di-p-tolyl(2,4,6-trimethylbenzoyl)phosphine oxide

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:

2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

Inoculum concentration: 25.0 mg/L
Temperature 16.2 – 21.1 °C without direct lighting
Duration 28 days

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

IC (inorganic carbon)

Remarks:

The test was performed with a nominal start concentration of 20 mg organic carbon/L of the test item.

Parameter followed for biodegradation estimation:

CO2 evolution

Parameter:

% degradation (test mat. analysis)

Value:

0

Sampling time:

28 d

9 RESULTS AND VALIDITY

9.1 Results for the Test Item (di-p-tolylphosphoryl)(mesityl)methanone
• The test item (di-p-tolylphosphoryl)(mesityl)methanone is considered as “not readily biodegradable“.
• The degree of biodegradation reached 0 % after 28 days.
• The 10-day-window was not detected.
• Degradation missed 60 % within 28 days, too. Therefore, the test item is considered as “not ultimately biodegradable within 28 days”, as well.
• Abiotic degradation was not observed.

9.2 Validity

All validity parameters and values are presented in the following table:

Table 9.2‑a        Validity

Parameter	Criterion	Found	Assessment
IC content of test item solution in medium	< 5% of TC	0 %	valid
CO2 emitted by the controls	< 70 mg/L	9.4 mg/L	valid
Difference within replicates	< 20%	7.7 %	valid
Degradation of positive control ≥ 60%	≤ 14 days	8 days	valid
Degradation in the toxicity flask on day 14	> 25%	37.3 %	non - toxic

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

For the test item (di-p-tolylphosphoryl)(mesityl)methanone no biodegradation was observed after 28 days. The 10-day window could not be determined. The criterion of reaching 60% of degradation after 28 days is not met. The test item (di-p-tolylphosphoryl)(mesityl)methanone is therefore considered as “not readily biodegradable” and not ultimately biodegradable, within 28 days.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater