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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Description of key information

LC50 earthworms > 1000 mg/Kg ww
NOEC earthworms > 1000 mg/Kg soil dw

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

The study 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.

The possible effects of Potassium phosphonate (KH2PO3/K2HPO3) on earthworm (Eisenia fetida) were determined in a 14‑days artificial soil study according to the OECD Guideline 207.

Adult earthworms were exposed under defined conditions to artificial soil containingpotassium phosphonateat five concentrations in a geometric series, namely 9.5, 30.5, 97.7, 312.5, 1000.0 mg/kg (dry weight), additionally an artificial soil without test item was tested as negative control.

The exposed organisms were checked for mortality 7 and 14 days after test initiation and for weight change at the end of the test (14 days).

At the test start mean moisture content of the soil was 36.3 % while at the end of the test the mean water content was 33.6 % (measured mean value in negative control and treated soils).

The pH value of artificial soil at the test start was 6.34 for the negative control and ranged between 6.05 – 6.37 for the treated soil. At the end of the test the pH wasthe negative control and ranged between 6.92 - 7.17 for the treated soil.

Temperature ranged between 18.2 °C – 20.7 °C during the test period while light intensity (measured daily) ranged between 631 – 796 Lux.

In the control 0 % mortality was observed after 7 days and after 14 days, which complies with the validity criterion of the test, allowing a maximum mortality of 10 % in the negative control at the end of the test. The obtained experimental results therefore allowed for the determination of valid endpoints, i.e. mortality and the sublethal effect, body weight change. No exterior or behavioural abnormalities in both control and treated earthworms were detected during the test.

Concerning mortality, the LC0, LC100, LC50, the NOEC and the LOEC values at 7 and 14 days were assessed and the LC50 resulted > 1000 mg/Kg d.w.

Concerning the sublethal endpoint weight change, no significant decrease of earthworm’s body weight was shown at any tested concentration at the end of test.

NOEC and LOEC values for this sublethal effect at the end of the test, expressed in terms of of active ingredient concentrations are > 1000 mg/kg d.w. respectively.

The acute toxicity of test item of Potassium phosphonate (KH2PO3/K2HPO3) was tested on earthworms Eisenia fetida in a full test and all endpoints, the LC0, LC100, LC50, the NOEC and the LOEC values at 7 and 14 days, were assessed as equal to or greater than 1000 mg/Kg d. w., for both mortality and change in body weight.