O-isopropyl ethylthiocarbamate

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:

16 AUG 2012 - 13 SEP 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

secondary effluent from a municipal wastewater treatment plant in Usserød, Denmark, wihich predominantly receives domestic sewage

Duration of test (contact time):

28 d

Initial conc.:

2.2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The study was performed with aerobic activated sludge from a wastewater treatment plant (Usserød, Denmark). The necessary volume of the test medium with minerals was prepared. The medium was aerated to an initial concentration of approx. 9 mg O²/L and inoculated with 0.5 mL secondary effluent/L

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

3.3

Sampling time:

7 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

2.4

Sampling time:

14 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

6.7

St. dev.:

2.1

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

2.1

St. dev.:

1

Sampling time:

28 d

Key result

Parameter:

COD

Value:

200 other: mg/l

Biodegradation of test substance and reference substance tested seperately and in combination.

TimeDays	Test product "Danafloat TM 262 (IPETC)" % of ThOD	Activity controlsodium benzoate  % of ThOD	Toxicity control "Danaflost TM 262 (IPETC)+ sodium benzoate% of ThOD
7	3.3	65.2	31.0
14	2.4	72.6	35.4
21	6.7	76.9	36.5
28	2.1	71.2	35.1

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance was found to be not biodegradable under the test conditions within the 28-day exposure period.

Executive summary:

Biodegradation test was done according to OECD Guideline 301D. Test substance was tested in a concentration of 2.2 mg/L and reference substance in a concentration of 2.0 mg/L. The substance was found to be not biodegradable under the test conditions within the 28-day exposure period. The oxygen consumption in the activity control showed that the activity of the inoculum was satisfactory. In the toxicity control containing both the test substance and the reference item sodium benzoate no inhibitory effect on microorganisms in inoculum was observed. In the procedure controls the reference item sodium benzoate was readily biodegraded by an average of 72.6 % within 14 days of exposure; thus confirming suitability of the activated sludge.

Description of key information

Biodegradation test was done according to OECD Guideline 301D. Test substance was tested in a concentration of 2.2 mg/L and reference substance in a concentration of 2.0 mg/L. The substance was found to be not biodegradable under the test conditions within the 28-day exposure period. The oxygen consumption in the activity control showed that the activity of the inoculum was satisfactory. In the toxicity control containing both the test substance and the reference item sodium benzoate no inhibitory effect on microorganisms in inoculum was observed. In the procedure controls the reference item sodium benzoate was readily biodegraded by an average of 72.6 % within 14 days of exposure; thus confirming suitability of the activated sludge.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater