Di(benzothiazol-2-yl) disulphide

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:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Results with reference substance:

62 % degradation of aniline within 28 days

Interpretation of results:

not readily biodegradable

Conclusions:

For 2,2'-disulfanediylbis(1,3-benzothiazole) 0 % degradation within 28 days was observed and is hence classified as not readily biodegradable.

Executive summary:

For 2,2'-disulfanediylbis(1,3-benzothiazole) 0 % degradation within 28 days was observed. The test was conducted following the OECD-Guideline 301 C-modified MITI Test. 2,2'-disulfanediylbis(1,3-benzothiazole) is hence classified as not readily biodegradable (Bayer AG, 1988).

Description of key information

For 2,2'-disulfanediylbis(1,3-benzothiazole) 0 % degradation within 28 days was observed. The test was conducted following the OECD-Guideline 301 C-modified MITI Test. 2,2'-disulfanediylbis(1,3-benzothiazole) is hence classified as not readily biodegradable (Bayer AG, 1988). In the EU-risk assessment for CBS (CAS: 95-33-0), information regarding the biodegradability of the potential metabolites of MBTS, such as MBT, BT, BTon, and MeSBT, is also summarized and discussed. The described metabolites are also not readily biodegradable. Only when the inoculi were adapted under special conditions, certain level of degradation of MBT, BT, BTon, and MeSBT was observed. Such processes are expected in biological treatment plant, but not in the environment.

Additional information

No respiration inhibition on activated sludge is expected, because the test concentration (i.e. 100 mg/l) of MBTS is much lower than the effective concentrations, such as an 3h-EC50 >10000 mg/l for MBTS.