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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:
From October 12, 2017 to January 04, 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)
Deviations:
no
Qualifier:
according to
Guideline:
other: EN ISO 10634:1995 – Guidance for the preparation and treatment of poorly water soluble organic compounds for the subsequent evaluation of their biodegradability in an aqueous medium
Deviations:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
other: Aerobic sludge: mixed treatment plant of urban (about 66%) and industrial (about 34%) liquid sewage
Details on inoculum:
Method of mud sampling
Biodegradability of a substance is based on different parameters, and among them composition and concentration of bacterial biomass play an important role. For the preparation of the inoculum a sample of aerobic sludge has been selected by the mixed treatment plant of urban (about 66%) and industrial (about 34%) liquid sewage situated at San Rocco - Monza (MB), Italia. The plant of treatment is managed by “BRIANZACQUE SRL (Monza)”.

Mud preparation
In the laboratory the sampled muds, have been mixed and let settle, keeping them in aerobic conditions.
The mud samples, before their use, have been analysed to check its ability to form colony units. Then it has been centrifuged, washed and analyzed to quantify the suspended solids concentration for the inoculum preparation. The inoculum was prepared in order to have a concentration of suspended solid of about 4 mg/L.
Duration of test (contact time):
ca. 28 d
Initial conc.:
ca. 23.39 mg/L
Based on:
TOC
Remarks:
nominal
Parameter followed for biodegradation estimation:
inorg. C analysis
Reference substance:
benzoic acid, sodium salt
Remarks:
Starting nominal concentration of 23.66 mg/L of organic carbon (TOC)
Key result
Parameter:
% degradation (inorg. C analysis)
Remarks:
Test substance
Value:
ca. 2
Sampling time:
28 d
Remarks on result:
other: Not readily biodegradable
Results with reference substance:
Percentage biodegradation of reference substance at 14 d was determined to be 80%, therefore the assay fulfilled the validity criteria.

Results

Quality criteria of the test are satisfied. The mean amount of TIC present in the blank controls at the end of the test is <3 mg C/L. The biodegradation percentage of the test substance during the test is summarized in the following table.The trend of the inorganic carbon and related biodegradation percentages (See table below - column % of biodegradation Reference substance + test substance) in the bottle contained both the test substance and the reference substance confirm the absence of inhibitory effect of the test substance on inoculum.

 

Check Point

(Days)

% Of Biodegradation of Reference Substance

% Of Biodegradation of Test Substance

% Of Biodegradation of Reference Substance+ Test Substance

0

0

0

0

1

1

1

3

7

80

1

-

14

80

0

-

21

83

0

-

28

85

2

45

35

79

1

-

42

83

1

-

49

87

3

-

56

88

5

50

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
Under study conditions, the test substance, iso and anteiso C10-40 AAP EDM-ES, was determined to be not readily biodegradable.
Executive summary:

A study was conducted to determine the ready biodegradability of the test substance, 'iso and anteiso C10-40 AAP EDM-ES' (active: 96%), according to the OECD Guideline 310, Ready Biodegradability – CO2 in sealed vessels (Headspace Test) method, in compliance with GLP. Aerobic sludge inoculum was prepared with mixed treatment plant of urban (66%) and industrial (34%) liquid sewage and in order to have a concentration of suspended solid of about 4 mg/L. In the study, for inoculum blanks, positive control (reference substance: sodium benzoate at 23.66 mg/L) and test substance (23.39 mg/L) groups, 29 inoculum bottles replica each, whereas for toxicity control (test and reference substances) group, 11 inoculum bottles replica were used. All treated samples were kept at the temperature of 20°C for 56 d. The calculation of biodegradation as total inorganic carbon (TIC) were determined at each sampling time (0, 1, 7, 14, 21, 28, 35, 42, 49 and 56 d) for the reference substance, test sample and blank. For toxicity control, calculation of biodegradability as total inorganic carbon (TIC) was determined on Day 1, 28 and 56. The trend of the inorganic carbon and related biodegradation percentages in the bottle contained both the test sample and the reference substance did confirm the absence of inhibitory effect of the test sample on inoculum. At 28 d, the biodegradability of the test substance was determined to be 2%. At 14 d biodegradability for reference substance was determined to be 80%. The mean amount of TIC present in the blank controls at the end of the test was <3 mg C/L. Based on the study results, the test has satisfied the all validity criteria. Under the study conditions, the test substance, 'iso and anteiso C10-40 AAPEDM-ES', was determined to be not readily biodegradable (Eurofins, 2018).

Description of key information

Based on the study results, the test substance, 'iso and anteiso C10-40 AAP EDM-ES' was determined to be not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

A study was conducted to determine the ready biodegradability of the test substance, 'iso and anteiso C10-40 AAP EDM-ES' (active: 96%), according to the OECD Guideline 310, Ready Biodegradability – CO2 in sealed vessels (Headspace Test) method, in compliance with GLP. Aerobic sludge inoculum was prepared with mixed treatment plant of urban (66%) and industrial (34%) liquid sewage and in order to have a concentration of suspended solid of about 4 mg/L. In the study, for inoculum blanks, positive control (reference substance: sodium benzoate at 23.66 mg/L) and test substance (23.39 mg/L) groups, 29 inoculum bottles replica each, whereas for toxicity control (test and reference substances) group, 11 inoculum bottles replica were used. All treated samples were kept at the temperature of 20°C for 56 d. The calculation of biodegradation as total inorganic carbon (TIC) were determined at each sampling time (0, 1, 7, 14, 21, 28, 35, 42, 49 and 56 d) for the reference substance, test sample and blank. For toxicity control, calculation of biodegradability as total inorganic carbon (TIC) was determined on Day 1, 28 and 56. The trend of the inorganic carbon and related biodegradation percentages in the bottle contained both the test sample and the reference substance did confirm the absence of inhibitory effect of the test sample on inoculum. At 28 d, the biodegradability of the test substance was determined to be 2%. At 14 d biodegradability for reference substance was determined to be 80%. The mean amount of TIC present in the blank controls at the end of the test was <3 mg C/L. Based on the study results, the test has satisfied the all validity criteria. Under the study conditions, the test substance, 'iso and anteiso C10-40 AAPEDM-ES', was determined to be not readily biodegradable (Eurofins, 2018).

[Type of water: freshwater]