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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19 January to 21 February 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
not specified
Qualifier:
according to guideline
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
Deviations:
not specified
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
The inoculum was derived from surface waters collected in the near area of Pau, France and receiving predominantly domestic sewage.
The freshly collected sample of surface water was previously pre-conditioned to the experimental conditions under aerobic conditions for 6 days in
the mineral medium at the test temperature: 800 mL of surface water were added with 1.0 mL of the stock solutions A, B and C and 0.1 mL of the stock solution D (See § 3.2) and the volume was made to 1 L.
The resulting solution was maintained under strong aeration and agitation at 20 ± 1°C for 6 days.
The pre-conditioned inoculum was further used at a rate of 2 mL/L of medium.
The suspended solids were measured to represent 3.8 µg/L.
Duration of test (contact time):
28 d
Initial conc.:
3.38 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST DESIGN AND PREPARATION
Test design
Parallel groups of 250 mL BOD bottles were prepared of sufficient number to allow assessments every 3-4 days throughout the 28-day incubation
period for each of the following experimental series:
Blank group: mineral medium alone with inoculum (duplicate determinations),
Test item group: 2-5 mg/L test solution in mineral medium with inoculum (duplicate determinations),
Reference group: 2-5 mg/L aniline solution in mineral medium with inoculum (duplicate determinations),
Toxic control group: solution containing 2-5 mg/L of each the test substance and aniline in mineral medium, with inoculum (single determinations).

Preparation of the bottles
The 250 mL BOD bottles were thoroughly cleaned before use using 5-10 mL of a wash solution (2.5 g iodine plus 12.5 g potassium iodide per litre of 1% w/v sulphuric acid). The bottles were shaken to coat the bottle walls and left to stand for 15 min. The wash solution was poured off and the bottles were thoroughly rinsed with tap water and finally demineralised water.

Preparation of the experimental solutions
Blank: The BOD bottles received 300 mL of mineral medium.
Test item: A stock solution was prepared using 50.2 mg of the test sample for 500 mL of mineral medium. The BOD bottles received each 16 mL of the stock solution and the volumes were made to 300 mL with the mineral medium.
Aniline: A stock solution was prepared using 126.2 mg of Aniline for 20 mL of water. The BOD bottles received each 0.1 mL of the stock solution and
the volumes were made to 300 mL with the mineral medium.
Toxic control: The BOD bottles received 16 mL of the test item stock solution + 0.1 mL of the aniline stock solution and the volumes were made to
300 mL with the mineral medium.
In each case the BOD bottles received each 0.6 mL of pre-conditioned inoculum.
Reference substance:
aniline
Key result
Parameter:
% degradation (O2 consumption)
Value:
96.3
Sampling time:
3 d
Details on results:
The calculated biodegradation exceeded 100 % after day 3. The reason was not identified.
Results with reference substance:
97.6% degraded at 24 days
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The pass-level for ready biodegradation was reached within the first three days of testing.
Calcium tartrate was considered as easily biodegradable.
Executive summary:

 

Phytosafe Study Number

10-27-077-ES

Study

Ready biodegradability of Calcium tartrate - Closed-bottle test (CEE C4.e)

Test item

Calcium tartrate

Batch No.Camp 09.10

Theoretical oxygen demand

ThOD =g/g

Nominal test item concentration

3.62 mg/L (1.23 mg ThOD/L)

Test dates

January 19 to February 21, 2011

 

Results

The pass-level for ready biodegradation was reached within the first three days of testing.

Calcium tartrate was considered as easily biodegradable.


Description of key information

Ready biodegradability of Calcium tartrate was determined according to OECD Guideline 301 D. The pass-level for ready biodegradation was reached within the first three days of testing. Calcium tartrate was considered as easily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information