Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Short-term toxicity to fish:

Based on read across from zirconium dioxide, another insoluble zirconium compound, zirconium basic sulfate is not expected to cause adverse effects in fish at the limit loading rate of 100 mg/L.

Short-term toxicity to aquatic invertebrates:

Based on read across from zirconium dioxide and zirconium basic carbonate, two other insoluble zirconium compounds, zirconium basic sulfate is not expected to cause adverse effects in fish at the limit loading rate of 100 mg/L.

Long-term toxicity to fish and aquatic invertebrates:

As zirconium basic sulfate is not classified for any endpoint, exposure assessment and risk characterization according to REACH Annex I do not need to be conducted. In view of the lack of effects in the available acute aquatic toxicity tests (performed with other insoluble zirconium substances), the extremely low water solubility of the substance, and the known tendency of zirconium to form complexes with various ligands in the aqueous environment (and thus to become completely non-bioavailable), there is no need to investigate further the effects on aquatic organisms. Based on this justification, these endpoints are waived.

Toxicity to aquatic algae and cyanobacteria:

In the absence of a study on zirconium basic sulfate itself a weight of evidence approach was proposed using two studies with other insoluble zirconium compounds (zirconium basic carbonate and a reaction mass of zirconium dioxide and cerium dioxide). In both studies, the observed growth inhibitory effects were attributed to phosphate depletion. Zirconium forms strong complexes with phosphate and therefore, when in excess, precipitates all phosphate from the test medium. No evidence has been found for direct toxic effects to occur to algae upon exposure to zirconium compounds. The phosphate depletion effect in limited systems such as used during aquatic ecotoxicity tests is not considered environmentally relevant and therefore the tested zirconium compounds, as well as zirconium basic sulfate, are not considered toxic to algae.

Toxicity to microorganisms:

No reliable studies were available for this endpoint.

Microorganisms in an STP will not be exposed to zirconium basic sulfate, as it will either be removed in the primary settling tank before reaching the microorganisms, or it will not be bioavailable due to complexation. In addition, testing is waived based on the following justification in accordance with REACH Annex VIII, 9.1.4 Column 2: the study does not need to be conducted if the substance is highly insoluble in water.