Sodium chlorite

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

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 concentration.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Test organisms (species):

other aquatic crustacea: Eastern Oyster (Crassostrea virginica)

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

20.4 - 21.2 °C

pH:

7.5 - 9.2

Dissolved oxygen:

7.0 - 8.3 mg/L

Nominal and measured concentrations:

Nominal concentrations of the active substance were 0 (control), 70.6, 121, 252, 504 and 1008 mg sodium chlorite/L(Doses are equivalent to 0, 53, 90, 188, 376 and 752 mg chlorite/L)

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

EC0

Remarks:

and NOEC

Effect conc.:

70.6 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: shell deposition

Key result

Duration:

96 h

Dose descriptor:

EC0

Remarks:

and NOEC

Effect conc.:

53 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: shell deposition

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

129 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: shell deposition

Remarks on result:

other: 95% confidence interval of 121 – 138 mg/L

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

96 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: shell deposition

Details on results:

No sub-lethal effects were noted during the exposure period however, after 72 h large and approximately equal amounts of faecal material were present in the control and at 70.6 and 121 mg/L sodium chlorite. The volume of fecal material at concentrations above 121 mg/L appeared to decrease with increasing toxicant concentration.
Shell deposition by oysters was related to the concentration of test substance.
Exposure of the oysters to sodium chlorite resulted in a 96 h EC50 of 129 mg/L sodium chlorite with a 95% confidence interval of 121 – 138 mg/L (equivalent to 96 mg chlorite/L).
The 96 h NOEC was 70.6 mg/L sodium chlorite (equivalent to 53 mg chlorite/L).

Table A7_4_1_2(5)-5:        Immobilisation data: Number of live oysters

Test-Substance Concentration (Nominal) [mg sodium chlorite/L]	0 h	24 h	48 h	72 h	96 h
0 (control)	20	20	20	20	20
70.6	20	20	20	20	20
121	20	20	20	20	20
252	20	20	20	20	19
504	20	20	20	20	13
1008	20	20	20	20	2

Table A7_4_1_2(5)-6:        Shell growth at longest finger (mm)

Oyster Number	0.0 mg/l	70.6 mg/l	121 mg/l	252 mg/l	504 mg/l	1008 mg/l
1	2.2	1.9	1.3	0.0	0.0	0.0
2	2.1	1.7	1.0	0.0	0.0	0.0
3	1.9	2.2	1.2	0.0	0.0	-
4	2.4	2.4	1.6	0.2	0.0	-
5	2.1	2.3	1.4	0.0	0.0	-
6	2.1	2.0	1.3	0.0	0.0	-
7	2.3	2.1	1.0	0.1	0.0	-
8	1.9	2.2	0.9	0.0	0.0	-
9	2.3	1.9	1.4	0.0	0.0	-
10	2.2	2.2	1.5	0.0	0.0	-
11	2.0	2.4	1.3	0.0	0.0	-
12	2.4	2.0	1.6	0.0	0.0	-
13	2.0	2.1	1.0	0.1	-	-
14	2.1	2.1	0.7	0.1	-	-
15	2.1	1.7	0.8	0.0	-	-
16	1.8	2.3	1.1	0.0	-	-
17	1.7	2.4	0.9	00	-	-
18	2.2	1.8	1.3	0.0	-	-
19	2.4	2.1	1.2	0.0	-	-
20	2.1	2.0	1.0	0.0	-	-
Mean	2.1	2.1	1.2	0.1	0.0	0.0
Std. dev.	0.2	0.2	0.3	0.1	-	-
% of control	100	100	57.1	1.4	0.0	0.0

Table A7_4_1_2(5)-7:        Effect data

	EC50	95 % c.l.	EC0
96 h [mg sodium chlorite/L]	129 mg/L (n^1)	121 – 138 mg/l	70.6 mg/l

¹ Effect data are based on nominal (n) concentrations

Conclusions:

Exposure of the oysters to sodium chlorite resulted in a 96 h EC50 of 129 mg/L sodium chlorite with a 95% confidence interval of 121 – 138 mg/L (equivalent to 96 mg chlorite/L). The 96 h NOEC was 70.6 mg/L sodium chlorite (equivalent to 53 mg chlorite/L).

Executive summary:

The aim of this study was to investigate the shell deposition of the Eastern Oyster crustacea produced by the test material.

The test procedure used was the EPA OPP 72-3 (Estuarine/Marine Fish, Mollusk, or Shrimp Acute Toxicity Test)

Nominal concentrations of the active substance were 0 (control), 70.6, 121, 252, 504 and 1008 mg sodium chlorite/L (Doses are equivalent to 0, 53, 90, 188, 376 and 752 mg chlorite/L)

The result was as follows:

Exposure of the oysters to sodium chlorite resulted in a 96 h EC50 of 129 mg/L sodium chlorite with a 95% confidence interval of 121 – 138 mg/L (equivalent to 96 mg chlorite/L). The 96 h NOEC was 70.6 mg/L sodium chlorite (equivalent to 53 mg chlorite/L).

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

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 concentration.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

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.

Test organisms (species):

Americamysis bahia (previous name: Mysidopsis bahia)

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

22 ± 1 °C

pH:

7.8 - 8.2

Dissolved oxygen:

7.3 - 8.0 mg/L

Nominal and measured concentrations:

Nominal 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)

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

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

Key result

Duration:

96 h

Dose descriptor:

EC0

Remarks:

and NOEC

Effect conc.:

0.19 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

0.65 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence interval of 0.40 – 1.00 mg/L

Key result

Duration:

96 h

Dose descriptor:

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.

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

Validity criteria fulfilled:

yes

Remarks:

(immobilisation in the control was 0%; the dissolved oxygen concentration at the end of the test was greater than 3 mg/l in control and test vessels).

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:

The aim of this study was to investigate the degree of inhibition of the Mysidopsis bahia mobility produced by the test material.

The test procedure used was the EPA OPP 72-3 (Estuarine/Marine Fish, Mollusk, or Shrimp Acute Toxicity Test)

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)

The result was as follows:

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).

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No GLP statement or analysis

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Principles of method if other than guideline:

The acute toxicity of sodium chlorite to Daphnia magna in a 48 hr static test was assessed.

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

Water quality parameters were tested, namely temperature, hardness, dissolved oxygen and pH at 0 hr and 48 hr for the control and highest concentration.

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

19.6 °C

pH:

7.91 - 8.45

Dissolved oxygen:

6.7 - 9.3 mg/L

Nominal and measured concentrations:

Nominal concentrations:1, 10 and 100 mg/L (expressed as active component)(Doses are equivalent to 0.75, 7.5 and 75 mg chlorite/L)

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

< 1 other: mg sodium chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

< 0.75 other: mg chlorite/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Table A7_4_1_2 (3)-6:       Cumulative immobilisation data

Test Substance Concentration (nominal)^1 [mg sodium chlorite/L]
	Immobile Daphnia
	Number     24 h          48 h		Percentage      24 h         48 h
0	0/5	0/5	0	0
	0/5	0/5	0	0
	0/5	0/5	0	0
	0/5/	0/5	0	0
1	4/5	5/5	80	100
	4/5	5/5	80	100
	1/5	5/5	20	100
	3/5	5/5	60	100
10	2/5	5/5	40	100
	4/5	5/5	80	100
	3/5	5/5	60	100
	3/5	5/5	60	100
100	5/5	5/5	100	100
	5/5	5/5	100	100
	5/5	5/5	100	100
	5/5	5/5	100	100

¹ Concentrations were nominal

Table A7_4_1_2 (3)-7:       Effect data

	EC50^1	95 % c.l.	EC0^1	EC100^1
24 h [mg sodium chlorite/L]	Not specified	Not specified	Not specified	Not specified
48 h [mg sodium chlorite/L]	1 mg/L (n)	Not specified	Not specified	7 mg/L

¹ effect data are based on nominal (n) concentrations

Validity criteria fulfilled:

yes

Remarks:

(immobilisation in the control was 0%; the dissolved oxygen concentration at the end of the test was greater than 3 mg/l in control and test vessels).

Conclusions:

The 48 hr EC50 < 1 mg sodium chlorite/L (equivalent to 0.75 mg chlorite/L).

Executive summary:

The aim of this study was to investigate the degree of inhibition of the Daphnia magna´s mobility produced by the test material.

The test procedure used was the OECD Guideline 202

Nominal concentrations: 1, 10 and 100 mg/L (expressed as active component) (Doses are equivalent to 0.75, 7.5 and 75 mg chlorite/L)

The result was as follows:

The 48 hr EC50 < 1 mg sodium chlorite/L (equivalent to 0.75 mg chlorite/L).

Description of key information

Key study. Test method OECD 202. The 48 hr-EC50 in Daphnia magna was < 1 mg sodium chlorite/L (equivalent to 0.75 mg chlorite/L).

Key study. Test method EPA OPP 72-3. The 96 h-LC50 in mysids was 0.65 mg/L of sodium chlorite (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).

Key study. Test method EPA OPP 72-3. The 96 h-EC50 in oysters was 129 mg/L sodium chlorite with a 95% (equivalent to 96 mg chlorite/L). The 96 h NOEC was 70.6 mg/L sodium chlorite (equivalent to 53 mg chlorite/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

0.65 mg/L