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Short-term toxicity to aquatic invertebrates

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For invertebrates, 43 individual reliable acute toxicity data points for two different species were put forward for hazard assessment purposes. The acute toxicity values (48h-LC50) for Ceriodaphnia dubia varied between of 26.4 µg dissolved Pb/L (at pH 8.1 and hardness of 25 mg/L) and 3115.8 µg dissolved Pb/L (at pH 8.15 and hardness of 103.2 mg/L).The acute toxicity values (48h-LC50) for Daphnia magna varied between of 107.0 µg dissolved Pb/L (at pH 8.3 and hardness of 152 mg/L) and 108.8 µg dissolved Pb/L (at pH 7.6 and hardness of 54 mg/L).

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Additional information

Pyrochlore:

The overall chemical and physiological properties of pyrochlore are principally characterised by a degree of inertness because of the specific synthetic process (calcination at high temperatures, approximately 1000°C), rendering the substance to be of a unique, stable crystalline structure in which the majority of atoms are tightly bound and not prone to dissolution in environmental and physiological media. This has been shown in transformation/dissolution testing for antimony, in which dissolved Sb concentrations were below 27 µg/L (after 7 days at a loading of 0.1g/L) and 2 µg/L (after 28 days at a loading of 1 mg/L); thus implying a solubility of < 0.03% of antimony. Hence, Sb can be considered as not bioavailable and is not regarded concerning toxicological and environmental effects.

On the other hand, lead dissolution levels were much higher (>2.9 mg/L at a loading of 100 mg/L after 7 days at pH 6; 105 µg/L at a loading of 1 mg/L after 28 days at pH 6) and therefore have to be regarded concerning toxicological and environmental aspects. No substance-specific data on the toxicity of pyrochlore are available, so that instead read-across to lead oxide and sparingly soluble lead compounds was conducted

Lead:

For invertebrates, 43 individual reliable acute toxicity data points for two different species were put forward for hazard assessment purposes. The acute toxicity values (48h-LC50) for Ceriodaphnia dubia varied between of 26.4 µg dissolved Pb/L (at pH 8.1 and hardness of 25 mg/L) and 3115.8 µg dissolved Pb/L (at pH 8.15 and hardness of 103.2 mg/L).The acute toxicity values (48h-LC50) for Daphnia magna varied between of 107.0 µg dissolved Pb/L (at pH 8.3 and hardness of 152 mg/L) and 108.8 µg dissolved Pb/L (at pH 7.6 and hardness of 54 mg/L).