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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Key value for chemical safety assessment

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Studies specifically on algae toxicity of lead bis(tetrafluoroborate) do not exist. Since lead salts are well-examined and even one study for tetrafluoroborate salts exists which results in a NOEC of 103 mg/L, it was decided to read across from a soluble lead salt and a tetrafluoroborate salt in the forefront of the lead bis(tetrafluoroborate) dossier preparation for reasons already stated in the HH section.

Lead bis(tetrafluoroborate) is a soluble metal salt (> 500 g/L at 20°C; for more detailed information please refer to section 4.8 of this dossier). Read across is performed to the lead dichloride dossier (water solubility 10g/L at 20°C) and triethylmethylammonium tetrafluoroborate (> 2000 g/L at 20°C). It is explicitly noted here that the submitter of this dossier has obtained formal access to the lead dichloride dossier.

As stated above, the NOEC value for the acute algae toxicity of triethylmethylammonium tetrafluoroborate in algae is 103 mg/L.

For algae, 7 individual reliable freshwater acute toxicity data for various lead salts for one species were put forward for hazard assessment purposes. The acute toxicity values (48h-EC50) for Pseudokirchneriella subcapitata varied between of 21.7 µg dissolved Pb/L (at pH 7.5 and hardness of 24.2 mg/L) and 322.9 µg dissolved Pb/L (at pH 7.3 and hardness of 174.4 mg/L). 2 different chronic high quality no-effect levels for dissolved lead for freshwater algae situated between 34.1µg Pb/L and 93.0 µg Pb/L (Pseudokirchneriella subcapitata) were observed. High quality no-effect levels for dissolved lead for marine algae plants were situated between 52.9 µg Pb/L (Skeletonema costatum; endpoint: yield) and 1231.8 µg Pb/L (Dunaliella tertiolecta; endpoint: growth rate).

By using the lowest value of all these data, it can be concluded that for lead bis(tetrafluoroborate), the EC50for aquatic algae is ca. 40µg/L (worst case consideration).