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Ecotoxicological information

Endpoint summary

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Additional information

All studies reported are well conducted on the similar substance Reaction mass of dipotassium phosphonate and Phosphonic acid, potassium salt (1:1). Rationale for Read Across is attached at point 13.

Possible adverse effects of potassium phosphonate were determined in three terrestrial trophic levels at concentrations at or above the maximum application rate of potassium phosphonate onto soil when used as a fertiliser.

No adverse effects were determined in earthworms (OECD 207) at 1000 mg/kg soil (d.w.), nor in two terrestrial plant tests (OECD 208 and OECD 227) at the maximum application rate of 4 L/Ha, nor in two tests performed on soil microorganisms (OECD 216 and OECD 217) at the maximum application rate of 25 mg/L nor 5 times the maximum application rate.

The performed tests consist of short-term studies for earthworms and plants, while the tests on soil microorganisms are considered to determine long term effects.

Since no adverse effects were observed under the conditions of the performed OECD tests and taking into account the mode of action of potassium phosphonate when used as a plant protection product (i.e. fungicide) the NOEC based on the long term soil microorganism tests of 125 mg/kg soil could be chosen as the environmentally most relevant endpoint. Since multiple tests have been performed and since these tests determine both acute (earthworms and plants) and long term endpoints (soil microorganisms) an assessment factor of 100 is chosen for risk assessment purposes.

Despite the long-term value of 125 mg/kg soil, the most conservative value of PNEC used for the soil risk assessment has been derived from the EC50 on soil macroorganism earthworms.