Toxicity to other aquatic organisms.001 to 005

Toxicity to other aquatic organisms.001

Administrative data

Purpose flag:

weight of evidence

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report Date:

2006

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

other guideline: E1218-97a (ASTM 1998)

GLP compliance:

no

Test materials

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

yes

Test material identity

Identifier:

CAS number

Identity:

10049-04-4

Details on test material:

- Name of test material (as cited in study report): Chlorine dioxide
- 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: powder
- Physical state: solid dissolved in deionized water
- 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:

- Concentrations: 0, 0.26, 0.52, 1.04, 2.09, 4.18 mg/L
- Sampling method: test concentrations were verified at the beginning of the test using HACH DPD Method 10126
- Sample storage conditions before analysis: no data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution was made from powered product supplied by Ecochlor. Two separate powders were mixed according to directions by dissolving them in deionized water and bringing the volume to one liter to obtain a target concentration of 3000 ppm chlorine dioxide.
- 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: Skeletonema costatum

Details on test organisms:

TEST ORGANISM
- Common name: Skeletonema costatum
- Strain: no data
- Source: In house culture, culture obtained from UTEX (Austin, TX)
- Age at study initiation (mean and range, SD): Log phase growth, 6 day old culture
- 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: no data
- Amount: no data
- Frequency: no data

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:

96 h

Post exposure observation period:

no data

Test conditions

Hardness:

no data

Test temperature:

20+-2°C

pH:

no data

Dissolved oxygen:

no data

Salinity:

32+-2 ppt

Nominal and measured concentrations:

- nominal conc.: 0, 0.26, 0.52, 1.04, 2.09, 4.18 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 125 mL Petri dish
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 50 mL
- Aeration: none
- Type of flow-through (e.g. peristaltic or proportional diluter): no data
- Renewal rate of test solution (frequency/flow rate): no data
- No. of organisms per vessel: not applicable
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- 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, La Jolla
- 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, 0.26, 0.52, 1.04, 2.09, 4.18 mg/L
- Results used to determine the conditions for the definitive study: no data

Reference substance (positive control):

no

Results and discussion

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 S. costatum.

Chlorine dioxide (mg/L)	Cell density (x10e4)
0	52.5 ± 1.4
0.26	54.7 ± 2.4
0.52	53.4 ± 2.4
1.04	51.4 ± 3.0
2.09	51.7 ± 1.5
4.18	0

Applicant's summary and conclusion

Conclusions:

Toxicity of the substance has been tested on S. costatum, in a 96h acute static test. The results demonstrated a NOEC of 2.09 mg/L of chlorine dioxide for cell density criterion; an IC50(96h) = 3.09 mg/L.

Executive summary:

Toxicity of the substance has been tested on Skeletonema costratum, in a 96h acute-static test, following ASTM Guideline E1218 -97a. A control and five different concentrations (0.26, 0.52, 1.04, 2.09, 4.18 mg/L) were tested in 4 replicates. The results demonstrated a NOEC of 2.09 mg/L of chlorine dioxide for cell density criterion; an IC50(96h) = 3.09 mg/L.

Validity criteria fulfilled:

no data

Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.

Toxicity to other aquatic organisms.002

Administrative data

Purpose flag:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

Guideline followed 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 data

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:

No data

Details on properties of test surrogate or analogue material:

No data

Analytical monitoring:

no data

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: Strongylocentrotus purpuratus

Details on test organisms:

TEST ORGANISM
- Common name: Strongylocentrotus purpuratus
- Strain: no data
- Source: Mission Bay, San Diego
- Age at study initiation (mean and range, SD): Gametes
- 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:

96 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, 1.0, 2.0, 4.0, 8.0, 16.0 mg/L
- measured conc.: -, -, -, -, -, 19.8 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass vial
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 10 mL
- Aeration: none
- Type of flow-through (e.g. peristaltic or proportional diluter): no data
- Renewal rate of test solution (frequency/flow rate): none
- 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, 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:

96 h

Endpoint:

EC50

Effect conc.:

ca. 10.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: development

Effect concentrations 2

Duration:

96 h

Endpoint:

NOEC

Effect conc.:

ca. 5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: development

Details on results:

no data

Results with reference substance (positive control):

- Results with reference substance valid
- EC50 normality: 21.3 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 96h toxicity test using S. purpuratus.

Chlorine dioxide (mg/L)			Development (%)
Nominal	Measured
0	-		89.0 ± 6.6
1	-		91.4 ± 2.6
2	-		92.6 ± 3.8
4	-		87.8 ± 7.5
8	-		54.6 ± 18.1
16	19.8		0

Applicant's summary and conclusion

Conclusions:

Toxicity of the substance has been tested on S. purpuratus, in a 96h acute static test. The results demonstrated a NOEC of 5.0 mg/L of chlorite for development; an EC50(96h) = 10.4 mg/L.

Executive summary:

Toxicity of the substance has been tested on Strongylocentrotus purpuratus, in a 96h acute-static test, following US EPA Guideline EPA-600 -R-95 -136. A control and five different concentrations (1.0, 2.0, 4.0, 8.0, and 16.0 mg/L) were tested in 5 replicates. The results demonstrated a NOEC of 5.0 mg/L of chlorite for development; an EC50(96h) = 10.4 mg/L.

Validity criteria fulfilled:

no

Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.

Toxicity to other aquatic organisms.003

Administrative data

Purpose flag:

supporting study

Study result type:

experimental result

Reliability:

4 (not assignable)

Data source

Reference

Reference Type:

publication

Title:

Toxicity of chlorine dioxide to early life stages of marine organisms.

Author:

Hose JE, Di Fiore D, Parker HS and Sciarrotta T

Year:

1989

Bibliographic source:

Bull Environ Contam Toxicol, 42: 315-319

Materials and methods

GLP compliance:

no data

Test materials

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

yes

Test material identityopen allclose all

Test material identity 1

Identifier:

CAS number

Identity:

10049-04-4

Test material identity 2

Identifier:

EC number

Identity:

233-162-8

Test organisms

Test organisms (species):

other: Strongylocentrotus purpuratus

Test conditions

Test temperature:

(Monitored at the termination of the bioassay) Within the required limits of APHA (1980).

pH:

(Monitored at the termination of the bioassay) Within the required limits of APHA (1980).

Dissolved oxygen:

(Monitored at the termination of the bioassay) Within the required limits of APHA (1980).

Salinity:

(Monitored at the termination of the bioassay) Within the required limits of APHA (1980): 33 ppt.

Results and discussion

Any other information on results incl. tables:

Table: Effects of chlorine dioxide on early life stages of the sea bass (Paralax clanthratus). Concentrations which are significantly different from the control are starred.

Organism	Endpoint	Dose (mg/L)	Response (x + SD (n))
Purple sea urchin	% abnormal	0.0000	9.3 ± 3.4 (5)
		0.0025	10.5 ± 3.6 (5)
		0.0250	9.3 ± 2.1 (5)
		0.250	15.1 ± 4.4 (5)
		2.50	10.7 ± 3.5 (5)
		25.0	12.0 ± 2.3 (5)
		250.0	15.1 ± 2.1 (5) *

Applicant's summary and conclusion

Toxicity to other aquatic organisms.004

Administrative data

Purpose flag:

supporting study

Study result type:

experimental result

Study period:

31 May 2010 until 4 June 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

well conducted study according to standard protocol with chemical analyses and GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report Date:

2010

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

other guideline: ISO/DC 20666

Deviations:

yes

Remarks:

test duration is 96h and performed in continuous light

Principles of method if other than guideline:

The toxicity test was conducted with 8 wells with 1 animal in each for each test concentration, 16 control wells were used for control. The test animals were less than 24 hours old. Newly hatched rotifers were selected based on shape and size. A 24 Multiwell plate was used for incubation. A concentrated culture of Nannochloropsis oceanica and Tetraselmis suecica were added to each well at the start to give an algal cell concentration of >3x10E6 cells/ml.

GLP compliance:

yes

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:

7775-09-9

Details on test material:

Reach sample: 0043
Batch number: 20001809
Expiry date: 7/3/2010
Appearance: White powder
Purity: 99.7 ± 0.6%
Date received: 27 April 2010
Storage conditions: In darkness at room temperature
Expiry date: 3 July 2010

Analytical monitoring:

yes

Details on sampling:

Sodium Chlorate levels were analysed in the test solution before addition of test organisms and feed algae suspension and at the end of the test.

Vehicle:

no

Details on test solutions:

The test concentrations were prepared by diluting a stock solution of 1000 mg/l of Sodium Chlorate with appropriate amount of aged sea water.

Test organisms

Test organisms (species):

other: brachionus plicatilis

Details on test organisms:

Source: SINTEF, Norway
Stock culture: Cultured in natural seawater fed with Nannochloropsis oceanica weekly batches, temperature 20 oC and 25 PSU
Lifestage/Age: Newly hatched rotifers, less than 24 h old

Study design

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Test temperature:

20.1 - 20.5 °C

pH:

7.89 - 8.16

Dissolved oxygen:

> 7.7 mg/L

Nominal and measured concentrations:

Sample nominal Measured Sodium Chlorate % of nominal
10 mg/l initial 8.2 82
10 mg/l end 6.6 66
22 mg/l initial 19.3 88
22 mg/l end 16.8 76
46 mg/l initial 42 92
46 mg/l end 35 77
100 mg/l initial 99 99
100 mg/l end 92 92
220 mg/l initial 218 99
220 mg/l end 185 84
460 mg/l initial 471 102
460 mg/l end 392 85
1000 mg/l initial 1031 103
1000 mg/l end 865 86

Details on test conditions:

TEST SYSTEM
- Test vessel: 24 Multiwell plate
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 8
- No. of vessels per control (replicates): 16

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Aged sea water was used as control medium and for dilution of Sodium Chlorate. The sea water was sieved (1 μm) in order to exclude particles and other organisms.
- Culture medium different from test medium: No

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: continuous light
- Light intensity: not known

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : number of offspring using a low power stereoscopic microscope, mortality

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all

Effect concentrations 1

Effect concentrations 2

Effect concentrations 3

Details on results:

Chemical analysis
Initial test concentrations are measured to be between 82 and 103 % of nominal. After test end the test solutions were collected and filtered before chemical analysis. Test concentrations were then measured to be between 66 and 92 % of nominal. Most test concentrations showed a decrease of approximately 15 % from start to end. 
Almost all mean concentrations were > 80% of the nominals. Only the lowest test concentration was below 80% (74%), but this is not a critical concentration, therefore nominals were used for effect calculations.

Results with reference substance (positive control):

EC50 = 5.6 mg/L for growth inhibition.

Reported statistics and error estimates:

NOEC was determined using the Dunnett’s test with JMP statistical package of SAS institute (1989-1997). EC10 and EC50 values were determined using logistic regression analysis.

Any other information on results incl. tables:

Number of offspring after 96 hours exposure to Sodium Chlorate.

Replicate no	Control	1000 mg/L	460 mg/L	220 mg/L	100 mg/L	46 mg/L	22 mg/L	10 mg/L
1	7	4	3	5	4	7	6	7
2	7	2	3	5	3	7	7	7
3	6	2	3	3	4	6	8	8
4	6	3	4	5	7	5	7	7
5	7	5	6	3	6	5	6	7
6	6	2	5	4	3	5	6	8
7	6	2	4	3	5	6	7	8
8	6	2	7	5	4	4	4	6
9	7
10	6
11	8
12	8
13	7
14	7
15	9
16	8
Total	111	22	35	33	36	45	51	58
Average	6.9	2.8	4.4	4.1	4.5	5.6	6.4	7.3
% inhib	0.0	60.4	36.9	40.5	35.1	18.9	8.1	-4.5

Applicant's summary and conclusion

Conclusions:

The test was well conducted according to standard protocol with chemical analysis and GLP.
Sodium chlorate is not very toxic to the marine rotifer Brachionus plicatilis.

Executive summary:

The effect of Sodium Chlorate on the reproduction to the marine rotatoria Brachionus plicatilis has been investigated. The test was performed according to ISO/DC 20666- Water quality – Determination of the chronic toxicity to Brachionus calcyflorus in 48h. The test concentrations were 10, 22, 46, 100, 220, 460 and 1000 mg/l of Sodium Chlorate. Aged seawater was used as control in the test.

The test was performed with 8 replicate vessels with 1 animal in each, for each test concentration and 16 control replicate vessels. The vessels were incubated for 96 hours at 20 ±1 °C. Mortality and number of offspring were recorded after 96 hours.

There was a dose dependent reduction in reproduction observed for B. plicatilis, when exposed to Sodium Chlorate. Statistical assessment indicate a NOEC of 46 mg/l Sodium Chlorate. EC50 was estimated to be 596 mg/l Sodium Chlorate. Mortality of parent rotatoria was not observed at any concentration.

The test indicates that high concentration of Sodium Chlorate exerts a reproductive inhibition on B. plicatilis.

Validity criteria fulfilled:

yes

Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.

Toxicity to other aquatic organisms.005

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:

GLP study according to protocol. No chemical analyses were performed on the test concentration only the stock solution were analyzed. From results in chronic tests it can be assumed that the test concentrations were stable and that the organisms were exposed.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report Date:

1991

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

other guideline: U.S. EPA-FIFRA, Guideline 72-3

GLP compliance:

yes

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:

7775-09-9

Test material identity 2

Identifier:

EC number

Identity:

231-887-4

Test material identity 3

Identifier:

IUPAC name

Identity:

sodium chlorate

Details on test material:

- Purity: > 99%
- Lot no.: 29-A, PAL A-133

Analytical monitoring:

yes

Details on sampling:

The concentration of sodium chlorate test media could not be determined because of naturally occurring interferences in the dilution water. The available analytical methods were effective in deionized water used to prepare toxicant stock solution but not in the dilution water. Approximately 5 ml of the 500,000 mg/L primary stock solution (prepared in deionized water) was withdrawn from the toxicant reservoir, placed into 40 ml glass VOA vial, and transferred to analytical laboratory for determination of toxicant concentration.

Vehicle:

no

Details on test solutions:

Dilution water: 
Water use for acclimation of test organisms and for all toxicity testing was unfiltered seawater collected from the Atlantic Ocean at
EnviroSystems in Hampton, New Hampshire. Water, which had a salinity of 21 to 26 ppt (parts per thousand) and a pH of 7.7 to 8.0, was stored in 500-gallon polyethylene tanks where it was aerated. 

Stock solution:
An initial 500,000 mg/L stock solution was prepared by combining 1,000.0 g of test substance and deionized water in a 2 liter class A volumetric flask and adjusting the volume to approximately 1,950 ml with deionized water. The stock solution was mixed until the test substance dissolved on a magnetic stir plate and the total volume was brought up to 2.0 L with deionized water. This procedure was repeated three more times to produce a total of 6 L more of the 500,000 mg/L stock solution. 

Appropriate amounts of the stock solution were added directly to dilution water by a proportional diluter (5.0 ml of test substance was combined with 2,500 ml of water during each diluter cycle) and this diluter toxicant cell solution was mixed by a high shear pump equipped with a Teflon head.

Test organisms

Test organisms (species):

other: Crassostrea virginica

Details on test organisms:

Juvenile oysters employed as test organisms were from a single source and were identified using an appropriate taxonomic key. They were procured from the Aquatic Research Organisms division of Resource Analysts Inc. in Hampton, New Hampshire and acclimated to test conditions in unfiltered seawater for more than 10 days. Prior to testing oysters were maintained in 100% dilution water under flow through conditions. During acclimation oysters were not treated for disease and they were free of apparent sickness, injury, and abnormality at the beginning of the test. Oysters were supplied with live marine phytoplankton to supplement the available food in the unfiltered natural seawater that was used as dilution water and for acclimation. During the last 10 days of acclimation the temperature ranged from 18.6 - 21.2 °C, salinity was maintained at 25 to 26 parts per thousand, and dissolved oxygen was maintained above 7.4 mg/L.
Oysters were 25 to 50 mm in height (measured along the long axis). At the initiation of the test, each oyster was ground to remove approximately 3 to 5 mm of shell and form a smooth edge.

Study design

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Test temperature:

20.0 to 23.4°C

pH:

7.7 to 8.0

Dissolved oxygen:

7.2 to 7.5 mg/L

Salinity:

21 to 24 parts per thousand

Nominal and measured concentrations:

Nominal concentrations: 0 (control), 70, 120, 250, 500, and 1,000 mg/L sodium chlorate.
The 500,000 moiL (nominal) stock solution had a measured concentration of 480,000 mg/L sodium chlorate.

Details on test conditions:

- Photoperiod: A 16 hour light and 8 hour dark photoperiod was automatically maintained 
- Light intensity: with cool-white fluorescent lights that provided a light intensity of 18 pEs- 1/m2
- Aeration: Aeration was not required to maintain dissolved oxygen concentrations above acceptable levels. 
- Feeding: Oysters were supplied with live marine phytoplankton to supplement the available food in the unfiltered natural seawater that was used as dilution water.

Reference substance (positive control):

no

Results and discussion

Effect concentrationsopen allclose all

Effect concentrations 1

Duration:

96 h

Endpoint:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: shell growth

Effect concentrations 2

Duration:

96 h

Endpoint:

LC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

One hundred percent survival occurred in the control and no sublethal effects were noted during the exposure period. 
One oyster died in 250 mg/l, but this was not concentration related.

Reported statistics and error estimates:

Results of the toxicity test could not be interpreted by standard statistical techniques (Stephan, 1983) because greater than 50% control shell deposition occurred at all tested concentrations.

Any other information on results incl. tables:

Shell growth data from toxicity test with sodium chlorate

Conc. (mg/l)	0.0	70	120	250	500	1000
Mean (mm)	2.0	2.4	2.0	1.8	1.7	1.4
St. dev.	0.8	1.1	0.7	1.1	0.9	0.8
% of control	100.0	120.0	100.0	90.0	85.0	70.0

Applicant's summary and conclusion

Conclusions:

The 96h EC50 (based on shell growth) and LC50 were greater than the highest test concentration of 1000 mg/l.

Executive summary:

The effect of sodium chlorate on shell deposition by the eastern oyster, Crassostrea virginica , is described in this final report. The test was conducted for Albright and Wilson Americas for 96 hours during February 22 to 26, 1991, at the EnviroSystems Division of Resource Analysts, Inc. in Hampton, New Hampshire. It was conducted by Peter Kowalski, Ellen Stanford, Jeanne Magazu, Robert Boeri, and Timothy Ward according to the protocol developed for EnviroSystems Study Number 90116-DE. The analytical portion of this study was conducted under the supervision of Gloria Switalski. Sodium chlorate (reported purity >= 99% active ingredient) was supplied by the sponsor. The test was performed under flow-through conditions with five concentrations of test substance and a dilution water control at a temperature of 15 to 30°C. The dilution water was unfiltered natural seawater collected at Hampton, New Hampshire. Nominal concentrations of sodium chlorate were: 0 mg/L (control), 70, 120, 250, 500, and 1,000 mg/L. Nominal concentrations were used for all calculations. Oysters used in the test were procured from a commercial supplier (the Aquatic Research Organisms division of Resource Analysts, Inc., Hampton, New Hampshire) and acclimated under test conditions for more than 10 days. All animals were in good condition at the beginning of the study. Exposure of oysters to the test substance resulted in a 96 hour EC50 greater than 1,000 mg/L sodium chlorate.

Validity criteria fulfilled:

no data