Methylamine

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: 1. Guideline study with acceptable restricitons 2. Test item concentration not verified 3. Non GLP-study

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Principles of method if other than guideline:

- Test for inhibition of the oxygen consumption by activated sludge
- Test mixtures (total volume: 250 mL) containing synthetic medium, inoculum (activated sludge) and four concentrations of the test item were incubated for 30 min at ambient temperature (20-25 °C)
- Afterwards, the respiration rate was measured.

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

The nominal concentrations ( 0, 158.4 mg/L, 264.4 mg/L, 500 mg/L, and 1000 mg/L) were not analytically verified. However, due to the low n-octanol/water partition coefficient (log Kow = -0.713), the high water solubility (completely miscible in water) and the low Henry´s law constant (HLC, uncharged: 1.58E-01 Pa*m³/mol) of the chemical and despite the high vapour pressure (VP = 3140 hPa at 20 °C); the concentrations are assumed to be stable.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Innoculum: activated sludge from a domestic wastewater plant treating municipal sewage

Test type:

other: aquatic

Nominal and measured concentrations:

- Concentrations of test chemical: 1000, 500, 264.4 and 158.4 mg/L

Details on test conditions:

- Concentration of dry substance in the test vessels 1 g/L
- The volatile test substance was directly added to the test vessels
- Temperature of incubation: 20 - 25 °C
- Appropriate controls and blank system used: yes [blank control (BC)]
- No reference substance used

Reference substance (positive control):

no

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

240 mg/L

Concentration [mg/L]	Respiration Rate	Blank [mgO2/L*h]	Compared to Control (%)
158.9	15	15	0
264.4	11	15	-27
500	14	19	-26
1000	11	19	-42

Validity criteria fulfilled:

yes

Conclusions:

EC20 (30min) = 240 mg/L (BASF AG, 1990).

Executive summary:

Activated sludge from a domestic wastewater treatment plant (treating municipal sewage) was used as inoculum at a temperature range of 20 - 25 °C to test the toxicity of monomethylamine to microorganisms. The experiment was performed by BASF AG in 1990, according to ISO 8192. Monomethylamine was tested in the concentrations of 158.4 mg/L, 264.4 mg/L, 500 mg/L, and 1000 mg/L. The result is an EC20 value of 240 mg/L during a total exposure time of 30 minutes.

Additional information

Activated sludge from a domestic wastewater treatment plant (treating municipal sewage) was used as inoculum at a temperature range of 20 - 25 °C to test the toxicity of monomethylamine to microorganisms. The experiment was performed by BASF AG in 1990, according to ISO 8192. Monomethylamine was tested in the concentrations of 158.4 mg/L, 264.4 mg/L, 500 mg/L, and 1000 mg/L. The result is an EC20 value of 240 mg/L during a total exposure time of 30 minutes.

The same experimental conditions to test the inhibition of the oxygen consumption by activated sludge were conducted by BASF AG in 1990. The only difference was the initial test concentrations of monomethylamine: 125, 250, 500, and 1007 mg/L. In this case, an EC20 value greater than the highest tested concentration (1007 mg/L) is given as result.