Registration Dossier

Environmental fate & pathways

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:
1988-12-01 - 1988-12-29 (experimental phase)
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
no GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
Deviations:
no
GLP compliance:
no
Remarks:
study conducted before 2008

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
sewage, predominantly domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): secondary effluent of a domestic sewage treatment plant (Wupper area water authority, STP Odenthal)
- Pretreatment: separation of coarse particles by filtration; aeration of filtrate
- Concentration of sludge: 5 ml/L (effluent concentration in reaction mixture)
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
51.2 mg/L
Based on:
test mat.
Initial conc.:
1.56 other: mg O2/mg
Based on:
COD
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: mineral medium
- Test temperature: 20 ± 1 °C
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
1
Sampling time:
28 d

BOD5 / COD results

BOD5 / COD
Parameter:
COD
Value:
1.56 other: mg O2/mg
Results with reference substance:
88% degradation after 28 days has been determined with the reference substance aniline.
Theoretical Oxygen Demand (ThOD): 2409 mg/g

Any other information on results incl. tables

Degradation of test item

   5d  15d  28d
 BOD (mg/L)  0.50  0.45  0.50
 % degradation  1  1  1

Degradation of reference substance

Test concentration: 1.2 mg/L

   5d  15d  28d
 BOD (mg/L)  1.95  2.35  2.55
 %degradation  67  81  88

Oxygen measurement

Dissolved oxygen of mineral medium:

(mg O2/L after x days)

bottle-no.   0 days
 1  9.3
 2  9.3
 mean 9.3 

Dissolved oxygen of blank inoculum:

(mg O2/L after x days)

bottle-no.   0 days  bottle-no.  5 days  bottle-no.  15 days  bottle-no.  28 days
 3  8.80  5  8.80  7  8.70  9  8.70
 4  8.80  6  8.80  8  8.70  10  8.70
 mean  8.80    8.80    8.70    8.70

Dissolved oxygen of test item:

(mg O2/L after x days)

bottle-no.   0 days  bottle-no.  5 days  bottle-no.  15 days  bottle-no.  28 days
 11  8.90  13  8.80  15  8.70  17  8.70
 12  8.80  14  8.80  16  8.80  18  8.70
 mean  8.85    8.80    8.75    8.70

Dissolved oxygen of reference substance:

(mg O2/L after x days)

bottle-no.   0 days  bottle-no.  5 days  bottle-no.  15 days  bottle-no.  28 days
 19  8.80  21  7.40  23  6.80  25  6.70
 20  8.80  22  7.30  24  6.90  26  6.60
 mean  8.80    7.35    6.85    6.65

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Interpretation of results:
not readily biodegradable
Conclusions:
The study was conducted according to OECD 301 F on the registered substance itself. The method is to be considered scientifically reasonable and suitable for the test item with some deficiencies in documentation, but the available information allows the conclusion that the test was properly conducted. Hence, the results can be considered as reliable to assess ready biodegradability of the test item. A degradation of 1 % was determined, hence, the test item needs to be classified as not readily biodegradable.
Executive summary:

This report is based on a study report “Biodegradability of Pyridon, rein, trocken" (1988), the corresponding raw data and additional information from the executing laboratory “Institut für Umweltanalyse”, Dr. Kanne (Bayer AG Leverkusen – Germany). Recent regulatory requirements necessitate this re-evaluation.

The study was conducted in accordance EU method C.4-E. This test method is in all essential parts identical with OECD 301D.

A solution of the test item in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by BOD determinations. The reference compound aniline showed 81 % degradation after 15 days.

Result:

1 % degradation after 5 days

1 % degradation after 15 days

1 % degradation after 28 days

Therefore the test item is considered to be “not readily biodegradable“.