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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:
April-July 2016
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
according to
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
not applicable
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
- Test item name: RCX 15-116
- Batch number: 15047AE2
- Other name(s): NPAL
- Appearance/colour: solid/whitish
- Chemical name: aluminium-N-nitrosophenylhydroxylamine (NPAL)
- CAS number: 15305-07-4
- Purity analysed: 99.1 %
- Molecular weight 438.3 g/mol
- Issue date of certificate: 08 Feb 2016
- Expiry date: 30 Nov 2016
- Stability: instable after repeated contact to air and / or light, undergoes hydrolysis
- Storage conditions: room temperature, protected from light
Oxygen conditions:
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
A microbial community serving as Inoculum at a concentration of 30 mg/L was obtained from a municipal sewage treatment plant treating predominantly domestic sewage.
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
During a 28 day period the O2 demand of the test item and several controls was evaluated in a climate controlled and closed system containing a CO2 absorbing agent, an electro-chemical oxygen generator and a switching manometer.
Treatment groups evaluated:
• Test item group (test item and inoculum)
• Procedure control group (reference item and inoculum)
• Inoculum control group (inoculum)
• Toxicity control group (test item, reference item and inoculum)
Reference substance:
benzoic acid, sodium salt
100 mg/L
Key result
% degradation (TOC removal)
Sampling time:
28 d
Validity criteria fulfilled:
Interpretation of results:
not readily biodegradable
RCX 15-116 cannot be considered to be readily biodegradable according to OECD guideline 301 F.
Executive summary:

The ready biodegradability of RCX 15-116was assessed with the Manometric Respirometry Test according to OECD Guideline 301 F.RCX 15-116was tested at a nominal concentration of 100 mg/L.The following biodegradation was determined at the end of the 28-d period:

*        RCX 15-116 (100 mg/L):                   2.8 %

*        Sodium benzoate (100 mg/L):           92.7 %

Since the pass value of > 60 % was not reached within 28 days RCX 15-116 cannot be considered to be readily biodegradable according to OECD guideline 301 F. RCX 15-116 had no inhibitory effect on activated sludge microorganisms at the tested concentration of 100 mg/L.

Description of key information

The test substance is not readily biodegradable in the Manometric Respirometry Test (OECD 301 F).

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information