Toxicity to aquatic algae and cyanobacteria.003 to .004

Toxicity to aquatic algae and cyanobacteria.003

Administrative data

Purpose flag:

key study

Study result type:

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

Analysis of the test solution was performed, but it was not possible to differentiate from the background.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report Date:

1991

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

EPA OPP 122-2 (Algal Toxicity, Tiers I and II)

Deviations:

no

GLP compliance:

yes

Remarks:

no certificate joined

Test materials

Identity of test material same as for substance defined in section 1 (if not read-across):

no

Test material identityopen allclose all

Test material identity 1

Identifier:

CAS number

Identity:

7758-19-2

Test material identity 2

Identifier:

EC number

Identity:

231-836-6

Test material identity 3

Identifier:

IUPAC name

Identity:

sodium chlorite

Details on test material:

Lot/Batch number: 09-M, PAL M-033
Purity: 80 %

Analytical monitoring:

yes

Details on sampling:

Cell counts were made during the 96 h test. Temperature of the incubator was measured and recorded daily, and pH was detected in each test vessel at the beginning and end of the test.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 1.00 mg/L of stock solution was prepared by placing 0.0625 g of test substance in a class A volumetric flask and adjusting the mixture to 50 mL with test media.
- Eluate: sterile water enriched media, adjusted to pH= 7.5.
- Differential loading: no data
- Controls: no data
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): no data
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): no data
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no data

Test organisms

Test organisms (species):

Selenastrum capricornutum (new name: Pseudokirchnerella subcapitata)

Details on test organisms:

TEST ORGANISM
- Common name:Algae
- Strain: no data
- Source (laboratory, culture collection): Culture Collection of Algae, University of Texas at Austin
- Age of inoculum (at test initiation): no data
- Method of cultivation: no data

ACCLIMATION
- Acclimation period: no data
- Culturing media and conditions (same as test or not): no data
- Any deformed or abnormal cells observed: no data

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Post exposure observation period:

no data

Test conditions

Hardness:

no data

Test temperature:

24.5 - 25.3 °C

pH:

7.5 - 7.8

Dissolved oxygen:

no data

Salinity:

not applicable

Nominal and measured concentrations:

Nominal concentrations used in the preliminary test:
0.1, 1, 10, 100 and 1000 mg sodium chlorite/L
(Doses are equivalent to 0.075, 0.75, 7.5, 75 and 750 mg chlorite/L)

Nominal concentrations used in the actual test:
Nominal concentrations were 0 (control), 0.62, 1.25, 2.5, 5.0 and 10.0 mg/L.
(Doses are equivalent to 0, 0.46, 0.93, 1.87, 3.73 and 7.5 mg chlorite/L)

Details on test conditions:

TEST SYSTEM
- Test vessel: Class A volumetric flask
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 50 mL
- Aeration: no data
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): not applicable
- Initial cells density: 10 000 cells/mL
- Control end cells density: cells were counted daily during the 96 hours test.
- No. of organisms per vessel: no data
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates): not applicalbe

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: not applicable


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no data
- Photoperiod: 24:0
- Light intensity and quality: 35 µES-1/m²
- Salinity (for marine algae): not applicable

TEST CONCENTRATIONS
- Test concentrations: 0, 0.62, 1.25, 2.5, 5.0, and 10.0 mg/L

Reference substance (positive control):

no

Results and discussion

Effect concentrationsopen allclose all

Effect concentrations 1

Duration:

24 h

Endpoint:

EC50

Effect conc.:

8 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

24 h

Endpoint:

EC50

Effect conc.:

6 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

48 h

Endpoint:

EC50

Effect conc.:

6.4 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

48 h

Endpoint:

EC50

Effect conc.:

5 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Endpoint:

EC50

Effect conc.:

0.2 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Endpoint:

EC50

Effect conc.:

0.15 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 7

Duration:

96 h

Endpoint:

EC50

Effect conc.:

1 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks (e.g. 95% CL):

95% confidence interval of 0.62 t o1.25 mg/L

Effect concentrations 8

Duration:

96 h

Endpoint:

EC50

Effect conc.:

0.75 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Results of the preliminary test:
After 96 h the number of cells / mL was less than 50 % of the control value at 10, 00 and 1000 mg/L sodium chlorite and greater than 50 % at all other concentrations.

Results of the actual test:
Exposure of the algae to sodium chlorite for 96 h resulted in a median effective concentration (EC50) of 1.0 mg/L with a 95% confidence interval of 0.62 t o1.25 mg/L (equivalent to 6 mg chlorite/L). No effects were noted.

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

no data

Any other information on results incl. tables:

Table A7_4_1_3(2)-5:        Cell concentration data

		Number of cells/ml x 103
Nominal Concentration (mg sodium chlorite/L)	Replicate	0 h	24 h	48 h	72 h	96 h
0 (control)	1	10	42	100	346	1404
	2	10	54	108	428	1744
	3	10	46	132	446	1664
	mean	10	47	113	407	1604
	% control	100	100	100	100	100
0.62	1	10	44	104	358	1484
	2	10	56	132	436	1852
	3	10	40	110	412	1316
	mean	10	47	115	402	1551
	% control	100	100	102	99	97
1.25	1	10	42	92	156	274
	2	10	36	96	236	631
	3	10	34	110	190	576
	mean	10	37	99	194	494
	% control	100	79	88	48	31
2.5	1	10	40	108	228	364
	2	10	32	112	182	326
	3	10	34	92	176	296
	mean	10	35	104	195	329
	% control	100	74	92	48	20
5.0	1	10	44	90	108	138
	2	10	22	80	122	212
	3	10	32	54	60	116
	mean	10	33	75	97	155
	% control	100	70	66	24	10
10.0	1	10	16	30	12	16
	2	10	24	26	24	14
	3	10	18	16	18	12
	mean	10	19	24	18	14
	% control	100	40	21	4	1

Applicant's summary and conclusion

Conclusions:

Exposure of algae to sodium chlorite for 96 h resulted in a median EC50 of 1.0 mg/L, with a 95% confidence interval of 0.62 to 1.25 mg/L (equivalent to 0.75 mg chlorite/L)

Executive summary:

Freswater algae, Selenastrum capricornutum, was exposed to sodium chlorite in an acute toxicity test, to determine the EC50 (96h). The experiment was conducted during 96 hours, under GLP and following the US EPA-FIFRA Guideline 122 -2. The test was performed under static conditions with 5 concentrations of sodium chlorite: 0.62, 1.25, 2.5, 5.0, and 10.0 mg/L of sodium chlorite (nominal concentrations). Exposure experiment resulted in an EC50(96h) = 1.0 mg/L of sodium chlorite.

Validity criteria fulfilled:

no data

Toxicity to aquatic algae and cyanobacteria.004

Administrative data

Purpose flag:

weight of evidence

Study result type:

experimental result

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

Experiment following guideline, but not under GLP. Scientific results acceptable.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report Date:

2008

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

other guideline: EPA-600-R-95-136

GLP compliance:

no

Test materials

Identity of test material same as for substance defined in section 1 (if not read-across):

no

Test material identity

Identifier:

CAS number

Identity:

7758-19-2

Details on test material:

- Name of test material (as cited in study report): Sodium chlorite
- Molecular formula (if other than submission substance): no data
- Molecular weight (if other than submission substance): no data
- Smiles notation (if other than submission substance): no data
- InChl (if other than submission substance): no data
- Structural formula attached as image file (if other than submission substance): no data
- Substance type: solution
- Physical state: liquid
- Analytical purity: no data
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components: no data
- Isomers composition: no data
- Purity test date: no data
- Lot/batch No.: no data
- Expiration date of the lot/batch: no data
- Radiochemical purity (if radiolabelling): not applicable
- Specific activity (if radiolabelling): not applicable
- Locations of the label (if radiolabelling): not applicable
- Expiration date of radiochemical substance (if radiolabelling): not applicable
- Stability under test conditions: no data
- Storage condition of test material: no data
- Other: none

Details on properties of test surrogate or analogue material:

no data

Analytical monitoring:

no

Details on sampling:

no data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test concentrations for chlorite were prepared volumetrically from a 5000 mg/L stock solution of chlorite, which was prepared by addition of sodium chlorite to deionized water.
- Eluate: deionized water
- Differential loading: 0.5 X dilution series
- Controls: only seawater
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not applicable
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no data

Test organisms

Test organisms (species):

other: Macrocystis pyrifera

Details on test organisms:

TEST ORGANISM
- Common name: Macrocystis pyrifera
- Strain: no data
- Source: La Jolla Cove, San Diego
- Age at study initiation (mean and range, SD): Spores
- Length at study initiation (length definition, mean, range and SD): no data
- Weight at study initiation (mean and range, SD): no data
- Method of breeding: no data
- Feeding during test
- Food type: none
- Amount: no data
- Frequency: none

ACCLIMATION
- Acclimation period: no data
- Acclimation conditions (same as test or not): no data
- Type and amount of food: no data
- Feeding frequency: no data
- Health during acclimation (any mortality observed): no data

QUARANTINE (wild caught)
- Duration: no data
- Health/mortality: no data

Study design

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

no data

Test conditions

Hardness:

no data

Test temperature:

15+-1°C

pH:

no data

Dissolved oxygen:

no data

Salinity:

32+-2 ppt

Nominal and measured concentrations:

- nominal conc.: 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 mg/L
- measured conc.: -, -, -, -, 1.9, -, -, 15.4 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL Petri dish
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 30 mL
- Aeration: none
- Type of flow-through (e.g. peristaltic or proportional diluter): no data
- Renewal rate of test solution (frequency/flow rate): Daily solution renewal
- No. of organisms per vessel: not applicable
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 5
- No. of vessels per vehicle control (replicates): not applicable
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Seawater from Scripps Institute, San Diego
- Total organic carbon: no data
- Particulate matter: no data
- Metals: no data
- Pesticides: no data
- Chlorine: no data no data
- Alkalinity: no data
- Ca/mg ratio: no data
- Conductivity: no data
- Culture medium different from test medium: no data
- Intervals of water quality measurement: no data

OTHER TEST CONDITIONS
- Adjustment of pH: no data
- Photoperiod: 16:8
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Justification for using less concentrations than requested by guideline: not applicable
- Range finding study
- Test concentrations: 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 mg/L
- Results used to determine the conditions for the definitive study: no data

Reference substance (positive control):

yes

Remarks:

Copper chloride

Results and discussion

Effect concentrationsopen allclose all

Effect concentrations 1

Duration:

48 h

Endpoint:

EC50

Effect conc.:

> 15.4 mg/L

Basis for effect:

other: spore germination/tube length

Effect concentrations 2

Duration:

48 h

Endpoint:

NOEC

Effect conc.:

ca. 15.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: germination, germ tube length

Details on results:

no data

Results with reference substance (positive control):

- Results with reference substance valid
- EC50 Germination: 146 µg/L
- EC50 germ tube length: > 320 µg/L 
- Other: none

Reported statistics and error estimates:

Statistical analyses were calculated based on the measured value.

Any other information on results incl. tables:

Table: Results (means +- standard deviation) of the 48h toxicity test using M. pyrifera.

Chlorine dioxide (mg/L)			Survival (%)	Biomass (mg)
Nominal	Measured
0	-		82.8 ± 7.2	13.1 ± 0.7
0.25	-		85.8 ± 5.7	13.2 ± 0.7
0.5	-		86.4 ± 5.5	12.8 ± 0.6
1	-		80.6 ± 7.0	12.6 ± 0.5
2	1.9		83.4 ± 5.2	12.2 ± 1.2
4	-		83.2 ± 6.1	13.5 ± 0.5
8	-		83.2 ± 5.9	12.8 ± 0.7
16	15.4		85.4 ± 5.0	12.9 ± 0.8

Applicant's summary and conclusion

Conclusions:

Toxicity of the substance has been tested on M. pyrifera, in a 48h acute test. The results demonstrated a NOEC of 15.4 mg/L of chlorite for germination % and germ tube length; and an EC50(48h) > 15.4 mg/L of chlorite for germination and germ tube length..

Executive summary:

Toxicity of the substance has been tested on Macrocystis pyrifera, in a 48h acute static test, following US EPA Guideline EPA-600 -R-95 -136. A control and seven different concentrations (0.25, 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 mg/L) were tested in 4 replicates. The results demonstrated a NOEC of 15.4 mg/L of chlorite for germination and germ tube length; and an EC50(48h) > 15.4 mg/L of chlorite for germination and germ tube length.