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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:
22 January 2018 to 28 November 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
Name: phosphoric acid, methyl ester, compounds with branched dodecylbenzenamine
Synonym: dodecylaniline salt of methyl acid phosphates
CAS No.: 1412893-77-6
Purity: >94%
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
The activated sludge used for this study was obtained from the Wareham Wastewater Treatment Plant, Wareham, Massachusetts, which receives primarily domestic waste.

The soil and sediments were suspended in 1 L of Weweantic River water by hand shaking for one minute and the suspension was then filtered through glass wool. This soil/sediment inoculum was determined to contain no solids. A 3.0-mL aliquot of the soil/sediment inoculum was added to each test vessel containing mineral medium and 6.0 mL of activated sludge.
Duration of test (contact time):
28 d
Initial conc.:
10 other: mg C/L
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
Each test unit consisted of a 4-L glass bottle with a rubber stopper into which one stainless steel needle with a Luer-Lok connection and two pieces of glass tubing were inserted. Prior to test initiation, the test vessels were washed with detergent and rinsed with water. The test vessels were then acid washed with 50% nitric acid and rinsed repeatedly with reagent grade water. The stainless-steel needle was extended through the stopper into the test solution serving as a sampling port for solution samples. A rubber policeman cap was used to cover the top of the sample port. The glass tubing provided the inlet and outlet ports for air exchange. CO2 free air was pumped under positive pressure through a hydration flask before entering the test system. The outlet port of each system was connected to two CO2 effluent gas traps, the first consisting of 200 mL of 0.2 N potassium hydroxide (KOH) and the second trap containing 100 mL of 0.2 N KOH. The test vessels were identified with the study number, replicate (A or B), and treatment type. Each test vessel was placed on a magnetic stir plate located in a dark environmental chamber set to maintain a temperature of 22 ± 2 °C.
Reference substance:
benzoic acid, sodium salt
Remarks:
10 mg C/L
Key result
Parameter:
% degradation (CO2 evolution)
Value:
0
Sampling time:
28 d
Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
Not readily biodegradable.
Executive summary:

Based on the extent of CO2 evolution during this study, test material cannot be classified as readily biodegradable by the criteria set forth in OECD Guideline 301B since it did not achieve 60% CO2 evolution within a 10-day window of reaching 10% biodegradation.  

Description of key information

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:
freshwater

Additional information