1,1'-(methylenedi-4,1-phenylene)bis(3-butylurea)

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:

2000-10-11 to 2001-01-16

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

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Analytical purity: 97.4 %
Lot/batch No.: July 30, 1999

Analytical monitoring:

not specified

Details on sampling:

Preparation of test solutions:
In order to improve the substance dispersing in water, the test substance was ground down to very fine particles using a mortar and pestle before weighing. As the solubility of the test substance in Water is very low, test solutions at 31.6 and 100 mg/L were prepared by direct addition of the test substance in the test vessels. Test solutions at 1, 3.13 and 10 mg/L were prepared by means of a suspension at 20 mg/L in dechlorinated water because test substance quantities necessary for direct addition to the test flasks were too low to be accurately weighed (< 10 mg). The suspension was agitated during 8 minutes. Test solutions (1, 3.16 and 10 mg/L) were prepared immediately by further dilution of the suspension, maintained under agitation, with dechlorinated water.

Vehicle:

no

Details on test solutions:

The test solutions were prepared as follows:
- two control solutions: activated sludge in dechlorinated water to obtain a final sludge concentration of 1.6 g/L,
- five test substance solutions: activated sludge in dechlorinated water (at 1.6 g/L) and test substance (to obtain final concentrations of 1, 3.16, 10, 31.6 and 100 mg/L),
- three reference substance (3,5-dichlorophenol) solutions: activated sludge in dechlorinated water (at 1.6 g/L) and reference substance (to obtain final concentrations of 4, 12 and 36 mg/L).

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Type: Activated sludge collected from a water treatment works containing effluent from a predominantly domestic origin;
Origin: The water treatment plant Emereaude (SIARR) (76141 Petit-Quevilly, France);

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Hardness:

280 ± 20 mg/L as CaCO3

Test temperature:

20 ± 2 °C

pH:

6.0 - 8.0

Dissolved oxygen:

Not indicated

Salinity:

Not indicated

Nominal and measured concentrations:

Nominal concentrations: 1; 3.16; 10, 31.6; 100 mg/L of test substance; inoculum: 1.6 g/L;
Measured concentrations: Analytical measurement was not performed.

Details on test conditions:

Environmental conditions during the test:
Temperature: between 20 and 22 °C;
Illumination: no special precautions were taken;
Dilution water: dechlorinated tap water was used, with a hardness of 280 ± 20 mg/L as CaCO3;
Duration of test: 3 hours;
Aeration: air was bubbled through each solution at the rate of 0.5 to 1 L/min until the start of oxygen concentration measurement;
Test item concentrations: 1; 3.16; 10, 31.6; 100 mg/L of test substance; inoculum: 1.6 g/L;

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

Validity criteria:
As the difference between the two controls was below 15 % and the EC50 of 3,5-dichlorophenol was between 35 and 30 mg/L, the test was therefore considered valid.
Determination of the EC50:
Respiration rates of the test and reference solutions are presented in the table (See Sect. " Remarks on results incl. tables and figures")
The respiration rate of the test solution of highest concentration (100 mg/L) was equivalent to the respiration of the first control (i.e. these rates were within 15 % of each other). Therefore, the oxygen consumption rate of the for other test solutions (1 to 31.6 mg/L) was not determined.
The EC50, based on nominal concentrations, were as follows:
- Test substance: 3-hour EC50 (mg/L): > 100;
- Reference substance: 3-hour EC50 (mg/L): 10.8 (95 % confidence limits (mg/L): 8.87 - 13.1;

Results with reference substance (positive control):

Reference substance: 3-hour EC50 (mg/L): 10.8

Reported statistics and error estimates:

Reference substance: 3-hour EC50 95 % confidence limits (mg/L): 8.87 - 13.1;

Respiration rates of the test and reference solutions are presented in the table.

Table: Respiration rate in mg O₂-L^-1.h^-1. 

	Concentration (mg/L)	Respiration rate in mg O2-L^-1.h^-1.	Percent inhibition (%)
Control 1	0	42.0
Control 2	0	45.0
Reference substance	4	34.8	20
	12	19.5	55
	36	7.5	83
PATE HAT SECHEE	1	ND
	3.16	ND
	10	ND
	31.6	ND
	100	46.5	0

 

ND: not determined

Validity criteria fulfilled:

yes

Conclusions:

HAT ISO was tested for toxicity to bacteria in a 3-hour activated sludge respiration inhibition test. The EC50 of the test item HAT ISO was found to be > 100 mg/L. HAT ISO is considered as non-toxic for aquatic microorganisms. No classification and labelling for aquatic toxicity is required according to Regulation 1272/2008/EEC (CLP).

Executive summary:

HAT ISO was tested for toxicity to bacteria in a 3-hour activated sludge respiration inhibition test.

The EC50, based on nominal concentrations, were as follows:

- Test substance: 3-hour EC50 (mg/L): > 100;

- Reference substance: 3-hour EC50 (mg/L): 10.8

(95 % confidence limits (mg/L): 8.87 - 13.1);

HAT ISO is considered as non-toxic for aquatic microorganisms.

Description of key information

HAT ISO was tested for toxicity to bacteria in a 3-hour activated sludge respiration inhibition test.

The EC50, based on nominal concentrations, were as follows:

- Test substance: 3-hour EC50 (mg/L): > 100;

- Reference substance: 3-hour EC50 (mg/L): 10.8

(95 % confidence limits (mg/L): 8.87 - 13.1);

HAT ISO is considered as non-toxic for aquatic microorganisms.