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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:
1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted in GLP compliance and in accordance with several internationally acknowledged guidelines for the testing of chemicals.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Qualifier:
according to
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid
Details on test material:
- Name of test material (as cited in study report): 2,6-DMPA
- Physical state: liquid
- Analytical purity: 98.8 %
- Purity test date: May 20, 1999
- Lot/batch No.: 34

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge : domestic waste water treatment plant
- Preparation of inoculum for exposure: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspened in tap water and again centrifuged. This procedure was
repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of the wet sludge
to its dry weight to determined. Based on this ratio, calculated aliquots of washed slidge suspension ,
corresponding to 1.5 g dry material per litre were mixed with test water and then aerated until use.
- Water filtered: no
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
ca. 25 other: mg
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Solubilising agent (type and concentration if used): no
- Test temperature: 22 °C
- pH: 7.6 at test start
- Light Conditions: darkness
- Suspended solids concentration: 30 mg/L

TEST SYSTEM
- Culturing apparatus: Manometric Test System with test flakes of a volume of 500 mL
- Number of culture flasks/concentration: 2
- Details of trap for CO2 and volatile organics if used: aqueous solution ( 45 % ) of potassium hydroxide

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes


Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Parameter:
% degradation (O2 consumption)
Value:
49 - 55
Sampling time:
28 d
Details on results:
The percentage biodegradation did not exceed 60 % within the 10-day window. The test substance can therefore not considered to be ready biodegradable.

BOD5 / COD results

Results with reference substance:
The reference compound Aniline was sufficiently degraded to 85 % after 14 days, and to 110% after 28 days of incubation. The percentage biodegradation of the reference compound confirms the suitability of the used activated sludge inoculum.

Any other information on results incl. tables

Biodegradation in the Toxicity Control:

In the toxicity control containing both, the test substance and the reference compound Aniline, 42 % biodegradation was noted within 14 days and 49 % biodegradation was determined after 28 days of incubation.

According to the test guidelines the test substance can be assumed to be not inhibitory on the activated sludge micro organisms because degradation was > 25 % within 14 days.

Abiotic Control:

The oxygen demand in the abiotic control was nearly the same as in the two control flasks

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: The test substance can therefore not considered to be ready biodegradable.
Conclusions:
The percentage biodegradation did not exceed 60 % within the 10-days window. The test substance can therefore not considered to be ready
biodegradable.