3-[[3-(dimethylamino)propyl]amino]propiononitrile

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:

The study was conducted on 22 April 2016

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))

Version / remarks:

2010

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark

Analytical monitoring:

no

Details on sampling:

N/A

Vehicle:

no

Details on test solutions:

In the range-finding test, activated sewage sludge micro-organisms were exposed to a series of nominal test concentrations of 10, 100 and 1000 mg/L. The test item was dissolved directly in water.
A nominal amount of test item (2500 mg) was dissolved in water and the volume adjusted to 1 liter to give a 2500 mg/L stock solution from which dilutions were made to give 250 and 25 mg/L stock solutions. An aliquot (200 mL) of the 25 mg/L stock solution was dispersed with synthetic sewage (16 mL), activated sewage sludge (250 mL) and water, to a final volume of 500 mL, to give the required concentration of 10 mg/L. Similarly, aliquots (200 mL) of the 250 mg/L and 2500 mg/L stock solutions were used to prepare the test concentrations of 100 and 1000 mg/L. The 1000 mg/L test concentration was prepared in triplicate. The volumetric flasks containing the stock solutions were inverted several times to ensure homogeneity.
The pH of the test item stock solutions were measured using a Hach HQ40d Flexi handheld meter (see Table 1) and adjusted to between pH 7.0 to pH 8.0 if necessary.
The exposure conditions for each flask were as described below.
The control group was maintained under identical conditions but not exposed to the test item.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Preparation of Inoculum
The activated sewage sludge sample was maintained on continuous aeration in the laboratory at a temperature of approximately 21 ºC and was used on the day of collection. The pH of the sample was 7.1 measured using a Hach HQ40d Flexi handheld meter. Determination of the suspended solids level of the activated sewage sludge was carried out by filtering a sample (100 mL) of the activated sewage sludge by suction through a pre-weighed GF/A filter paper* using a Buchner funnel which was then rinsed 3 times with 10 mL of deionized reverse osmosis water and filtration continued for 3 minutes. The filter paper was then dried in an oven at approximately 105 ºC for at least one hour and allowed to cool before weighing. This process was repeated until a constant weight was attained. 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

Test temperature:

19-20”C

pH:

7.4-8.1

Dissolved oxygen:

6.3-7.2 mg O2/L

Details on test conditions:

Preparation of Test System
At time "0" 16 mL of synthetic sewage was diluted to 250 mL with water and 250 mL of inoculum added in a 500 mL conical flask (first control). The mixture was aerated with clean, oil-free compressed air via narrow bore glass tubes at a rate of 0.5 to 1.0 liter per minute. Thereafter, at 15 minute intervals the procedure was repeated for the second control followed by the reference item vessels with appropriate amounts of the reference item being added. The test item vessels were prepared as described in Section 3.3.1.1. Finally two further control vessels were prepared.
The test was conducted under normal laboratory lighting in a temperature controlled room at measured temperatures of between 19 and 20 ºC.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

not determinable

Details on results:

The dissolved oxygen concentrations after 30 minutes contact time in all vessels were above 60 to 70% of the dissolved oxygen saturation level of 8.9 mg O2/L.
No statistically significant toxic effects were shown at all of the test concentrations employed. It was therefore considered justifiable not to perform a definitive test.
It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/L.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
:

Inhibition of Respiraton Rate:

	3-[[3-(Dimethylamino)propyl]amino]propanenitrile (TK2710)		3,5 -dichlorophenol
	ECx (3 hours) (mg/L)	95% Confidence Limits (mg/L)	ECx (3 hours) (mg/L)	95% Confidence Limits (mg/L)
EC10	>1000	-	1.2	-
EC20	>1000	-	1.8	-
EC50	>1000	-	6.6	4.9 -8.8
EC 80	<1000	-	24	-
NOEC	1000	-	-	-

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.

Executive summary:

A study was performed to assess the effect of the test item on the respiration of activated sewage sludge. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2010) No. 209 "Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation)".

Methods

Activated sewage sludge was exposed to an aqueous solution of the test item at concentrations of 10, 100 and 1000 mg/L (3 replicates of the 1000 mg/L test concentration) for a period of 3 hours at temperatures of between 19 and 20 °C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 hours contact time and compared to data for the control and a reference item, 3,5-dichlorophenol.

Results

The effect of the test item on the respiration of activated sewage sludge 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.

It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/L.

The reference item gave a 3-Hour EC50 value of 6.6 mg/L, 95% confidence limits 4.9 to 8.8 mg/L.

Description of key information

The toxoicity of Aradur 1019 to microorganisms was deteremined according to OECD test guideline 209, "Activated Sludge Respiration Inhibition Test".

The results is reported to be EC50 (3h) >1000mg/l

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L