Calcium glycinate (1:2)

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:

2020

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes (incl. QA statement)

Test organisms (species):

activated sludge of a predominantly domestic sewage

Total exposure duration:

3 h

Remarks on exposure duration:

contact time 3 hours, during which aeration takes place

Test temperature:

20 ± 2°C

Details on test conditions:

Duration: contact time 3 hours, during which aeration takes place
Air supply: clean, oil-free air. Air flow 0.5 to 1 litre/minute
Nutrient solution: synthetic sewage feed
Test item concentrations:: 0.10, 1.0, 10.0, 100.0 and 1000.0 mg/l
Reference item concentrations: 0.01 , 0.1, 1.0 , 10.0 and 100.0 mg/l
Blank controls: Inoculated sample without test substance
Temperature: 20 ± 2°C
Test item stock solutions 10 g/l (at pH = 7.0) (no undissolved particles were
observed)
Reference substance stock solutions 1 g/l
Synthetic medium stock solution: See p. 3.1.4
Activated sludge stock suspension: 3 g/l of suspended solids
Activated sludge suspension in test vessels 1.5 g/l of suspended solids
ATU stock solution 2.32 g/l
*According to the OECD 209 GUIDELINES FOR THE TESTING OF CHEMICALS, Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation):
45. To avoid time-consuming and expensive analytics, it is recommended to simply weigh the test material directly into the test vessels and to refer to the initial weighed nominal concentration for subsequent calculations. A differentiation between dissolved, undissolved or adsorbed fractions of the test material is not necessary because all these fractions appear under real conditions in a waste water treatment plant likewise, and these fractions may vary depending on the composition of the sewage. The aim of the guideline is to estimate a non inhibitory concentration realistically and it is not suitable to investigate in detail which fractions make a contribution to the inhibition of the activated sludge organisms.
The initial nominal concentration were taken for subsequent calculations.

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

684.2 mg/L

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

909.1 mg/L

Basis for effect:

inhibition of heterotrophic respiration

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

532.3 mg/L

Basis for effect:

inhibition of nitrification rate

Duration:

3 h

Dose descriptor:

EC50

Remarks:

extrapolated

Effect conc.:

>= 1 000 mg/L

Basis for effect:

inhibition of nitrification rate

Details on results:

The lowest tested concentration that causes the observed respiration inhibition is equal to 0.1 mg/l.

Validity criteria fulfilled:

yes

Conclusions:

calculated values of the end points EC10 for the test item were found to be:
1. Total respiration inhibition: 684,2 mg/l.
2. Heterotrophic respiration inhibition: 909.1 mg/l.
3. Nitrification inhibition: 532,3 mg/l .

The lowest tested concentration that causes the observed respiration inhibition is equal to 0.1 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

EC10 or NOEC for microorganisms:

909.1 mg/L

Additional information

calculated values of the end points EC10 for the test item were found to be:
1. Total respiration inhibition: 684,2 mg/l.
2. Heterotrophic respiration inhibition: 909.1 mg/l.
3. Nitrification inhibition: 532,3 mg/l .