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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)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Directive 92/69/EC, C.4-A 28-day DOC die-away test
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Inoculum or test system:
other: aerobic activated sludge from a wastewater treatment plant treating predominantly domestic wastewater
Reference substance
Reference substance:
other: Sodium benzoate

Results and discussion

% Degradation
Parameter:
other: See report
Value:
ca. 2.5
St. dev.:
0
Sampling time:
28 d
Remarks on result:
other: see report
Details on results:
Points of degradation plot (test substance):
0 % degradation after 7 d
0 % degradation after 14 d
1 % degradation after 21 d
2.5 % degradation after 28 d

BOD5 / COD results

BOD5 / COD
Parameter:
COD
Value:
ca. 34 mg O2/g test mat.
Results with reference substance:
Points of degradation plot (reference substance):
98.5 % degradation after 7 d
99.5 % degradation after 14 d
99.5 % degradation after 21 d
99 % degradation after 28 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: not readily biodegradable
Conclusions:
3.1 DEGRADATION OF THE TEST ITEM
The results are presented in Tables 1 and 2, and in Figures 1 and 2.
In the test flasks containing the test item and activated sludge (inoculum] the DOC
concentrations (dissolved organic carbon corrected for the DOC of the inoculum controls)
varied between 33.1 and 34.6 mg/L over the exposure period of 28 days and were not
significantly different from the initial DOC concentrations of 34.0 and 34.1 mg/L measured on
Day 0. Expressed as percentage DOC removal, values in the range from -2 to 3% were
noted. Therefore, ucb 22060 was found to be not biodegradable under the conditions of the
test.
Abiotic control:
The results are presented in Table 1 and in Figure 1.
In the abiotic control, containing the test item and poisoned medium, the DOC
concentrations varied from 35.8 to 36.4 mg/L over the exposure period of 28 days and were
not significantly different from the initial DOC concentration of 34.9 mg/L measured at Day O.
Thus, no abiotic degradation occurred under the conditions of the test.
3.2 DEGRADATION OF THE REFERENCE ITEM
The results are presented in Tables 1 and 2, and in Figures 1 and 2,
In the procedure controls containing the reference item sodium benzoate and activated
sludge (inoculum), sodium benzoate was completely biodegraded within 7 days of exposure,
confirming suitability of the activated sludge.
3.3 DEGRADATION IN THE TOXICITY CONTROL
The results are presented in Tables 1 and 2, and in Figures 1 and 2.
In the toxicity control, containing the test item (corresponding to 57% of total DOC), the
reference item (corresponding to 43% of total DOC) and activated sludge (inoculum), the
initial DOC concentration (corrected for the DOC of the inoculum control) of 67.6 mg/L
measured on Day O decreased to 36.0 mg/L on Day 14. Biodegradation amounted to 47°4
within 14 days of exposure. Thus, according to the test guidelines the test item can be
assumed to not be inhibitory to activated sludge because degradation was >35Y0 within
14 days.
Executive summary:

The test item ucb 22060 was investigated for its ready biodegradability in a “28-Day DOC

Die-Away Test” according to EU Commission Directive 92/69 EEC, C.4-A (1992) and OECD

Guideline for Testing of Chemicals, No. 301 A (1992).

In the test flasks containing the test item ucb 22060 and activated sludge (inoculum) the

concentrations of dissolved organic carbon (DOC) were not significantly different from the

initial DOC concentrations measured on Day O. Therefore, ucb 22060 was found to be not

biodegradable under the conditions of the test.

In the abiotic control, containing the test item and poisoned mineral medium, no degradation

was noted after 28 days of exposure (based on DOC measurements).

The reference item sodium benzoate was completely biodegraded within 7 days of exposure,

confirming suitability of the activated sludge.

In the toxicity control, containing the test item, the reference item sodium benzoate and

activated sludge (inoculum), the initial DOC decreased by 47% within 14 days of exposure.

Thus, according to the test guidelines the test item can be assumed to be not inhibitory to

activated sludge because degradation was >35Y0within 14 days.