Sodium permanganate

Toxicity to aquatic plants other than algae

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

See the read-across report attached in Section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

30.72 other: mg Mn/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: Dissolved

Basis for effect:

other: Number of fronds, total dry weight and growth rate

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

64.94 other: mg Mn/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: Dissolved

Basis for effect:

other: Number of fronds, total dry weight and growth rate

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

23.37 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: Dissolved

Basis for effect:

frond number

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

26.44 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: Dissolved

Basis for effect:

other: Total dry weight

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

41.54 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: Dissolved

Basis for effect:

growth rate

Reference 2

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29/02/08- 09/07/08

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 221 (Lemna sp. Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

U.S. EPA GLP standard (40 CFR 792)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Total recoverable and dissolved (filtered through a 0.45 µm nylon mesh) manganese were detmined at test initiation and termination. Also dissolved Manganese was monitored on days 3 and 5.
- Sampling method: Media samples from each treatment were collected for determination of manganese at test initiation. Samples for dissolved manganese concentration were collected from the new renewal waters within each treatment on days 3 and 5. At test termination, samples were taken from replicate A for each concentration. Metal samples (~ 20 mLs) were taken from the centre of the test using a 30-mL syringe.
- Sample storage conditions before analysis:Samples were preserved with nitric acid (trace metal grade) to pH <2 prior to analysis

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was added to laboratory blended water to make a stock solution of 50 g Mn/L. The concentrations were prepared by adding the appropriate volume of stock solution to the growth media.
- Controls: dilution water.

Test organisms (species):

Lemna minor

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): Obtained from the University of Toronto culture and collection (UTCC; Toronto, ON, Canada). This strain was collected by Barabara E. Giles in 1977 from Wainfleet, Stinking Barn, Niagara Peninsula, Ontario, Canada.
- Age of inoculum (at test initiation): 9 Days old

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

7 d

Post exposure observation period:

Not reported

Hardness:

52 mg/L as CaCO3

Test temperature:

24±2°C

pH:

6.8-7.6

Dissolved oxygen:

Not reported

Salinity:

Not applicable

Nominal and measured concentrations:

3.88, 7.75, 15.5, 31 and 62 mg Mn/ L - Nominal concentration
<0.05, 3.35, 7.01, 15.57, 30.72 and 64.94 mg Mn/ L - Average measured dissolved concentration

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL beakers
- Type (delete if not applicable): open
- Fill volume: Holds approximately 200 mL of test solution
- No. of colonies per vessel: 9- 12 fronds
- No. of fronds per colony: 2- 4 visible fronds
- No. of vessels per concentration (replicates):3
- No. of vessels per control (replicates):3

GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:Test was conducted in a synthetic freshwater reconstituted from deionised water with the addition of appropriate reagent grade salts.
- Total organic carbon: 0.7 mg/ L (DOC = dissolved organic carbon. Measured via combustion (EPA 415.1; CH2M HILL, Corvallis, OR)
- Chlorine:20.5 mg/L (Measured via Ion Chromatography (EPA 300.0; CH2M HILL, Corvallis, OR)
- Alkalinity: 12 mg/L as CaCO3
- Conductivity:270 µS/ cm
- Intervals of water quality measurement: Hardness, alkalinity, total residual chlorine, and ammonia were measured in the dilution water at test initiation only. Temperature within the environmental chamber were recorded daily. Test solution pH was measured at test initiation on renewal days ( days 3 and 5) in both new and old waters.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod:Continous
- Light intensity and quality: 600 -930 foot candles.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of frond number: manual counting, computerized image analysis and examined for grossly observable abnormalities.
- Determination of biomass: dry weight. The colonies from each replicate were placed into a pre- weighed pan and dried at 60°C for 72 hours and then re-weighed to the nearest 0.01 mg to obtain a dry weight.
- Other: Normal and abnormal appearing fronds were determined at the beginning of the test, and on at least two occasions during the test. Changes in plant development (e.g. frond size, appearance, indication of necrosis, chlorosis or gibbosity, colony break-up or loss of buoyancy), and in root length and appearance was recorded.

RANGE-FINDING STUDY
- Test concentrations: 31 mg Mn/L and higher
- Results used to determine the conditions for the definitive study: The test concentrations were selected based on findings from a range-finder test that resulted in effects on growth at treatments at 31 mg Mn/L and higher.

Reference substance (positive control):

no

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

30.72 other: mg Mn/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: Number of fronds, total dry weight and growth rate

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

64.94 other: mg Mn/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: Number of fronds, total dry weight, and growth rate

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

23.37 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

frond number

Remarks on result:

other: 95% CL

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

26.44 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: Total dry weight

Remarks on result:

other: 95% CL

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

41.54 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: 95% CL

Details on results:

Not reported

Results with reference substance (positive control):

Not reported

Reported statistics and error estimates:

All statistical analyses were performed using the measured average dissolved manganese concentrations. Difference in growth (based on frond count, dry weight, biomass and growth rate) were evaluted using statistical computer packages (TRAP, U.S. EPA Duluth, MN, USA, and CETIS, Tidepool Scientific Software Mckinleyville, CA, USA). Since the data met the assumptions of normality and homogeneity, the NOEC and LOEC were estimated using an analysis of variance (Dunnett's) to compare (p=0.05) organism performance in the experimental treatments with the observed in the control. The EC10 was estimated using a piecewise linear regression. Exposure concentrations were log-transformed before determination of EC10 values.

 Table 5. Frond Count Data

 

Average Measured Dissolved Concentration.(mg Mn /L)	Total Number of Fronds (% abnormal)				Sig. Less than the Control^1
	Rep A	Rep B	Rep C	Average(±SD)
< 0.05	257	290	253	267±20	-
3.34	226	288	304	273±41	No
7.01	182(1)	250(0.4)	248(0.4)	227±39	No
15.57	273(3)	252	254(3)	260±12	No
30.72	233(8)	217	290(14)	247±38	No
64.94	172(49)	146	181(49)	166±18	Yes

¹Significantly less than the control (p =0.05) using Dunnett’s Test.

SD = Standard Deviation

 

Table 6. Total Dry weight

 

Average Measured Dissolved Concentration.(mg Mn /L)	Dry weights (units)				Sig. Less than the Control^1
	Rep A	Rep B	Rep C	Average(±SD)
< 0.05	24.82	29.56	23.80	26.06±3.07	-
3.34	24.57	31.82	33.18	29.86±4.63	No
7.01	20.25	25.91	24.40	23.52±2.93	No
15.57	30.75	26.12	25.37	27.41±2.91	No
30.72	23.60	19.33	22.83	21.92±2.28	No
64.94	11.12	10.46	12.46	11.35±1.02	Yes

¹Significantly less than the control (p =0.05) using Dunnett’s Test.

SD = Standard Deviation

 

Table 7.Growth Rate from Day 0 to Day 7

 

Average Measured Dissolved Concentration.(mg Mn /L)	Dry weights (units)				Sig. Less than the Control^1
	Rep A	Rep B	Rep C	Average(±SD)
< 0.05	5.24	5.36	5.22	5.27±0.08	-
3.34	5.11	5.35	5.40	5.29±0.16	No
7.01	4.88	5.20	5.20	5.09±0.19	No
15.57	5.27	5.20	5.20	5.22±0.04	No
30.72	5.05	4.99	5.20	5.08±0.11	No
64.94	4.15	4.00	4.22	4.13±0.11	Yes

  

Table 8.Summary of Test Statistics (mg Mn/ L)¹

Evaluation	Frond Count	Total Dry Weight	Growth Rate
NOEC	30.72	30.72	30.72
LOEC	64.94	64.94	64.94
EC10 (95 % CI)	23.37 (11.67-46.78)	26.44 (18.04- 38.74)	41.54 (37.37- 46.17)
EC20 (95% CI)	35.07 (21.22-57.94)	31.94 (23.59-43.26)	62.48 (54.96-71.04)

 ¹NOEC = No observed effect concentration. LOEC = Lowest observed effect concentration. EC10= 10% Effect concentration. EC50 = Median effect concentration. CI= Confidence intervals.

Validity criteria fulfilled:

yes

Remarks:

The doubling time of frond number in the control was less than 2.5 days (60h).

Conclusions:

Under the conditions of the study, the 7 day NOEC for the read across source substance was 30.72 mg Mn/L.

Executive summary:

The toxicity of the read across source substance to aquatic plants was assessed according to OECD Test Guideline 221 and in compliance with GLP.

Under the conditions of the study, the 7 day NOEC for the read across source substance was 30.72 mg Mn/L.

Description of key information

Under the conditions of the study, the 7 day NOEC for the read across source substance was 30.72 mg Mn/L.

Key value for chemical safety assessment

EC10 or NOEC for freshwater plants:

30.72 mg/L

Additional information

The toxicity of the read across source substance to aquatic plants was assessed according to OECD Test Guideline 221 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 7 day NOEC for the read across source substance was 30.72 mg Mn/L.