Short-term toxicity to aquatic invertebrates.011

Short-term toxicity to aquatic invertebrates.011

Administrative data

Purpose flag:

weight of evidence

Study result type:

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

The test substance could not be monitored in the test solutions due to background interference. However, the method allowed accurate determination of the stock solution concentrations in deionised water. As a flow-through system was used, the nominals are considered acceptable estimates of the actual concentrtation.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

EPA OPP 72-3 (Estuarine/Marine Fish, Mollusk, or Shrimp Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. certificate)

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:

Further relevant properties: A fine white powder
- 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: no data
- Physical state: fine powder
- Analytical purity: 80 %
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components: no data
- Isomers composition: not applicable
- Purity test date: 1991-05-07
- Lot/batch No.: 09-M, PAL M-03, 75A/PAL A-300
- Expiration date of the lot/batch: no data
- Stability under test conditions:
- Storage condition of test material: stored in the dark 2-4°C

Details on properties of test surrogate or analogue material:

no data

Analytical monitoring:

yes

Details on sampling:

Dissolved oxygen, pH, salinity and temperature were recorded for each test chamber. The temperature in one test vessel was recorded continuously during the test.

Vehicle:

no

Details on test solutions:

not applicable

Test organisms

Test organisms (species):

Mysidopsis bahia (new name: Americamysis bahia)

Details on test organisms:

TEST ORGANISM
- Common name: Mysids
- Strain: no data
- Source: EnviroSystems in Hampton, New Hampshire
- Age at study initiation (mean and range, SD): less than 24 hours
- Weight at study initiation (mean and range, SD): no data
- Length at study initiation (length definition, mean, range and SD): no data
- Valve height at study initiation, for shell deposition study (mean and range, SD): no data
- Peripheral shell growth removed prior to test initiation: no data
- Method of breeding: Mysids were fed with newly hatched Artemia salina nauplii (EnviroSystems lot number BS02)
- Feeding during test: Yes 
- Food type: Artemia salina nauplii (EnviroSystems lot number BS02)
- Amount: no data
- Frequency: one per day

ACCLIMATION
- Acclimation period: no data
- Acclimation conditions (same as test or not): no data
- Type and amount of food: Mysids were fed with newly hatched Artemia salina nauplii (EnviroSystems lot number BS02)
- Feeding frequency: once or twice daily
- Health during acclimation (any mortality observed): Mysids were not treated for disease and they were free of apparent sickness, injuries, and abnormalities at the beginning of the test.

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

Study design

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Test temperature:

22 ± 1 °C

pH:

7.8 - 8.2

Dissolved oxygen:

7.3 - 8.0 mg/L

Salinity:

11-17 ppt

Nominal and measured concentrations:

Nominal concentrations were 0, 0.15, 0.25, 0.40, 0.60, 1.00 mg sodium chlorite/L
(Doses are equivalent to 0, 0.11, 0.19, 0.30, 0.45 and 0.75 mg chlorite/L)

Details on test conditions:

TEST SYSTEM
- Test vessel: 20 L glass aquaria
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 15 L of test solution
- Aeration: No
- Type of flow-through (e.g. peristaltic or proportional diluter): proportional diluter
- Renewal rate of test solution (frequency/flow rate): 6.6 media exchanges per 24 hours in each test vessel.
- No. of organisms per vessel: 20
- No. of vessels per concentration (replicates): 2 
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): not applicable
- Biomass loading rate: no data

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16:8
- Light intensity: 12 µES-1/m²

Reference substance (positive control):

no

Results and discussion

Effect concentrationsopen allclose all

Effect concentrations 1

Duration:

96 h

Endpoint:

EC0

Remarks:

and NOEC

Effect conc.:

0.25 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

96 h

Endpoint:

EC0

Remarks:

and NOEC

Effect conc.:

0.19 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

96 h

Endpoint:

EC50

Effect conc.:

0.65 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks (e.g. 95% CL):

95% confidence interval of 0.40 – 1.00 mg/L

Effect concentrations 4

Duration:

96 h

Endpoint:

EC50

Effect conc.:

0.49 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Lethargy was noted in the 1.00 mg/L treatment group between 48 and 72 h.

Results with reference substance:

not applicable

Reported statistics and error estimates:

no data

Any other information on results incl. tables:

Table A7_4_1_2(4)-6:        Immobilisation data: mysids living

Test Substance Concentration (nominal) [mg sodium chlorite/L]	Replicate	0 h	24 h	48 h	72 h	96 h
0 (Control)	1	10	10	10	10	9
	2	10	10	10	10	9
0.15	1	10	10	10	10	10
	2	10	10	10	10	9
0.25	1	10	10	10	10	10
	2	10	10	10	10	10
0.40	1	10	10	10	8	8
	2	10	10	10	9	7
0.60	1	10	10	7	5	5
	2	10	10	9	7	7
1.00	1	10	8	3	1	0
	2	10	8	3	1	1

Table A7_4_1_2(1)-7:        Immobilisation data: lethargic mysids

Test Substance Concentration (nominal) [mg sodium chlorite/L]	Replicate	0 h	24 h	48 h	72 h	96 h
0 (Control)	1	0	0	0	0	0
	2	0	0	0	0	0
0.15	1	0	0	0	0	0
	2	0	0	0	0	0
0.25	1	0	0	0	0	0
	2	0	0	0	0	0
0.40	1	0	0	0	0	0
	2	0	0	0	0	0
0.60	1	0	0	0	0	0
	2	0	0	0	0	0
1.00	1	0	0	3	1	-
	2	0	0	3	1	0

Table A7_4_1_2(4)-8:        Effect data

Exposure Period	Median LC50	95 % c.l.	LC50 Calculation Method
24 h [mg sodium chlorite/L]	>1.00 mg/L (n)	-	-
48 h [mg sodium chlorite/L]	0.83 mg/L (n)	0.72 – 1.00 mg/L	Probit
72 h [mg sodium chlorite/L]	0.66 mg/L (n)	0.40 – 1.00 mg/L	Binomial / nonlinear interpolation
96 h [mg sodium chlorite/L]	0.65 mg/L (n)	0.40 – 1.00 mg/L	Binomial / nonlinear interpolation

Applicant's summary and conclusion

Conclusions:

Exposure of mysids to the test substance resulted in a 96 h LC50 of 0.65 mg/L of sodium chlorite, with a 95% confidence interval of 0.40 – 1.00 mg/L (equivalent to 0.49 mg chlorite/L). The 96 h NOEC was 0.25 mg/L sodium chlorite (equivalent to 0.19 mg chlorite/L).

Executive summary:

Mysids, Mysidopsis bahia, have been exposed to sodium chlorite acute toxicity test, following US EPA procedures (1985, 1988), under GLP. Five chlorite nominal concentrations were tested: 0.15, 0.25, 0.40, 0.60, and 1.00 mg/L in duplicates for 96 hours. Each aquaria contained 10 mysids (n = 20 mysids per concentration). Exposure of mysids to the test substance resulted in an EC50(96h) = 0.65 mg/L of sodium chlorite; and a NOEC (96h) = 0.25 mg/L of sodium chlorite.