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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:
2012-08-23 to 2012-09-20
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well-documented GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Ministerium für Arbeit, Intergration und Soziales des Landes Nordrhein-Westfalen

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous
Details on test material:
Name as cited in the study report: Additin E 459
Other name: Triethylene glycol dimaleate
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
At the time of the testing the CAS Number that was used for Triethylene glycol dimaleate was 66790-57-6
In the course of the project the CAS Number 109828-01-5 was assigned, as this number describes better the structure of the main compound

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
Type: mixed population of aquatic microorganisms
Origin: aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal)
Preparation: The sludge was washed twice by adding mineral medium and centrifuging for 10 min at 2000 rpm and 20 °C and decanting off the supernatant
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Remarks:
(Blank-corrected BOD)
Details on study design:
The endogenous activity of the inoculum was checked running parallel blanks with inoculum but without test item. A reference compound (sodium benzoate) was run in parallel to check the operation of the procedures.
A toxicity control (test item and reference compound mixed) was run in parallel, to ensure that the chosen concentration of the test item was not inhibitory to microorganisms.
Degradation was followed by the determination of oxygen uptake and measurements were taken at frequent intervals to allow the identification of the beginning and end of biodegradation and the slope of the biodegradation curve.
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
other: blank-corrected BOD
Value:
83
Sampling time:
28 d
Details on results:
Degradation of test material:
24% after 7 days
65% after 14 days
81% after 21 days
83% after 28 days

BOD5 / COD results

Results with reference substance:
The reference compound sodium benzoate showed 88 % degradation after 14 days.

Any other information on results incl. tables

All validity criteria of the test method were met:

The reference compound reached the level of = 60 percent for ready biodegradability within 14 days (table 4).

The toxicity control exhibited degradation rates > 25 % within 14 days (table 5).

At the end of the test, at the plateau, or the end of the 10-d window, biodegradation in parallels with test item did not differ by more than 20 percentage points (table 3).

The oxygen uptake of the inoculum blank was = 60 mg/L (table 1).

In cases where the degradation was = 60 %, the pH values (table 2) were in between 6.0 and 8.5 at the end of the test.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Validity criteria of the OECD test guideline are fulfilled.
Interpretation of results:
readily biodegradable
Conclusions:
Within 28 days, a degradation rate of 83 % was determined for Additin E 459.
Additin E 459 is considered to be "Readily Biodegradable".
Executive summary:

A study was performed to assess the ready biodegradability of Additin E 459.

The study was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.4-D “Manometric Respirometry Test“(2008). This test method is in all essential parts identical with OECD Guideline 301 F (adopted July 1992).

A solution of Additin E 459 in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by continuous automated BOD determinations.

Additin E 459 showed:

24 % degradation after 7 days

65 % degradation after 14 days

81 % degradation after 21 days

83 % degradation after 28 days

Therefore, Additin E 459 is considered to be “Readily Biodegradable“.

The reference compound sodium benzoate showed 88 % degradation after 14 days.