Sodium permanganate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

See the read-across report attached in Section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

560 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-02-01

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

See the read-across report attached in Section 13.

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Post exposure observation period:

Not applicable i.e. not performed after 3hrs

Hardness:

140 mg/L as CaCO3

Test temperature:

21+/-1°C

pH:

7.2-7.9

Dissolved oxygen:

Initial reading = 4.7-7.0 mg/L
Final reading = 1.5- 3.7 mg/L

Salinity:

Not applicable as freshwater used.

Nominal and measured concentrations:

Nominal concentrations were 10, 32, 100, 320 and 1000 mg MnSO4/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 500mL conical flask
- Type : open
- Aeration: yes
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 3.8g/L in actual activated sewage sludge, of which 16 ml used in tests.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Alvaston water supply
- Total organic carbon: 1.018 mg/L average
- Metals: Aluminium < 15.57 µg/L average, iron < 11.4µg/L, mercury < 0.012µg/L, nickel < 3.04µg/L, lead < 2.3 µg/L, sodium 25µg/L, manganese < 1.5µg/L, Selenium < 0.5µg/L
- Pesticides: no single species was > 0.1 µg/L
- Chlorine: 0.307 mg/L
- Alkalinity: 7.62 average
- Conductivity: 386.192 µS/cm at 20°C


OTHER TEST CONDITIONS
- Light intensity: normal lighting

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : 0 hrs and after 30 min, and 3 hrs: Observation of test preparation. 3 hr: oxygen consumption rate

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
- Test concentrations: 10, 32, 100, 320, 1000 mg MnSO4/L

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

560 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no precipitation
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: Variation in respiration rates of controls 1 and 2 after 3 hours contact time was ± 3%.

Reported statistics and error estimates:

Not reported

Table 1 Oxygen Consumption Rates and Percentage Inhibition Values after 3 Hours Contact Time

Nominal Concentration (mg/l)		Initial O2 (mg O2/l)	Measurement Period (minutes)	Final O2Reading (mg O2/l)	O2Consumption Rates (mg O2/l/min)	% Inhibition
Control	R1	6.0	7	2.5	0.50	-
	R2	4.8	4	2.7	0.53	-
Test item	10	4.7	6	1.5	0.53	[3]
	32	4.8	5	2.0	0.56	[9]
	100	5.2	5	2.5	0.54	[5]
	320	5.3	6	2.2	0.52	[1]
	1000	7.0	10	3.7	0.33	36
3,5-dichlorophenol	3.2	5.9	10	1.6	0.43	17
	10	7.3	10	5.2	0.21	59
	32	8.0	10	7.2	0.08	84

[Increase in respiration rate as compared to controls]

R₁– R₂= Replicates 1 to 2

Table 2 pH Values of the Test Preparations at the Start and End of the Exposure Period

Nominal Concentration (mg/l)		pH
		0 Hours	3 Hours
Control	R1	7.5	7.9
	R2	7.7	7.9
Test item	10	7.6	7.8
	32	7.5	7.8
	100	7.5	7.7
	320	7.3	7.7
	1000	7.2	7.9
3,5-dichlorophenol	3.2	7.5	8.0
	10	7.5	8.1
	32	7.6	8.3

R₁– R₂= Replicates 1 to 2

Table 3 Observations on the Test Preparations Throughout the Test Period

Nominal Concentration (mg/l)		Observations on Test Preparations
		0 Hours	30 Minutes Contact Ti	3 Hours Contact Ti
Control	R1	Dark brown dispersion	Dark brown dispersion	Dark brown dispersion
	R2	Dark brown dispersion	Dark brown dispersion	Dark brown dispersion
Test item	10	Clear colourless solution[1]	Dark brown dispersion, no undissolved test item visible	Dark brown dispersion, no undissolved test item visible
	32	Clear colourless solution*	Dark brown dispersion, no undissolved test item visible	Dark brown dispersion, no undissolved test item visible
	100	Clear colourless solution*	Dark brown dispersion, no undissolved test item visible	Dark brown dispersion, no undissolved test item visible
	320	Clear colourless solution*	Dark brown dispersion, no undissolved test item visible	Dark brown dispersion, no undissolved test item visible
	1000	Clear colourless solution*	Dark brown dispersion, no undissolved test item visible	Dark brown dispersion, no undissolved test item visible
3,5-dichlorophenol	3.2	Dark brown dispersion, no undissolved reference item visible	Dark brown dispersion, no undissolved reference item visible	Dark brown dispersion, no undissolved reference item visible
	10	Dark brown dispersion, no undissolved reference item visible	Dark brown dispersion, no undissolved reference item visible	Dark brown dispersion, no undissolved reference item visible
	32	Dark brown dispersion, no undissolved reference item visible	Dark brown dispersion, no undissolved reference item visible	Dark brown dispersion, no undissolved reference item visible

R₁– R₂= Replicates 1 to 2

[1]Observations made prior to the addition of synthetic sewage and activated sewage sludge.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the study MnSO4 is not considered toxic to micro-organisms in the STP with an EC50 > 1000 mg/L and No Observable Effect Concentration (NOEC) = 560 mg/L. In terms of Mn2+ this equates to EC50 >325 mg Mn/L and NOEC = 182 mg Mn/L.

Executive summary:

The activated sludge respiration inhibition of the read across source substance was assessed according to OECD Test Guideline 209 and EU Method C.11 and in compliance with GLP.

Under the conditions of the study, the 3 h EC50 for the read across source substance was > 1 000 mg/L.  The NOEC was 500 mg/L.

Description of key information

Under the conditions of the study, the 3 h EC50 for the read across source substance was > 1 000 mg/L.  The NOEC was 500 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

500 mg/L

Additional information

The activated sludge respiration inhibition of the read across source substance was assessed according to OECD Test Guideline 209 and EU Method C.11 and in compliance with GLP. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

Under the conditions of the study, the 3 h EC50 for the read across source substance was > 1 000 mg/L.  The NOEC was 500 mg/L.