Calcium carbonate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Bulk calcium carbonate and uncoated nano calcium carbonate are chemically identical. The only difference between them is the particle size, which may result in minor differences in physico-chemical properties. However, in biological systems and in the environment, both bulk and uncoated nano calcium carbonate are expected to have identical (eco)toxicological and environmental fate properties.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Uncoated nano calcium carbonate (Source): Refer to IUCLID section 1.2 for information on purity and impurities.
Bulk calcium carbonate (Target): Refer to IUCLID section 1.2 for information on purity and impurities.
The majority of new studies have been performed using uncoated nano calcium carbonate as the test material, hence it has been designated as the ‘Source’ in the read-across justification. However, for some endpoints data on bulk calcium carbonate are available and used to read-across to uncoated nano calcium carbonate so for these endpoints, marked with a * in the read-across justification document, bulk calcium carbonate is the ‘Source’.
3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the justification attached in Section 13 of the dataset
4. DATA MATRIX
Please refer to the justification attached in Section 13 of the dataset

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

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

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

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

other: saturated solution of test material

Basis for effect:

other: zero immobilisation

Description of key information

The acute toxicity of uncoated nano calcium carbonate to Daphnia magna has been investigated in a GLP study performed in accordance with OECD TG 202. The 48 h EC50 was >100% v/v saturated solution and the NOEC was 100% v/v saturated solution.

The results from this study demonstrate that uncoated nano calcium carbonate is not acutely toxic to aquatic invertebrates at the limit of its solubility in water. This result is read across to bulk calcium carbonate.

Additional information

No data are available for bulk calcium carbonate. A study is available for uncoated nano calcium carbonate. This study, performed to OECD TG 202, assessed the acute toxicity of uncoated nano calcium carbonate to Daphnia magna in a limit test (Priestly, 2010). No toxic effects were seen when a 100% v/v saturated solution of calcium carbonate was tested. Hence, the 48 h EC50 was >100% v/v saturated solution and the NOEC was 100% v/v saturated solution. The concentration of uncoated nano calcium carbonate that might cause acute toxicity is therefore greater than the maximum solubility of calcium carbonate in water.

Uncoated nano calcium carbonate was tested because it was anticipated to represent the worst case as it is likely to be more soluble than bulk calcium carbonate due to the smaller particle size and hence greater surface area. However, the results are directly applicable to bulk calcium carbonate.

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