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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:
other: Guideline study and GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
TEST ITEM: Gro 266
Batch number: Gro-RN-9963-191
CAS-No.: 223398-24-1
Content: > 99 weight %
Chemical name: 4-Acetyl-1-methylpyridinium-p-toluolsulfonate
Appearance: White-beige powder
Sum formula: C8H10NO x C7H7SO3
Molecular weight: 307.37 g/mol
Water solubility: Approx. 500 g/L
pH value: Approx. 3.8 (200 g/L)

Expiry date: 2014-04-01
Recommended storage: Frigid, dark
Storage at test facility: 6 ± 2 °C, protected from moisture and light
Retention of test item: At least 1 g has been retained.
ldentification parameter at test facility: Name, batch number, state, consistency and colour

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
20 mg/L
Based on:
DOC

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
55
Sampling time:
28 d
Details on results:
The ready biodegradability of the test item Gro 266 (batch no.: Gro-RN-9963-191) was
determined with a non adapted activated sludge over a test period of 28 days in the Modified
Sturm Test. The study was conducted from 2009-08-20 to 2009-09-18 according to OECD 301 B
at Dr.U.Noack-Laboratorien. The test item was tested at a concentration of 20 mg/L in
duplicates, corresponding to a carbon content (TOC) of 11.6 mgC/L in the test vessels. The
biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2
produced by the respiration of bacteria. The degradation was stopped on day 28 by acidification
of the test solutions. The last titration was made on day 29, after residual CO2 had been purged
from the test solutions over a period of 24 h. The percentage CO2 production was calculated in
relation to the theoretical CO2 production (ThCO2) of the test item. The biodegradation rate was
calculated for each titration time.
To check the activity of the test system, sodium benzoate was used as functional control. The
percentage degradation of the functional control reached the pass level of 60 % after 7 days and
came to a maximum of 95 % after 28 days.
ln the toxicity control containing both test and reference item a biodegradation rate of 57 % was
determined within 14 days and it came to 66 % after 28 days. The biodegradation of the
reference item was not inhibited by the test item in the toxicity control.
The test item reached the 10 % level (beginning of biodegradation) after6 days. The 60 % pass level was not reached within the 10-d-window.
The 1st replicate reached a biodegradation rate of 45 % after 28 days, whereas the 2nd
replicate had reached the 60 % pass level after 26 days and came to a biodegradation rate of
65 % after 28 days. The mean biodegradation rate after 28 days was 55 %.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: moderately biodegradable
Conclusions:
The test item Gro 266 is considered as "moderately biodegradable". The mean biodegradation rate after 28 days was 55 %.