Pentapotassium ({[(hydroxyphosphinato)methyl](phosphonatomethyl)nitroryl}methyl)phosphonate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to the appropriate OECD test guideline and in compliance with GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

A mixed population of activated sludge from the aeration stage of the Severn Trent Water Plc sewage treatment plant. The aerated sample was homogenised for 5 minutes and centrifuged to remove the suspended solids.

Duration of test (contact time):

28 d

Initial conc.:

1 450 mg/L

Based on:

other: liquid solution product

Details on study design:

TEST CONDITIONS
- Composition of medium: Direct dispersion in culture medium. The concentration, stability and homogeneity of the test material preparations were not analysed.

Test temperature: 24 °C

- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: 2 litre glass beakers. Agitation; by magnetic stirrers and compressed air via narrow bore glass tubes.

SAMPLING
- Sampling frequency: 0, 7, 14, 21, 27, 28 d

- Sampling method: 20 ml samples were withdrawn from each vessel and filtered through 0.45 µm disposable filters, the first 5 ml was discarded.

- Sample storage before analysis: Opaque plastic bottle, room temperature.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (DOC removal)

Value:

4

Sampling time:

28 d

Results with reference substance:

95% in 28d

Interpretation of results:

other: not readily biodegradable

Description of key information

Experimental studies of both ready biodegradation and inherent biodegradation are available for ATMP-N-oxide potassium salt. The ready biodegradation study is reliable and demonstrates that the substance is not readily biodegradable. The inherent biodegradation (Zahn-Wellens) result appears to show rapid and complete removal, but this study is disregarded for the purpose of chemical safety assessment on the basis of methodological deficiencies and pre-adaptation of the inoculum.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Based on the experimental evidence, ATMP-N-oxide potassium salt is not readily biodegradable. The removal seen in the pre-adapted inherent study is notable, but is not generally useable in the chemical safety assessment and is considered to be disregarded data of non-assignable reliability.