Fatty acids, C18 unsat, reaction products with diethylenetriamine

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:

08-02-2010 - 11-02-2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test performed under GLP according guidelines, all quality criteria were met

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

not required

Vehicle:

no

Details on test solutions:

The tall oil diethylenetriamine imidazoline stock solution was prepared by stirring 0.48 g tall oil diethylenetriamine imidazoline in 480 mL of deionized water. The tall oil diethylenetriamine imidazoline stock solution was a homogenous suspension (light turbidity).
pH stock solution = 10.0

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Unadapted secondary activated sludge was obtained (08-02-2010) from the WWTP Nieuwgraaf in Duiven. The WWTP Duiven is an activated sludge plant treating predominantly domestic wastewater. Prior to use the activated sludge was homogenized with a syringe. The dry weight of the homogenized activated sludge was determined and subsequently concentrated by settlement to the required dry weight concentration. The dry weight of the activated sludge in the incubation vessels was 1.7 g/L.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

Temperature varied from 20.1 to 21.3°C.

pH:

The pH of the reaction mixtures after the incubation period ranged from 7.2 to 7.6.

Dissolved oxygen:

aerobic during test

Details on test conditions:

-The test was performed in 250 to 300 ml Erlenmeyers.
-The homogenized activated sludge was incubated in a shaking water bath (100 rpm, 20°C) for 3 hours with various concentrations of the test
compound and synthetic sewage.
-Synthetic sewage was added to the activated sludge (1.6 ml on a total volume of 50 ml).
Synthetic sewage contained per liter: 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
-Different concentrations (spaced by a factor two) of test compound and reference compound where added using stock solutions of respectively 1.0 g/L and 0.5 g/L.
-Tap-water was used to fill up the total test volume to 50 mL.
- The dry weight concentration of the activated sludge in the test was 1.7 g/L
-The tested concentrations of the reference compound 3,5-dichlorophenol where: 2.5 mg/L, 5.1 mg/L,10.2 mg/L, 20.3 mg/L and 40.6 mg/L
-The tested concentrations of tall oil diethylenetriamine imidazoline where: 20 mg/L, 40 mg/L, 80 mg/L, 160 mg/L, 320 mg/L and 640 mg/L
-Controls without test substance (or reference compound) are measured at the beginning and at the end of the test
-The inhibitory effect of the test substance/reference compound is expressed as a percentage of the mean of the two control respiration rates.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

59 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Test material is a UVCB with 100% purity

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

175 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: with 95% confidence limits of 92 and 473 mg/L

Details on results:

Test conditions
The pH of the reaction mixtures after the incubation period ranged from 7.2 to 7.6. Temperature varied from 20.1 to 21.3°C. These conditions allowed respiration of the activated sludge used.

Validity of the test
The validity of the test is demonstrated by two criteria. First, the control respiration rates were within 15% of each other and secondly, the EC50 of the reference compound was 9 mg/L which is within the prescribed range of 5 to 30 mg/L .

Activated sludge respiration inhibition test
The inhibitory effect of tall oil diethylenetriamine imidazoline at a particular concentration is expressed as a percentage of the two controls. From the results EC values were calculated. The EC50 of tall oil diethylenetriamine imidazoline for activated sludge after 3 hours contact time is 175 mg/L
with 95% confidence limits of 92 and 473 mg/L. The EC10, EC20 and EC80 are 59, 85 and 360 mg/L, respectively.

Results with reference substance (positive control):

The EC50 of the reference compound was 9 mg/L at a contact time of 3 hours, respectively. These EC50 values is within the prescribed range of 5 to 30 mg/L.

Reported statistics and error estimates:

The EC values were computed from the best-fitted line (least square method)
through the points given by the probit of the percentage inhibition and the logarithm of the concentration of the substance. All computations were performed with the program TOXCALCTM(Tidepool Scientific Software 1994-1999).

Validity criteria fulfilled:

yes

Remarks:

The validity of the test is demonstrated by two criteria. First, the control respiration rates were within 15% of each other and secondly, the EC50 of the reference compound was 9 mg/L which is within the prescribed range of 5 to 30 mg/L .

Conclusions:

Test performed under GLP according guidelines. The test is valid as shown by the EC50of the reference compound, 3,5-dichlorophenol (9 mg/L
contact time 3 hours ) and the control respiration rates which are within 15% of each other.
The EC50 of tall oil diethylenetriamine imidazoline for activated sludge after 3 hours contact time is 175 mg/L with 95% confidence limits of 92 and
473 mg/L. The EC10, EC20 and EC80 are 59, 85 and 360 mg/L, respectively.
Tall oil diethylenetriamine imidazoline is therefore considered not harmful to activated sludge.

Executive summary:

In order to predict effects of chemicals in the environment and in biological waste water treatment plants, an activated sludge respiration inhibition test was performed. The toxicity to activated sludge was determined in accordance with OECD Test Guideline 209, and in compliance with the OECD principles of Good Laboratory Practice.

The test is valid as shown by the EC₅₀of the reference compound, 3,5-dichlorophenol (9 mg/L) and the control respiration rates which are within 15% of each other.

The toxicity of tall oil diethylenetriamine imidazoline to activated sludge was determined at a contact time of 3 hours, using various concentrations of the test substance. The inhibitory effect of tall oil diethylenetriamine imidazoline at a particular concentration is expressed as a percentage of the two controls. The EC₅₀of tall oil diethylenetriamine imidazoline for activated sludge after 3 hours contact time is 175 mg/L with 95% confidence limits of 92 and 473 mg/L. The EC₁₀, EC₂₀and EC₈₀are 59, 85 and 360 mg/L, respectively.

Tall oil diethylenetriamine imidazoline is therefore considered not harmful to activated sludge.

 

Description of key information

There is one report available for this endpoint. The  EC50 for microorganisms as observed in a three hour OECD 209 test for 1H-Imidazole-1-ethanamine, 4,5-dihydro-, 2-nortall-oil alkyl derivs. (CAS no 68442-97-7) is 175 mg a.i./L and the EC10 is 59 mg a.i./L

Key value for chemical safety assessment

EC50 for microorganisms:

175 mg/L

EC10 or NOEC for microorganisms:

59 mg/L

Additional information

The substance is a UVCB with 100% purity  (no solvents)