Synthetic wollastonite

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:

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

Adequacy of study:

key study

Study period:

The study was conducted between 04 May 2010 and 08 July 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

The use of data derived for Soda-ash flux calcined kieselghur are justified for read-across to
synthetic wollastonite. Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for Soda-ash flux calcined kieselghur and synthetic wollastonite.
Considering the available data:
The source substance show no concerns for the environment.
The source substance has low acute toxicity and low toxicity in repeated dose studies, is non-irritant (skin and eye), non-sensitizing, non-mutagenic to bacteria, non-cytogenic and has low toxicity for reproductive and developmental toxicity.
Please see RAAF attached in Section 13. for further details.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from the control (replicates R1 – R4 pooled) and the 100% v/v saturated solution test group (replicates R1 – R2 and R3 – R4 pooled) at 0 and 48 hours for quantitative analysis.
Duplicate samples were taken and stored at approximately -20°C for further analysis if necessary.

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Preliminary solubility work conducted indicated that the test item was practically insoluble in water using traditional methods of preparation e.g. ultrasonication and high shear mixing.
Based on this information the test item was categorised as being a ‘difficult substance’ as defined by the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (OECD 2000).
An amount of test item (550 mg) was dispersed in 11 litres of reconstituted water with the aid of a propeller stirrer at approximately 1500 rpm at a temperature of approximately 22°C for 24 hours. After the stirring period, the undissolved test item was removed by filtration through a 0.2 µm Gelman Acrocap filter (first approximate 100 ml discarded to pre-condition the filter) to give the 100% v/v saturated solution.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: In-house laboratory cultures.
- Age at study initiation: Less than 24 hours old
- Feeding during test: No
- Food type: Suspension of algae (Chlorella sp.)
- Frequency: Fed daily during culturing

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

The reconstituted water had an approximate theoretical total hardness of 250 mg/L as CaCO3.

Test temperature:

Control: 20 - 21°C
Test vessels: 21°C

pH:

Control: 8.0 - 8.2
Test vessels: 7.9 - 8.2

Dissolved oxygen:

Control: 97-102% ASV (air saturation value)
Test vessels: 97-99% ASV

Nominal and measured concentrations:

Nominal concentration: 100% v/v saturated solution of test material

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: closed
- Material, size, headspace, fill volume: 250 mL glass jars
- Aeration: Not during the test. During preparation, the reconstituted water was aerated until the dissolved oxygen concentration was approximately air-saturation value.
- No. of organisms per vessel: 5 daphnids/ vessel
- No. of vessels per concentration (replicates): 4 replicates/concentration
- No. of vessels per control (replicates): 4 replicates


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water
- Conductivity: <5 µS cm-1
- Culture medium different from test medium: No
- Intervals of water quality measurement: Water temperature was recorded daily throughout the test. Dissolved oxygen concentrations and pH were recorded at the start and termination of the test.

OTHER TEST CONDITIONS
- Adjustment of pH: Only if necessary during preparation of the reconstituted water, with NaOH or HCl (to pH 7.8 ± 0.2)
- Photoperiod: 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Any immobilisation or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that Daphnia were considered to be immobilised if they were unable to swim for approximately 15 seconds after gentle agitation.

TEST CONCENTRATIONS
- Justification for using less concentrations than requested by guideline: Based on the results of the range-finding test a limit test was conducted at a concentration of 100% v/v saturated solution to confirm that at the highest attainable test concentration, no immobilisation or adverse reactions to exposure were observed.
- Range finding study
- Test concentrations: 0.10, 1.0, 10 and 100% v/v saturated solution of test material
- Results used to determine the conditions for the definitive study: No immobilisation was observed at any of the test concentrations. Based on this information a single test concentration of 100% v/v was selected for the definitive test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/l.

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

other: saturated solution of test material

Details on results:

There was no immobilisation in 20 daphnids exposed to a test concentration of 100% v/v saturated solution for a period of 48 hours.

The test preparations were observed to be clear, colourless solutions throughout the duration of the test.

Results with reference substance (positive control):

24 h EC50: 0.84 mg/L (95% confidence limits 0.72-0.97 mg/L)
48 h EC50: 0.65 mg/L (95% confidence limits 0.58-0.72 mg/L)
48 h NOEC: 0.32 mg/L

Table 1: Cumulative Immobilisation Data in the Range-finding Test

Nominal Concentration (% v/v Saturated Solution)	Cumulative ImmobilisedDaphnia (Initial Population: 10 Per Replicate)
	24 Hours	48 Hours
Control	0	0
0.10	0	0
1.0	0	0
10	0	0
100	0	0

Table 2: Cumulative Immobilisation Data in the Definitive Test

Nominal Concentration (% v/v Saturated Solution)		Cumulative Immobilised Daphnia (Initial Population: 5 Per Replicate)
		24 Hours			48 Hours
		No. Per Replicate	Total	%	No. Per Replicate	Total	%
Control	R1	0	0	0	0	0	0
	R2	0			0
	R3	0			0
	R4	0			0
100	R1	0	0	0	0	0	0
	R2	0			0
	R3	0			0
	R4	0			0

R₁– R₄= Replicates 1 to 4

Table 3: Cumulative Immobilisation Data in the Positive Control

Nominal Concentration (mg/l)	Cumulative Immobilised Daphnia (Initial Population: 10 Per Replicate)
	24 Hours				48 Hours
	R1	R2	Total	%	R1	R2	Total	%
Control	0	0	0	0	0	0	0	0
0.32	0	0	0	0	0	0	0	0
0.56	1	1	2	10	3	2	5	25
1.0	7	7	14	70	10	10	20	100
1.8	10	10	20	100	10	10	20	100
3.2	10	10	20	100	10	10	20	100

Table 4: Physico-chemical measurements

Nominal Concentration (% v/v Saturated Solution)		0 Hours				24 Hours	48 Hours
		pH	mg O2/l	%*	T°C	TºC	pH	mg O2/l	%*	T°C
Control	R1	8.0	9.3	102	20	20	8.1	8.6	97	21
	R2	8.0	9.3	102	20	20	8.1	8.6	97	21
	R3	8.0	9.3	102	20	20	8.1	8.6	97	21
	R4	8.0	9.3	102	20	20	8.2	8.6	97	21
100	R1	7.9	8.8	99	21	20	8.2	8.6	97	21
	R2	7.9	8.7	98	21	20	8.2	8.6	97	21
	R3	7.9	8.7	98	21	20	8.2	8.6	97	21
	R4	7.9	8.8	99	21	20	8.2	8.6	97	21

*ASV= Dissolved oxygen concentration expressed as a percentage of Air Saturation Value

R₁– R₄= Replicates 1 to 4

Validity criteria fulfilled:

yes

Remarks:

All validity criteria were satisfied

Conclusions:

The acute toxicity of the analogue substance soda-ash flux calcined kieselguhr to Daphnia magna has been investigated and gave a 48 h EC50 of >100% v/v saturated solution. The NOEC was 100% v/v saturated solution.
Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for Soda-ash flux calcined kieselghur and synthetic wollastonite.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 04 May 2010 and 08 July 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from the control (replicates R1 – R4 pooled) and the 100% v/v saturated solution test group (replicates R1 – R2 and R3 – R4 pooled) at 0 and 48 hours for quantitative analysis.
Duplicate samples were taken and stored at approximately -20°C for further analysis if necessary.

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Preliminary solubility work conducted indicated that the test item was practically insoluble in water using traditional methods of preparation e.g. ultrasonication and high shear mixing.
Based on this information the test item was categorised as being a ‘difficult substance’ as defined by the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (OECD 2000).
An amount of test item (550 mg) was dispersed in 11 litres of reconstituted water with the aid of a propeller stirrer at approximately 1500 rpm at a temperature of approximately 22°C for 24 hours. After the stirring period, the undissolved test item was removed by filtration through a 0.2 µm Gelman Acrocap filter (first approximate 100 ml discarded to pre-condition the filter) to give the 100% v/v saturated solution.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: In-house laboratory cultures.
- Age at study initiation: Less than 24 hours old
- Feeding during test: No
- Food type: Suspension of algae (Chlorella sp.)
- Frequency: Fed daily during culturing

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

The reconstituted water had an approximate theoretical total hardness of 250 mg/L as CaCO3.

Test temperature:

Control: 20 - 21°C
Test vessels: 21°C

pH:

Control: 8.0 - 8.2
Test vessels: 7.9 - 8.2

Dissolved oxygen:

Control: 97-102% ASV (air saturation value)
Test vessels: 97-99% ASV

Nominal and measured concentrations:

Nominal concentration: 100% v/v saturated solution of test material

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: closed
- Material, size, headspace, fill volume: 250 mL glass jars
- Aeration: Not during the test. During preparation, the reconstituted water was aerated until the dissolved oxygen concentration was approximately air-saturation value.
- No. of organisms per vessel: 5 daphnids/ vessel
- No. of vessels per concentration (replicates): 4 replicates/concentration
- No. of vessels per control (replicates): 4 replicates


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water
- Conductivity: <5 µS cm-1
- Culture medium different from test medium: No
- Intervals of water quality measurement: Water temperature was recorded daily throughout the test. Dissolved oxygen concentrations and pH were recorded at the start and termination of the test.

OTHER TEST CONDITIONS
- Adjustment of pH: Only if necessary during preparation of the reconstituted water, with NaOH or HCl (to pH 7.8 ± 0.2)
- Photoperiod: 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Any immobilisation or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that Daphnia were considered to be immobilised if they were unable to swim for approximately 15 seconds after gentle agitation.

TEST CONCENTRATIONS
- Justification for using less concentrations than requested by guideline: Based on the results of the range-finding test a limit test was conducted at a concentration of 100% v/v saturated solution to confirm that at the highest attainable test concentration, no immobilisation or adverse reactions to exposure were observed.
- Range finding study
- Test concentrations: 0.10, 1.0, 10 and 100% v/v saturated solution of test material
- Results used to determine the conditions for the definitive study: No immobilisation was observed at any of the test concentrations. Based on this information a single test concentration of 100% v/v was selected for the definitive test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/l.

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

other: saturated solution of test material

Details on results:

There was no immobilisation in 20 daphnids exposed to a test concentration of 100% v/v saturated solution for a period of 48 hours.

The test preparations were observed to be clear, colourless solutions throughout the duration of the test.

Results with reference substance (positive control):

24 h EC50: 0.84 mg/L (95% confidence limits 0.72-0.97 mg/L)
48 h EC50: 0.65 mg/L (95% confidence limits 0.58-0.72 mg/L)
48 h NOEC: 0.32 mg/L

Table 1: Cumulative Immobilisation Data in the Range-finding Test

Nominal Concentration (% v/v Saturated Solution)	Cumulative ImmobilisedDaphnia (Initial Population: 10 Per Replicate)
	24 Hours	48 Hours
Control	0	0
0.10	0	0
1.0	0	0
10	0	0
100	0	0

Table 2: Cumulative Immobilisation Data in the Definitive Test

Nominal Concentration (% v/v Saturated Solution)		Cumulative Immobilised Daphnia (Initial Population: 5 Per Replicate)
		24 Hours			48 Hours
		No. Per Replicate	Total	%	No. Per Replicate	Total	%
Control	R1	0	0	0	0	0	0
	R2	0			0
	R3	0			0
	R4	0			0
100	R1	0	0	0	0	0	0
	R2	0			0
	R3	0			0
	R4	0			0

R₁– R₄= Replicates 1 to 4

Table 3: Cumulative Immobilisation Data in the Positive Control

Nominal Concentration (mg/l)	Cumulative Immobilised Daphnia (Initial Population: 10 Per Replicate)
	24 Hours				48 Hours
	R1	R2	Total	%	R1	R2	Total	%
Control	0	0	0	0	0	0	0	0
0.32	0	0	0	0	0	0	0	0
0.56	1	1	2	10	3	2	5	25
1.0	7	7	14	70	10	10	20	100
1.8	10	10	20	100	10	10	20	100
3.2	10	10	20	100	10	10	20	100

Table 4: Physico-chemical measurements

Nominal Concentration (% v/v Saturated Solution)		0 Hours				24 Hours	48 Hours
		pH	mg O2/l	%*	T°C	TºC	pH	mg O2/l	%*	T°C
Control	R1	8.0	9.3	102	20	20	8.1	8.6	97	21
	R2	8.0	9.3	102	20	20	8.1	8.6	97	21
	R3	8.0	9.3	102	20	20	8.1	8.6	97	21
	R4	8.0	9.3	102	20	20	8.2	8.6	97	21
100	R1	7.9	8.8	99	21	20	8.2	8.6	97	21
	R2	7.9	8.7	98	21	20	8.2	8.6	97	21
	R3	7.9	8.7	98	21	20	8.2	8.6	97	21
	R4	7.9	8.8	99	21	20	8.2	8.6	97	21

*ASV= Dissolved oxygen concentration expressed as a percentage of Air Saturation Value

R₁– R₄= Replicates 1 to 4

Validity criteria fulfilled:

yes

Remarks:

All validity criteria were satisfied

Conclusions:

The acute toxicity of soda-ash flux calcined kieselguhr to Daphnia magna has been investigated and gave a 48 h EC50 of >100% v/v saturated solution. The NOEC was 100% v/v saturated solution.

Description of key information

An acute toxicity study to Daphnia magna has not been carried out on Synthetic Wollastonite. A study has been carried out on the analogue substance kieselguhr soda ash flux calcined  The study was carried out to GLP in accordance with OECD Guideline 202. The 48 h EC50 was >100% v/v saturated solution and the NOEC was 100% v/v saturated solution.

Additional information

The key study (Priestly 2010) was performed to OECD Guideline 202 and in accordance with GLP. The study assessed the acute toxicity to Daphnia magna in a limit test. Pre-study solubility work indicated that a solution of the test item could not be attained using conventional methods, for example, ultrasonication or high shear mixing. Given the insoluble nature of the test item and also its high purity value, it was considered that the most suitable method of preparation was as a saturated solution.

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at a concentration of 100 % v/v saturated solution for 48 hours. Immobilisation and any adverse reactions to exposure were recorded after 24 and 48 hours. The 48-Hour EC₅₀for the test item to Daphnia magna based on nominal test concentrations was greater than 100 % v/v saturated solution and correspondingly the No Observed Effect Concentration was 100 % v/v saturated solution.

Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for Soda-ash flux calcined kieselghur and synthetic wollastonite.