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Biodegradation in water: screening tests

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biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
07 Jul - 04 Aug, 1994
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: done under OECD method and GLP

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guidelineopen allclose all
according to guideline
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
according to guideline
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
GLP compliance:

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
4-nitrophenyl (1,3-thiazol-5-yl)methyl carbonate hydrochloride

Study design

Oxygen conditions:
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
The test and std substances were dispersed directly in nutrient medium to give the foloowing series:
a) Inoculated nutrient medium
b) 5mg/l test solution
c) 3mg/l sodium benzoate
d) 5mg/l test solution + 3mg/l sodium benzoate.
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
280ml BOD bottles were incubated in a water bath at 21±1°C and oxygen detrmination performed at 0, 4, 7, 11, 14, 18, 21, 25 and 28 days.
Reference substance
Reference substance:
other: Sodium benzoate

Results and discussion

Preliminary study:
A-87439.1 attained 27% degredation after 28 days
Test performance:
Sodium benzoate attained 72% biodegredation within 28 days.
% Degradation
% degradation (O2 consumption)
Details on results:
Nitrate and nitrite analyses were conducted on day 0 and day 28.

Points of degradation plot (test substance):
8 % degradation after 4 d
13 % degradation after 7 d
11 % degradation after 11 d
9 % degradation after 14 d
20 % degradation after 18 d
35 % degradation after 21 d
29 % degradation after 25 d
27 % degradation after 28 d

BOD5 / COD results

Results with reference substance:
Points of degradation plot (reference substance):
70 % degradation after 4 d
70 % degradation after 7 d
72 % degradation after 11 d
65 % degradation after 14 d
67 % degradation after 18 d
71 % degradation after 21 d
64 % degradation after 25 d
72 % degradation after 28 d

Any other information on results incl. tables

Oxygen depletion levels in the inoculated control series were within the prescribed limits of ≤1.5mg O2/l after 28 days.

Cultures containing both test and standard substances combined showed an oxygen depletion value 4% lower than that anticipated on the basis of results from separate cultures at day 14. Consequently, A-87439.1 is not considered to have had an inhibitory effect on sewage bacteria under the conditions of the test.

Applicant's summary and conclusion

Validity criteria fulfilled:
Interpretation of results:
other: not readily biodegradble
The test material attained 27% degradation after 28 days and therefore cannot be considered to be readily biodegradable.
Executive summary:

After correcting the total oxygen consumption (1.355 mgO2/l) for that attributable to nitrification (1.37mg O2/l) the true oxygen consumption value for carbonaceous biodegredation after 28 days is obtained, i.e. 0%.