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Sediment toxicity

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Description of key information

The high quality chronic freshwater sediment database contains toxicity data towards lead for 7 different sediment dwelling species (Tubifex tubifex, Ephoron virgo, Hyalella azteca, Gammarus pulex, Lumbriculus variegatus, Hexagenia limbata, Chironomus tentans). Selected no-effect levels for lead were situated between 573 mg Pb/kg (Tubifex tubifex; endpoint: reproduction) and 3390 mg Pb/kg (Chironomus tentans; endpoint: survival). The chronic toxicity database for marine sediment dwelling organisms contains toxicity data for 2 marine species (Neanthes arenaceodentata and Leptocheirus plumulosus). Selected no-effect levels for lead were situated between 680 mg Pb/kg (Neanthes arenaceodentata; endpoint: growth) and 1291 mg Pb/kg (Leptocheirus plumulosus; endpoint: growth)

Key value for chemical safety assessment

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:

The high quality chronic freshwater sediment database contains toxicity data towards lead for 7 different sediment dwelling species (Tubifex tubifex, Ephoron virgo, Hyalella azteca, Gammarus pulex, Lumbriculus variegatus, Hexagenia limbata, Chironomus tentans). Selected no-effect levels for lead were situated between 573 mg Pb/kg (Tubifex tubifex; endpoint: reproduction) and 3390 mg Pb/kg (Chironomus tentans; endpoint: survival). The chronic toxicity database for marine sediment dwelling organisms contains toxicity data for 2 marine species (Neanthes arenaceodentata and Leptocheirus plumulosus). Selected no-effect levels for lead were situated between 680 mg Pb/kg (Neanthes arenaceodentata; endpoint: growth) and 1291 mg Pb/kg (Leptocheirus plumulosus; endpoint: growth).