Manganese, [[2,2',2''-[nitrilotris[2,1-ethanediyl(nitrilo-.kappa.N)methylidyne]]tris[phenolato-.kappa.O]](3-)]-, (OC-6-22)-

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2002-11-08 o 2003-01-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline study, GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

adopted 1993

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

479-540-8

EC Name:

-

Cas Number:

61007-89-4

Molecular formula:

C27 H27 Mn N4 O3

IUPAC Name:

manganese(3+) 2-[({2-[bis(2-{[(2-oxidophenyl)methylidene]amino}ethyl)amino]ethyl}imino)methyl]benzen-1-olate

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Source: Activated sludge of a communal sewage treatment plant (ARA Therwil)
- Preparation of inoculum for exposure: The inoculum was prepared the day before experimental start. The freshly collected activated sludge was washed 3 times with tap water. Subsequently the sludge was aerated. The day the test started, a sample of the activated sludge was taken to determine the dry weight ofthe suspended solids. The pH ofthe inoculum was 7.5.
- Initial biomass concentration: 3.75 g/L suspended solids

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

20 °C

pH:

7.7

Nominal and measured concentrations:

Nominal: 11, 19, 33, 57, and 100 mg/L.

Details on test conditions:

TEST SYSTEM
- Aeration: 0.1 - 0.2 L/min/100 mL by Pasteurpipette
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Sludge dry weight: 1.5 g/L suspended solids

TEST MEDIUM / WATER PARAMETERS
- Synthetic sewage feed: in accordance to the guideline

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: no

EFFECT PARAMETERS MEASURED
O2 consumption: measured with an oxygen sensitive electrode system: OXI 530
pH: measured at the end of the test

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol (3.2, 10, and 32 mg/L)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

At all applied test concentrations, the test item showed no significant toxic effects (inhibition of the respiration rate < 15%) to the activated sludge.

Results with reference substance (positive control):

The 3-hour EC50 of the reference item 3,5-dichlorophenol (positive control) was calculated to be 9 mg/L.