Calcium magnesium strontium carbonate hydroxide phosphate (4.3-4.7 : 0.1-0.3: 0.2-0.5 : 0.3-0.5 : 0.2-0.6 : 3)

Endpoint summary

Description of key information

Daphnia-short term toxicity study

EC50 (48hr) > 100 mg/l (nominal) - EC50 (48hr) > 2.9 mg/l (measured) - Similar Substance 06

EC50 (48 hr) >100 mg/l (nominal) - EC50 (48 hr) >5.35 mg/l (measured) - Similar Substance 05

Daphnia-long term toxicity study

EC50 (3 weeks, reproductive impairment) = 60000 μg/l - strontium

EC50 (3 weeks, reproductive impairment) = 125000 μg/l - magensium

Toxicity to aquatic algae

EC50 (72hr) > 100 mg/l (nominal) - EC50 (72hr) > 1.56 mg/l (measured) - Similar Substance 05

EC50 (72hr) > 100 mg/l (nominal) - EC50 (72hr) > 4.4 mg/l (measured) - Similar Substance 06

IC50 (72h) = 1215 mg/l - magnesium (measured)

IC20 (72h) = 47000 µg/l - strontium

Additional information

The aquatic toxicity of the substance to aquatic organisms (aquatic invertebrates and algae) is evaluated by considerind data on similar substances. Justification for Read Across is given in Section 13 of IUCLID.

Short-term toxicity to aquatic invertebrates

The toxic potential of the similar substances to aquatic invertebrates is evaluated after the exposure of Daphnia magna at the substance for 48 hours, according to the OECD Guideline 202. No immobility or adverse effects were observed at control or 100 mg/l (nominal). The 48 hr EC50 of the two substances were both above the highest tested nominal concentration (100 mg/l) which corresponds to 2.9 mg/l (Similar Substance 06) and 5.35 mg/l (Similar Substance 05) measured concentrations.

The magnesium and strontium toxicity potential was also reported in the literature as LD50 of 140000 and 125000 μg/l corresponding to magnesium and strontium respectively. Ten daphnids were exposed to the substance for 48 hours after which they were observed for mortality and immobilisation

Long-term toxicity to aquatic invertebrates

The chronic toxicity of the metal ions to Daphnia magna was evaluated after the exposure of the organisms to the substances for 3 weeks. Twenty daphnids divided in four test chambers were exposed to concentrations ranging from 5 to 12 depending on the toxicant and the initial effects observed. At metal concentrations permiting survival but impairing reproduction, daphnids weighed less than control animals. The decrease (16 % and 50 %) in the number of young born (reproductive impairment) and the LC50 were evaluated.

Decrease in animal weight and increase in the percentage of protein per animal and on GOT activity was notably greater with Magnesium and Strontium addition.

EC16 (3weeks,reproductive impairment) = 82000 μg/l (nominal), EC50 (3weeks,reproductive impairment) = 125000 μg/l (nominal), LC50 = 190000 μg/l (nominal) - magensium)

EC16 (3weeks,reproductive impairment) = 42000 μg/l (nominal), EC50 (3weeks,reproductive impairment) = 60000 μg/l (nominal), LC50 = 86000 μg/l (nominal) - strontium

Toxicity to aquatic algae and cyanobacteria

The toxic potential of the substances to aquatic algae was evaluated according to the OECD Guideline 201 after a 72 -hr exposure of Pseudokirchneriella subcapitata to Similar Substance 05 at 0, 4, 9, 21, 45, and 100 mg/l (nominal) and to Similar Substance 06 at 0.3, 1, 3.1, 9.8, 31.3, and 100 mg/l. Analytical results indicated that the test substance was sparsely soluble in water. Morphological changes of algal cells were observed including expansion, aggregation, atrophy, and decoloration at 72 hours after exposure. Based on average specific growth rate and yield:

EC50 (72hr) > 100 mg/l (nominal) - Similar Substance 05 and Similar Substance 06

EC50 (72hr) > 4.4 mg/l (measured) - Similar Substance 06

EC50 (72hr) > 1.56 mg/l (measured) - Similar Substance 05

For strontium, the 72-h IC10 was 36000 µg/l and the IC20 was 47000 µg/l as determined in the standard 72-h algal growth test with the alga Pseudokirchneriella subcapitata.

Magnesium toxicity was also determined after a 72 -hr exposure of Chlorella sp. to 3 -1200 mg/l of magnesium sulfate.

Based on growth rate the following rates were determined:

IC50 (72h) = 1215 mg/l - Mg(measured), IC50 (72h) = 6014 mg/l -MgSO₄(measured)

IC10 (72h) = 43 mg/l - Mg(measured), IC10 (72h) = 213 mg/l - MgSO₄(measured)

The substance is poorly soluble in water rendering its bioavailability lower than the similar substances. It could thus be expected that the aquatic organisms will be exposed in a less extent to the substance and therefore the effect concentrations will be much higher.

JUSTIFICATION FOR CLASSIFICATION

The substance's biodegradation is not tested as the evaluation of this process is not relevant for inorganic substances. In any case, for classification purposes the worst-case scenario, i.e. the substance is not-readily biodegradable is considered.

Based on Annex I: Table 4.1.0 of the CLP Regulation (EC) No.1272/2008, and considering the effect concentrations reported in the literature for the similar substances, it is concluded that the substance should not be classified for aquatic toxicity according to the CLP Regulation (EC) No.1272/2008.