Tetrakis(phenylmethyl)thioperoxydi(carbothioamide)

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Remarks:

Information from migrated NONS file, as per inquiry number 06-2119987039-24-0000 ,permission to refer granted by ECHA

Qualifier:

according to guideline

Guideline:

EU Method C.5 (Degradation: Biochemical Oxygen Demand)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Remarks:

Information from migrated NONS file, as per inquiry number 06-2119987039-24-0000 ,permission to refer granted by ECHA

Details on inoculum:

Activated sludge was obtained from the rwzi Nieuwgraaf in Duiven (1988-08-18). The rwzi Nieuwgraaf is a domestic sewage treatment plant.
The activated sludge was preconditioned as described in the EEC protocol (4.1.).

Duration of test (contact time):

28 d

Parameter followed for biodegradation estimation:

CO2 evolution

Reference substance:

acetic acid, sodium salt

Key result

Value:

ca. 2

Sampling time:

28 d

Remarks on result:

other: Information are given only as far as they were made available by ECHA (see data access for details)

Details on results:

Points of degradation plot (test substance):

0 % degradation after 3 d
0 % degradation after 6 d
0 % degradation after 10 d
0 % degradation after 17 d
0 % degradation after 21 d
1 % degradation after 27 d
2 % degradation after 28 d

Results with reference substance:

Points of degradation plot (reference substance):

35 % degradation after 3 d
68 % degradation after 6 d
77 % degradation after 10 d
80 % degradation after 17 d
81 % degradation after 21 d
82 % degradation after 27 d
82 % degradation after 28 d

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

TBzTD is not biodegraded in the sturm test and, therefore should not be classified as readily biodegradable.

Executive summary:

TBzTD is not biodegraded in the modified Sturm test according to Directrive EEC 84/488/EE, Part C. Methods for the determination of ecotoxicity, C. 5 Degradation biotic degradation: Modified Sturm test. Lack of ready biodegradation does not mean that TBzTD is recalcitrant in nature. Firstly, the water insolubility and secondly the stringency of the test procedures could account for the recalcitrance of TBzTD in the Sturm test. TBzTD is probably not toxic in the Sturm test because the endogenous carbon dioxide production is hardly or not affected by TBzTD.

Description of key information

TbzTD is not readily biodegradable according to a study following the EU method C.5 (2% biodegradation after 28d).

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

TBzTD is not biodegraded in the modified Sturm test according to Directrive EEC 84/488/EE, Part C. Methods for the determination of ecotoxicity, C. 5 Degradation biotic degradation: Modified Sturm test. Lack of ready biodegradation does not mean that TBzTD is recalcitrant in nature. Firstly, the water insolubility and secondly the stringency of the test procedures could account for the recalcitrance of TBzTD in the Sturm test. TBzTD is probably not toxic in the Sturm test because the endogenous carbon dioxide production is hardly or not affected by TBzTD.