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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
31.03.2006 - 27.04.2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study performed according to the guideline.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
Test substance concentrations measured in the test solution decreased by more than 20% during the test. This minor deviation did not affect the outcome of the study.
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
yes
Remarks:
Test substance concentrations measured in the test solution decreased by more than 20% during the test. This minor deviation did not affect the outcome of the study.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Appearance of Potassium permanganate - Dark violet, purple crystalling powder with bronze lustre.
Batch number – 69
Impurities - Manganese dioxide - cc 0.1%
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Potassium permanganate is being used as a surrogate for sodium permanganate. Read-across from potassium permanganate to sodium permanganate is appropriate from the ecotoxicological point of view as the most toxicologically relevant part of the substances is the same (permanganate). The contribution of the sodium/potassium ions to the toxicity of the respective substances is likely to be minimal. The toxicity of both substances is therefore likely to be very similar and will be dominated by local (site of contact) irritant/corrosive effects and systemic toxicity due to the absorption of manganese ions.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Concentrations of potassium permanganate were verified analytically by spectrophotometry at test initiation, after 24, 48 hours and termination. Samples were stored at room temperature prior to analysis.

Test solutions

Vehicle:
no
Details on test solutions:
The test material was soluble in algal growth medium in the range of concentration tested.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
The green freshwater algae Scenedesmus subspicatus Brinkmann 1953/SAG 86.84 obtained from the collection of autortrophic organisms of the Botani Institute of the Czech Academy of Science, Trebon on 27.03.2006.

The strain culture was preinoculated from the stock solution and cultivated in flasks with the test medium on indirect daylight at laboratory temperature. Algae inoculum for the test was sampled from exponentially growing inoculum culture. The strain culture was always set to pre-culturing cells for 3 dyas before the start of the test. Inoculum culture was kept 3 days under conditions at which the test was performed. After this period the culture was in the state of exponential growth and at a suitable cell density to perform the test. The cell density of the pre-culture was measured just before the start of the test and the required inoculum volume was calculated.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
Not applicable

Test conditions

Hardness:
Not applicable
Test temperature:
23 ± 2 deg C.
pH:
Measured range was 7.6 - 8.3.
Dissolved oxygen:
Not applicable
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal concentrations - 0 (control), 0.1, 0.15, 0.22, 0.32, 0.46, 0.68 and 1.0 mg/L. meaaured concentrations were found in the T0 samples, with theexception of the 0.22 mg/L treatment, the reason for this was not explained. After 24 hours measurable concentrations were only detected in the 1.0 mg/L treatment. After 48 and 72 hours no detectable levels of test material were found above the limit of quantification.
Details on test conditions:
The temperature was 23 ± 2 deg C over 72 hours in continous light (min 6000 lux, max. 10000 lux).
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
0.43 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: 0.30-0.56 mg/L
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
0.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 0.69-0.91 mg/L
Duration:
72 h
Dose descriptor:
other: NOECb
Effect conc.:
0.22 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
other: NOECr
Effect conc.:
0.32 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Results with reference substance (positive control):
The sensitivity of the algal culture is periodically verified by testing the reference substance, potassium dichromate. The results of the verification test carried out in March 2006 gave a 72h ErC50 of 0.98 mg/L (95% CI limits of 0.79 – 1.16 mg/L) and a 72h EbC50 of 0.44 mg/L (95% CI limits of 0.38 – 0.50 mg/L). This result is within the range for potassium dichromate provided by the Centre for Assessment of Laboratories of T.G. Masaryk Water Research Institute Prague in 2005 of between an EbC50 of between 0.34 and 0.89 mg/L and an ErC50 of between 0.66 and 1.84 mg/L.
Reported statistics and error estimates:
The ErC50 and EbC50 values were calculated by software 'Toxicity' (product of water research institute, Ostrava, Czech Republic). The determination of NOEC value was done by ANOVA analysis. The nominal concentration of the test substance was used for all evaluations and results.

Any other information on results incl. tables

Concentrations of the test substance at the beginning, after 24, 48 hours and at the end of the full test

Nominal Conc.

(mg/L)

Determined conc.

0 hours

[mg/L]

Determined conc.

24 hours

[mg/L]

Determined conc.

48 hours

[mg/L]

Determined conc.

72 hours

[mg/L]

1

0.6661

0.1566

< LOQ (< LOD)

< LOQ (< LOD)

0.68

0.3861

< LOQ (0.023)

< LOQ (< LOD)

< LOQ (< LOD)

0.46

0.1956

< LOQ (<LOD)

< LOQ (< LOD)

< LOQ (< LOD)

0.32

0.0980

< LOQ (<LOD)

< LOQ (< LOD)

< LOQ (< LOD)

0.22

< LOQ (< LOD)

< LOQ (<LOD)

< LOQ (< LOD)

< LOQ (< LOD)

0.15

0.0819

< LOQ (<LOD)

< LOQ (< LOD)

< LOQ (< LOD)

0.1

0.0578

< LOQ (<LOD)

< LOQ (< LOD)

< LOQ (< LOD)

LOD = Limit of detection (0.015 mg/L), LOQ = Limit of quantification (0.050 mg/L)

Mean cell density over the 72 hour exposure period

Nominal concentration (mg/L)

Mean cell density (cells/mL)

0 hours

24 hours

48 hours

72 hours

1.0

10000

18750

14583

14583

0.68

10000

45833

91666

322917

0.46

10000

70833

147917

531520

0.32

10000

70833

258333

804167

0.22

10000

91666

393750

1143750

0.15

10000

85417

422917

1327083

0.1

10000

95833

385417

1335417

Control

10000

106250

408333

1352083

Percentage reduction of growth rate and percentage inhibition of cell growth - full test

Nominal Conc.

(mg/L)

Growth rate

Cell growth

Mean growth (µ)

Reduction (%)

Mean area (A)

Inhibition (%)

1.0

0.13

92.3

15625

98.7

0.68

1.16

29.2

273958

76.5

0.46

1.32

19.0

459375

60.6

0.32

1.46

10.6

706250

39.4

0.22

1.58

3.4

1032292

11.4

0.15

1.63

0.4

1146875

1.6

0.1

1.63

0.3

1123958

3.6

Control

1.64

-

1165625

-

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
A 72 hour acute growth inhibition study with Scenedesmus subspicatus was performed to assess the toxicity of potassium permanganate. The study was performed according to GLP and the OECD 201 Test Guideline. The 72hour EbC50 was calculated to be 0.43 mg/L, with 95% confidence limits of 0.30 to 0.56 mg/L (based nominal exposure concentrations), the corresponding NOEC was 0.22 mg/L. The 72hour ErC50 was calculated to be 0.80 mg/L, with 95% confidence limits of 0.69 to 0.91 mg/L (based nominal exposure concentrations), the corresponding NOEC was 0.32 mg/L.
Executive summary:

A 72 hour acute growth inhibition study withScenedesmus subspicatuswas performed to assess the toxicity of potassium permanganate. The study was performed according to GLP and the OECD 201 Test Guideline. The 72hour EbC50 was calculated to be 0.43 mg/L, with 95% confidence limits of 0.30 to 0.56 mg/L (based nominal exposure concentrations), the corresponding NOEC was 0.22 mg/L.  The 72hour ErC50 was calculated to be 0.80 mg/L, with 95% confidence limits of 0.69 to 0.91 mg/L (based nominal exposure concentrations), the corresponding NOEC was 0.32 mg/L.