Ethanol, 2-[(3-nitropyrazolo[1,5-a]pyridin-2-yl)oxy]-

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:

From November 19, 2014, to January 12, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well described study performed according to OECD guideline and GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes

Remarks:

Certificate available in the attached report.

Test material

Test material information

Constituent 1

Reference substance name:

2-({3-nitropyrazolo[1,5-a]pyridin-2-yl}oxy)ethan-1-ol

EC Number:

938-829-3

Cas Number:

936103-10-5

Molecular formula:

C9H9N3O4

IUPAC Name:

2-({3-nitropyrazolo[1,5-a]pyridin-2-yl}oxy)ethan-1-ol

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

Microorganisms from a domestic waste water treatment plant was supplied by the sewage plant Rossdorf, Germany.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial conc.:

ca. 102.9 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The test item was exposed to aerobic activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

Name: Sodium Benzoate Batch No.: 110M1219V Retest Date: November 2014 Purity: 100.4% Appearance : White solid Quality Release Date: December 09, 2010 Theoretical Oxygen Demand: ThODNH4: 1.666 mg oxygen per mg sodium benzoate (calculated)

Results and discussion

Test performance:

VALIDITY CRITERIA OF THE STUDY :

Inoculum Control: The oxygen demand of the inoculum control (medium and inoculum) was 30 mg O2/L and thus not greater than 60 mg O2/L within 28 days as required by the test guideline.

pH-Value: The pH-value of the test item flasks at the end of the test was 7.2 and therefore within the range of pH 6.0 to 8.5 as required by the test guideline.

Reference Item: The percentage degradation of the reference item should reach the level for ready biodegradability (>60%) within 14 days as required by the test guideline. The reference item sodium benzoate was degraded to more than 60% after 3 days of incubation.

Test Item: The difference of duplicate values for the degradation of the test item at the end of the test was above 20% due to the very low degradation values. The difference of duplicate values at day 28 differed by 47%. The validity criterion was not fulfilled. Both replicates differed by one digit, which resulted in degradation values of 5% and 10% causing the high variation due to mathematical calculations.

Toxicity Control: In the toxicity test, containing both the test substance and a reference compound more than 25% biodegradation (66% based on total ThOD) occurred within 14 days, therefore the test substance can be assumed to be not inhibitory.

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

ca. 1

Sampling time:

1 d

Remarks on result:

other: Average solution 1 and 2

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

ca. 10

Sampling time:

13 d

Remarks on result:

other: Average solution 1 and 2

% Degradation 3

Parameter:

% degradation (O2 consumption)

Value:

ca. 12

Sampling time:

23 d

Remarks on result:

other: Average solution 1 and 2

% Degradation 4

Parameter:

% degradation (O2 consumption)

Value:

ca. 8

Sampling time:

28 d

Remarks on result:

other: Average solution 1 and 2

Details on results:

Percentage Biodegradation: The test item contains nitrogen; therefore the evaluation of biodegradation has to be based ThODNH4 and ThONO3.The criterion for ready biodegradability under the conditions of a manometric respirometry test is the 10-day window, describing the period between reaching at least 10% degradation and 60% degradation. This period should not exceed 10 days.
The mean biodegradation of 10% of R0056895 was reached at day 13 (ThODNH4). At the end of the 10-day window at day 23, the degradation of R0056895A was 12% (ThODNH4) and therefore the 10 day window criterion was not passed. Based on ThODNO3, the biodegradation
did not reach 10% within the incubation time of 28 days. The mean biodegradation at test end after 28 days was 8% (ThODNH4) and 4% (ThODNO3).

Conclusion: The degradation rate of R0056895A did not reach 60% within the 10-day window or after 28 days.
Therefore, R0056895A is considered to be not readily biodegradable.

BOD5 / COD results

Results with reference substance:

Percentage Biodegradation: The reference item sodium benzoate was sufficiently degraded to 81% after 14 days and to 84% after 28 days of incubation.

Conclusion: The percentage biodegradation of the reference item confirms the suitability of the used aerobic activated sludge inoculum.

Applicant's summary and conclusion

Validity criteria fulfilled:

no

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance is considered to be not readily biodegradable.