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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
other: OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
Remarks:
1: Dissolved Organic Carbon of Ultra Pure Water is no more controlled, in connection with the DOC control data base. 2: The study plan was signed on 21/11/11 when experimentation already began on 14/11/11. These deviations have no effect on the validity
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
The inoculum came from the activated sludge of the biological wastewater treatment plant from Abidos (France, 64). The effluent, obtained 3 days before seeding the flasks, was centrifuged at approximately 20 °C for 10 min at 1000 g; the base was re-suspend ed in dilution water in order to keep the concentration unchanged with respect to the sample. The inoculum was preconditioned (aeration) until the flasks were inoculated. The amount of dry material in the inoculum, determined by desiccation at 105 °C until a constant weight is obtained, was 4.81 g/L.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
28 d
Hardness:
No data
Test temperature:
22°C
pH:
pH 7.4
Dissolved oxygen:
No data
Salinity:
Not relavant
Nominal and measured concentrations:
Nominal concentration 100 mg/L
Details on test conditions:
This test was performed according to OECD 301F with the following conditions:
A known volume of inoculated dilution water, containing 100 mg/L of the test item is stirred darkness in a reactor at a constant temperature of 22°C and at pH 7.4.
The degradation is followed by the analysis of the carbon dioxide produced over a period of 28 days by measuring the quantity of oxygen generated automatically by the SELUTEC BSBdigi automatic respirometer: the CO2 generated by the ultimate biodegradation process is fixed by the soda lime placed in the reactor’s capsule. A drop in pressure ensues, which is detected by the manometer and sent to the control unit. In return, this sends an electrical current into the oxygen generator, which generates electrochemically an amount of oxygen in proportion to the intensity of the electrical current. 25 mg of test item are poured in test flasks, corresponding to a theoretical O2 mass of 53.79 mg per flask (ThOD 2.1515 mg O2/mg).

A parent solution of sodium benzoate in the dilution water to 2.5 mg/mL, was used in a proportion of 10 mL for 250 mL of dilution water, i.e. 25 mg, corresponding to a theoretical O2 mass of 41.65 mg per flask (ThOD 1.67 mg O2/mg).

In the inhibition monitoring flask, equivalent quantities of test and reference items are introduced. For this flask, the corresponding theoretical mass of O2 is 95.44 mg per flask.

The flasks were installed in the respirometer where the stirring system was started. After a waiting period of approximately 0.5 hour, which is necessary to reach the thermal equilibrium of the solutions at a temperature of 22 ± 1°C, the aerated inoculum, preconditioned if required, is added to all the flasks that are then plugged.
Reference substance (positive control):
no
Duration:
28 d
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition of the biodegradation of the reference test item during a ready biodegradability test
Details on results:
COPPER DIBUTYLDITHIO CARBAMATE did not inhibit the micro-organisms as shown by the toxicity control flask where biodegradation percentage is already 38.5%, higher than 25% after 14 days.
Validity criteria fulfilled:
not applicable
Conclusions:
The toxicity of COPPER DIBUTYLDITHIO CARBAMATE on microorganisms was assessed in a ready biodegradability study performed according to OECD 301F guideline: NOEC = 100 mg/L
Executive summary:

The toxicity of COPPER DIBUTYLDITHIO CARBAMATE on microorganisms was assessed in a ready biodegradability study performed according to OECD 301F guideline: NOEC = 100 mg/L. The data obtained from the toxicity control used in this study indicates that the substance is not toxic to micro-organisms at the 100 mg/L concentration (NOEC = 100 mg/L)

Description of key information

The toxicity of COPPER DIBUTYLDITHIO CARBAMATE on microorganisms was assessed in a ready biodegradability study performed according to OECD 301F guideline: NOEC = 100 mg/L, i.e. no effect up to the water solubility limit. 

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
100 mg/L

Additional information

The toxicity of COPPER DIBUTYLDITHIO CARBAMATE on microorganisms was assessed in a ready biodegradability study performed according to OECD 301F guideline. The data obtained from the toxicity control used in this study indicates that the substance is not toxic to micro-organisms at the 100 mg/L concentration (NOEC = 100 mg/L)