1,3-bis(2,4,4-trimethylpentan-2-yl)trisulfane

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 - 16 February, 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

not specified

Details on sampling:

not specified

Vehicle:

no

Test organisms (species):

other: A mixed population of activated sewage sludge micro-organisms

Details on inoculum:

The suspended solids concentration was equal to 3.0 g/L.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Hardness:

not specified

Test temperature:

20 - 21 °C

pH:

at 0 hours: 7.7 - 7.8
at 3 hours: 7.6 - 7.7

Dissolved oxygen:

at 0 hours: 5.2 - 6.0 mg O2/L
at 3 hours: 1.8 - 2.3 mg O2/L

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

Nominal Concentration: 10, 100 and 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: conical flask
- No. of vessels per concentration (replicates): 1 x 10 mg/L; 1 x 100 mg/L and 3 x 1000 mg/L
- No. of vessels per control (replicates): 4


TEST MEDIUM / WATER PARAMETERS
- Particulate matter:
Synthetic Sewage
16 g - Peptone
11 g - Meat extract
3 g - Urea
0.7 g - NaCl
0.4 g - CaCl2.2H2O
0.2 g - MgSO4.7H2O
2.8 g - K2HPO4

OTHER TEST CONDITIONS
- Adjustment of pH: yes, with 1.0 M NaOH

TEST CONCENTRATIONS
- Range finding study
Test concentrations: nominal test concentrations of 10, 100 and 1000 mg/L

Reference substance (positive control):

yes

Remarks:

A reference item - 3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/L

Key result

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Key result

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

ca. 1 000 mg/L

Results with reference substance (positive control):

- Results with reference substance valid? yes

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test item on the respiration of activated sewage sludge micro-organisms gave a 3-Hour EC50 value of greater than 1000 mg/L.
The No Observed Effect Concentration (NOEC) after 3 hours exposure was 1000 mg/L.

Description of key information

Inhibition of Respiration Rate (3 hours)

EC₅₀ > 1000 mg/L

NOEC = 1000 mg/L

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

An Activated Sludge Respiration Inhibition Test (ASRIT) was conducted (Envigo Research Limited, XH03GB, 2017) to determine the effect of DAIBUBE IS-30 on microorganisms. The test was conducted according to OECD test guideline 209, and in compliance with GLP.

A mixed population of activated sludge was taken from a sewage treatment plant. Cultures were exposed to DAIBUBE IS-30 at concentrations 10, 100 and 1000 mg/L for 3 hours in the preliminary test only. The dissolved oxygen concentrations after 30 minutes contact time in all vessels were above 60% of the dissolved oxygen saturation level of 8.9 mg O2/L. It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/L.

The effect of the test item on the respiration of activated sewage sludge micro-organisms gave a 3-Hour EC50 value of greater than 1000 mg/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was 1000 mg/L.