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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Description of key information

As there is no data available for tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate, results of the parent acid, 2-phosphonobutane-1,2,4-tricarboxylic acid are taken into account for this endpoint.
2-Phosphonobutane-1,2,4-tricarboxylic acid, was tested for toxicity of earthworms according to OECD Guideline 207. After 14 days of exposure, no significant difference was observed in mortality rate and in weight in any of the different concentration groups that were examined.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:
1 000 mg/kg soil dw
Long-term EC10, LC10 or NOEC for soil macroorganisms:
1 000 mg/kg soil dw

Additional information

As there is no data available for tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate ("PBTCNa4") a read-across approach with the corresponding parent acid 2-phosphonobutane-1,2,4-tricarboxylic acid ("PBTC") is proposed.

In aqueous media, PBTCNa4 and PBTC dissociate into the corresponding anion (2-phosphonatobutane-tricarboxylate ion) and the sodium ion and hydrogen ion (proton), respectively. Fate, behavior and the ecotoxicological properties of PBTC and its tetrasodium salt are thought to be an effect of the phosphonato-carboxylate ion rather than of the sodium ion or the hydrogen ion (proton), which are normal constituents in environmental systems and have no relevant ecotoxic properties in low concentrations.

Therefore a read-across between PBTCNa4 and PBTC acid is justified.

Different concentrations (1 -1000 mg) of PBTC, thoroughly mixed in artificial soil, were tested for toxicity of earthworms according to OECD Guideline 207. After 14 days of exposure to the test material, no significant difference was observed in mortality rate and in weight in any of the different concentration groups that were examined compare to the control group. In addition, abnormalities, like changes in behaviour were also not observed in the study. Thereby, the LC50 (14 days) was determined for the substance as > 1000 mg/kg dry weight substrate. In relation to weight alteration and symptoms, the no-observed-effect concentration (NOEC) was 1000 mg/kg dry weight substrate, the lowest-observed-effect concentration (LOEC) and the lowest tested concentration with mortality (LLC) was > 1000 mg/kg dry weight substrate.