.4%
- Impurities (identity and concentrations): water 0.2%, amines 0.4%, methanol <0.01%, chlorides 0.0022%, iron < 0.00006%, mechanical impurities < 0.0001%
- Purity test date: 10 september 2008
- Lot/batch No.: 1
- Expiration date of the lot/batch: 23 january 2012 (supplier's indication by e-mail)
- Storage conditions of test material: at room temperature

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

other: commercial preparation: BOD Seed Inoculum (Polyseed; InterLab)

Details on inoculum:

Expiration date : march 2011
Batch : 260903-1-0610-13
Supplier HACH
Product No. PK/50

Preparation: dispersed in 150 mL buffer solution, stirred 4 hours, filtered on folder filter.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

5.29 g/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation 1

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation 2

Parameter followed for biodegradation estimation:

other: NO2 and NO3 (to check if O2 consumption not due to nitrification)

Details on study design:

TEST CONDITIONS
- Test temperature: 21°C
- Continuous darkness: yes

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

24.5

Sampling time:

14 d

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

31.2

Sampling time:

28 d

Details on results:

No detectable nitrate or nitrite were produced.

BOD5 / COD results

BOD5 / COD

Parameter:

BOD5

Value:

0.41 g O2/g test mat.

Results with reference substance:

68 and 78% degraded at 14 and 28 days, resp.
BOD5 = 1.31 g O2/g test mat.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable, but biodegradable to some extent

Conclusions:

UDMH is not readily biodegradable. However some biodegradation occurred (31% within 4 weeks).

Executive summary:

The aim of this study was to determine aerobic ready biodegradability of test item by measurement of dissolved oxygen consumption for 28-day period. A suspension of the test item in a mineral medium was inoculated and incubated under aerobic conditions in the dark for 28 days. Biodegradation was followed by determination of oxygen uptake in closed bottle. For the test item Unsymetrical dimethyl hydrazine Batch n°1:

Percentage of biodegradation at 28 days	31 %
Conclusion	Not Readily Biodegradable

The test item contains N atoms. As there was no production of detectable nitrate and nitrite, the oxygen consumption was due to biodegradation and not denitrification.