Registration Dossier

Ecotoxicological information

Short-term toxicity to fish

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

A weight of evidence approach was used to cover this endpoint. Two studies were included. The study of Harris (2014a) yielded a 96-h LC50 for rainbow trout > 100% v/v saturated solution of zirconium sulfate. A study with the insoluble read across substance zirconium dioxide yielded a similar 96-h LC50 of > 100 mg/L for zebra fish (Bazzon, 2000).

Key value for chemical safety assessment

Additional information

Three studies were included to cover this endpoint.

The most recent study was performed with zirconium sulfate in rainbow trout (Harris, 2014a). A stirring experiment performed to obtain a 100% v/v saturated solution indicated that no dissolved zirconium concentrations above the LOQ of 20 µg Zr/L could be detected. In addition, in a 100% v/v saturated solution, no mortality of fish was observed after 96 h (range finder). Since a measurable amount of zirconium could not be obtained in solution, it was decided at the request of the sponsor not to conduct a final toxicity test for zirconium sulfate. Based on the results of the range finding study, the 96-h LC50 was concluded to be > 100% v/v saturated solution.

In the second study of Tarzwell and Henderson (1960) fathead minnow was tested in soft and hard water using zirconium sulfate tetrahydrate. A 96-h LC50 of 14 mg Zr/L in soft and 145 mg Zr/L in hard water was obtained. The results were not considered reliable because they were reported in a too concise way not allowing thorough evaluation. However, these results support the results obtained by the other two studies.

It was considered most useful to cover the endpoint using a weight of evidence approach including the study from Harris (2014a) for zirconium sulfate, as well as a study performed with zirconium dioxide, an insoluble zirconium compound (Bazzon, 2000). This is considered relevant because at environmentally relevant conditions, zirconium from zirconium sulfate disappears from the aqueous solution through precipitation (e.g., as zirconium dioxide, zirconium hydroxide, zirconium carbonate, zirconium phosphate, etc.). The study from Bazzon (2000) also yielded a 96-h LC50 of > 100 mg/L (based on nominal initially added zirconium dioxide) and confirms that the toxicity of the 'water soluble' zirconium sulfate and insoluble zirconium dioxide is very similar.