Fats and Glyceridic oils, vegetable, winterized, reaction products with ammonia-ethanolamine reaction by-products

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:

13-01-2015 to 23-01-2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: test according to the guideline under GLP. Slight deviations of the oxygen concentration during the test did not affect the results

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Principles of method if other than guideline:

only the range-finding study was performed

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: direct addition to reversed osmosis water, followed by ultrasonication for 15 min. The solution was stirred magnetically for 24 hours at 21-22 °C (shielded from light)
- Differential loading: 0, 10, 100 and 1000 mg/L (at 1000 mg/L 3 replicates)
- Controls: no loading (4 replicates) and positive control 3,5 dichlorophenol ( 1 replicate at 3.2, 10 and 32 mg/L)
- Evidence of undissolved material: at 1000 mg/L visible dispersed test substance throughout and adhered to the side of flask
- pH adjustment: at 100 and 1000 mg/L

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source of inoculum/activated sludge: Severn Trent Water Plc sewage treatment plant Loughborough, Leicesterhire, UK
- Storage conditions: under aeration at 21 °C
- Storage length: used on the day of collection
- Preparation of inoculum for exposure: washed once by settlemnt and resuspended
- Concentration of sludge: suspended solids 3.0 g/L on day of the test
- pH: 7.2

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Post exposure observation period:

NA

Test temperature:

20-21 °C

pH:

at 30 min 7.6-7.8
at 3 hours 7.5-8.0

Dissolved oxygen:

measured at 30 minutes
in controls: 62-94% of saturation
in test solutions: 55-58% of saturation

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL
- Type: conical (open)
- Aeration: 0.1-0.5 L/min
- No. of vessels per concentration (replicates): 1 for 10 and 100 mg/L, 3 at 1000 mg/L
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Test water: deionized reverse osmosis water
- Concentration of sludge: suspended solids 3.0 g/L on day of the test
- pH: 7.6-7.8 (initial after adjustment)
- respiratory substrate (dissolved in 1 liter of water with the aid of ultrasonication):
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
- Adjustment of pH: yes at 100 and 1000 mg/L
- Test temperature: 20-21 ºC

EFFECT PARAMETERS MEASURED : oxygen consumption at t=30 min and t=3 h (over linear part of the respiration curve)

TEST CONCENTRATIONS: 10, 100 and 1000 mg/L

Reference substance (positive control):

yes

Remarks:

3,5 dichlorophenol

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

oxygen respiration rate controls: 26.65. mg O2/g dry weight sludge/h
coefficient of variation replicates at 1000 mg/L : 4.0%

Results with reference substance (positive control):

EC50 for 3,5 dichlorophenol 7.1 mg/L (oxygen concentration at initial reading at 10 and 32 mg/l was > 7.0 mg/L)

Reported statistics and error estimates:

Bartlett test for homogeneity of variance
Dunnett test for statistically differences between test groups and controls

Validity criteria fulfilled:

yes

Remarks:

it was concluded that the deviations of the oxigen concentrations did not affect the study outcome

Conclusions:

In a respiration inhibition test the NOEC of the test substance was 1000 mg/L

Executive summary:

The test substance was tested in a respiration inhibition test at concentrations of 10, 100 and 1000 mg/L. No effects on the respiratory rate of the inoculum were reported at any of the concentrations tested. The NOEC is therefore 1000 mg/L.

Description of key information

The EC50 and NOEC were determined to be above the nominal tested concentration of 1000 mg/L (Harlan 2015)

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L