2,5-dimethyl-1H-pyrrole

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:

2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guideline Study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2,5-dimethyl-1H-pyrrole

EC Number:

210-913-8

EC Name:

2,5-dimethyl-1H-pyrrole

Cas Number:

625-84-3

Molecular formula:

C6H9N

IUPAC Name:

2,5-dimethyl-1H-pyrrole

Constituent 2

Reference substance name:

2,5-Dimethylpyrrole

IUPAC Name:

2,5-Dimethylpyrrole

Test material form:

other: yellowish liquid

Details on test material:

2,5-Dimethylpyrrole was a yellowish liquid with a purity of 99.7%.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

The source of test organisms was activated sludge
freshly obtained from a municipal sewage treatment
plant: 'Waterschap de Maaskant', 's-Hertogenbosch,
the Netherlands, receiving predominantly domestic
sewage.

Duration of test (contact time):

ca. 28 d

Details on study design:

28 days (last CO2-measurement on the 29th day).
During the test period the test media were aerated
and stirred continuously.

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

ca. 16 - ca. 17

Sampling time:

28 d

Details on results:

2,5-Dimethylpyrrole was found not to inhibit microbial activity.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

not readily biodegradable

Interpretation of results:

other:

Conclusions:

The relative degradation values calculated from the measurements performed during the test
period revealed 16 and 17% degradation of 2,5-Dimethylpyrrole, for the duplicate bottles tested.
Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 1a-day
window) was not met.
In conclusion, 2,5-Dimethylpyrrole was not readily biodegradable under the conditions of the
modified Sturm test presently performed.

Executive summary:

Determination of 'ready' biodegradability: carbon dioxide (C02) evolution test (modified Sturm

test) with 2,5-Dimethylpyrrole.

The study procedure was based on EEC directive 92/69, CA-C, December 1992, OECD

guideline No. 301 B July 17, 1992 and ISO Standard 9439 (1999).

2,5-Dimethylpyrrole was a yellowish liquid with a purity of 99.7%. 2,5-Dimethylpyrrole was

tested in duplicate at 32 mg per 2 litres, corresponding to 12 mg TOC/1. The organic carbon

content was based on the molecular formula. The Theoretical CO2 production (ThC02 ) of

2,5-Dimethylpyrrole was calculated to be 2.77 mg CO2/mg.

The study consisted of six bottles:

2 blank controls (no test material),

2 test bottles (2,5-Dimethylpyrrole, 16.1 mg/I),

1 positive control (sodium acetate, 40.0 mg/I) and

1 toxicity control (2,5-Dimethylpyrrole, 16.1 mg/I; plus sodium acetate, 40.0 mg/I).

Since 2,5-Dimethylpyrrole was easily soluble in water the test media were prepared using a

stock solution of 1 g/I in Milli-RO water. Preparation was as much as possible performed under

yellow light and/or dimmed light conditions. A weighed amount of 1007.5 mg of

2,5-Dimethylpyrrole was dissolved in Milli-RO water and made up tol 000 ml.17 Minutes of

magnetic stirring was used to accelerate dissolution and to ensure homogeneity. The resulting

stock was a clear and colourless solution. Aliquots of 32 ml of the stock solution were added to

the test medium, containing the microbial organisms, of test substance bottles A and B and the

toxicity control. The test solutions were continuously stirred during the test, to ensure optimal

contact between the test substance and the test organisms.

The relative degradation values calculated from the measurements performed during the test

period revealed 16 and 17% degradation of 2,5-Dimethylpyrrole, for the duplicate bottles tested.

Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day

window) was not met. In the toxicity control, 2,5-Dimethylpyrrole was found not to inhibit

microbial activity.

Since all criteria for acceptability of the test were met, this study was considered to be valid.

In conclusion, 2,5-Dimethylpyrrole was not readily biodegradable under the conditions of the

modified Sturm test presently performed.