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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Reference substance name:
Reaction products of fatty acids, C12 alkyl and triglycerides, C18 (unsaturated) alkyl with 2-(2-aminoethylamino)ethanol and sodium chloroacetate
EC Number:
944-415-3
Molecular formula:
not applicable being an UVCB
IUPAC Name:
Reaction products of fatty acids, C12 alkyl and triglycerides, C18 (unsaturated) alkyl with 2-(2-aminoethylamino)ethanol and sodium chloroacetate
Test material form:
other: viscous solid
Details on test material:
Substance obtained by dehydration of an aqueous solution

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
Non-adapted activated sludge from the aeration tank of the ARA Werdhölzli (CH-8048 Zürich), a municipal biological waste water treatment plant. 30 mg/l dry matter in the final mixture
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimationopen allclose all
Parameter followed for biodegradation estimation:
O2 consumption
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
Sampling1 September 2016; 9:00 a.m.Test units510 ml glass bottles (tightly closed with manometric BOD measuring devices) containing a total volume of test solution of 200 ml. The bottles are equipped with stirring rods and butyl rubber quivers which contain 2 pellets of sodium hydroxide each to absorb the produced CO2 from the head space.Temperature22 ± 2°C, controlled at ± 1°C, in a thermostat cabinetTest mediumAerobic mineral salts medium (Table 1) prepared with ultrapure water (conductivity: <1.5 µS/cm; DOC: <0.5 mg/l)FeedNone, test item and/or reference item as sole organic carbon sourcesTest duration 28 days
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (DOC removal)
Value:
ca. 72
Sampling time:
28 d
Parameter:
% degradation (O2 consumption)
Value:
ca. 50
Sampling time:
28 d
Details on results:
Toxicity control: At the applied initial test concentration of 154 mg/l the test item was not judged to have any inhibitory effect on the microbial population, since the biodegradation of the mixture (test item + reference item sodium benzoate) exceeded 25% within 14 days Abiotic sterile control: test item was not abiotically degraded (by processes using O2) during the whole test period of 28 days in the absence of microorganisms as confirmed by the lack of oxygen consumption

BOD5 / COD results

Results with reference substance:
The procedure control sodium benzoate reached 92% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: see considerations in the attached document
Conclusions:
The substance was tested for ready biodegradation following OECD 301F. Under the experimental conditions the O2 consumption is equal to 50% and DOC removal 72%
Executive summary:

The biodegradability of the substance exposed to microorganisms derived from activated sludge of a municipal sewage treatment plant was investigated under aerobic static exposure conditions, following the test guideline OECD 301 F.

The biodegradability of the substance based on O2consumption was calculated to be 50% after 28 days as compared to the chemical oxygen demand (COD).

Biodegradation of the test item was observed without any lag-phase.

The procedure control sodium benzoate reached 92% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.

The total elimination calculated based on dissolved organic carbon (DOC) measurements reached 72% for the substance and 98% for sodium benzoate, respectively. This data confirms the limited biodegradabilityof the test item.