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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic plants other than algae

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Administrative data

Link to relevant study record(s)

Description of key information

Chlorine dioxide reacts rapidly degrading to chlorite which also degrades rapidly and chlorate as dominant species. No data are available for the two more ephemeral substances. However, a long term plant study is available for chlorate. The NOEC for all endpoints was 10 mg/L for sodium chlorate, i.e. 7.84 mg/L as Chlorate.

Key value for chemical safety assessment

Additional information

According to the REACH Guidance, an aquatic plant toxicity study might be required if exposure is possible. The direct exposure of non-target aquatic plants to chlorine dioxide is highly unlikely from use in the supported product types. Therefore, an aquatic plant toxicity study is not required to assess chlorine dioxide effects.

Chlorine dioxide react easily and rapidly generating chlorite and chlorate as dominant species. In the absence of oxidisable substances, and in the presence of pH > 9, chlorine dioxide dissolves in water and decomposes with the slow formation of chlorite and chlorate ions.

No key studies valid were found in Sodium chlorite for aquatic plants other than algae. One toxicity study valid was used for Sodium chlorate on an aquatic plant, Lemna minor (Scheerbaum 2003, according to OECD guideline 221), the EC50, LOEC and NOEC after 7 days of exposure were 134 mg/L, 32 mg/L and 10 mg/L of Sodium chlorate, respectively.

However, we cannot compare and conclude these results with data on chloride dioxide.