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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Reference
Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Type of information:
experimental study planned (based on read-across)
Study period:
The Registrant intends to review the testing strategy and the test material in accordance with the timings and reasoning proposed in the response to the ECHA communications TPE-D-2114422735-50-01 and TPE-D-2114422736-48-01 (attached in IUCLID Section 13).
Justification for type of information:
Read-across between ATMP salts and the parent acid substance is considered appropriate because:
The category hypothesis is that all the members are various ionised forms of the acid CAS 6419-19-8. In dilute aqueous conditions of defined pH, a salt will behave no differently to the parent acid, at identical concentration of the particular speciated form present, and will be fully dissociated. Hence some properties (measured or expressed in aqueous media, e.g. ecotoxicity) for a salt can be directly read across (with suitable mass correction, see Section 1.4 of the CSR) to the parent acid and vice versa. In the present context the effect of the sodium and potassium counter-ions will not be significant. The ammonium salt does present a particular issue since ammonia drives the toxicity of the substance and will be assessed separately.
The behaviour of phosphonates in the environment will be profoundly affected by their concentration in water, the concentration and identities of metal ions, and the solids content per unit volume of water. From surface water through to soil a wide range of these parameters will be exhibited. Very few data concerning background concentrations of phosphonates in the environment are published, possibly due to the difficulties in detecting these substances at low concentrations in environmental media. Almost all natural waters contain more ions than the usual PEC values of the phosphonates.
In addition, in the environment the salt form is immaterial and speciation will occur in natural media. Similarly, all environmental related endpoints, use of buffered test media results often reflect a salt speciation relevant for ~pH7 only and it would be impossible to test specific salts associated with high and low pH. Detaching or attracting a proton does not change the chemical safety assessment of the molecule as long as no other part of the molecular skeleton is changed, because in studies or when there is exposure, the pH will control the identity of the form or forms present.
Therefore, it is considered appropriate to read-across between the ATMP category members and attribute the effects to the acid component of the phosphonate.
Qualifier:
according to guideline
Guideline:
OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei))
Specific details on test material used for the study:
The test material will be a sodium salt of ATMP in the neutral pH range. However, the Registrant intends to review the testing strategy and the test material in accordance with the timings and reasoning proposed in the response to the ECHA communications TPE-D-2114422735-50-01 and TPE-D-2114422736-48-01 (attached in IUCLID Section 13).
Test organisms (species):
Eisenia fetida

Description of key information

Key value for chemical safety assessment

Additional information

No reliable toxicity data are currently available for soil macroorganisms except arthropods. A PNECsoil can, however, be calculated from the PNECaquatic by the equilibrium partitioning method and a confirmatory OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei)) long-term toxicity to terrestrial organisms test has been proposed for the ATMP category, provisionally. The Registrant intends to review the testing strategy and the test material in accordance with the timings and reasoning proposed in the response to the ECHA communications TPE-D-2114422735-50-01 and TPE-D-2114422736-48-01 (attached in IUCLID Section 13).