[[(phosphonomethyl)imino]bis[ethylenenitrilobis(methylene)]]tetrakisphosphonic acid, ammonium salt

Toxicity to terrestrial arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to non-target arthropods on natural substrate (NTA other than pollinators)

Data waiving:

other justification

Justification for data waiving:

other:

Additional information

DTPMP-xNH₄ will dissociate into DTPMP and ammonia when it is released into soils where water is present. DTPMP and ammonia will therefore be treated separately for the purposes of deriving PNECs for soils.

DTPMP:

In accordance with Column 2 of REACH Annex IX, there is no need to further investigate the effects of this substance in terrestrial toxicity to arthropods studies because, as indicated in REACH guidance R7c Section R.7.11.6 (ECHA 2017), the quantitative chemical safety assessment (conducted according to Annex I of REACH) indicates that the Risk Characterisation Ratio is below 1, therefore the risk is already adequately controlled and further testing is not justifiable.   The substance is involatile and highly adsorbing and low toxicity was observed in short and long-term aquatic tests, and there is no reason to expect effects in the terrestrial compartment that were not expressed in the aquatic compartment.   Based on the long-term aquatic data set, the most sensitive trophic level is algae. Due to its high adsorption and low toxicity to aquatic organisms, DTPMP was assigned to soil hazard category 3 (R.7c Section R.7.11.6, ECHA 2017) and a screening assessment was conducted, based on the equilibrium partitioning method (PEC * 10 / PNECscreen). Testing for toxicity to terrestrial organisms has been carried out with one trophic level, earthworms (consumers). PNECsoil has been derived using both the equilibrium partitioning method and measured terrestrial ecotoxicity data and the most conservative value (PNECsoil based on measured terrestrial ecotoxicity data) has been used for PNECsoil. As the terrestrial RCRs based on this PNEC are < 1, no further toxicity testing of soil organisms is currently considered to be necessary.The phosphonate ligand binds strongly and irreversibly to various minerals present in soil and so bioavailability to soil organisms is extremely limited. Details on how the PNEC and the risk characterisation ratio have been derived can be found in IUCLID Section 6.0 and Chapters 9 and 10 of the Chemical Safety Report, respectively.

Ammonia:

As an inorganic ion, ammonium is ubiquitous in the environment, is not bioaccumulative and is highly water soluble. It is therefore not necessary to obtain test data for setting a PNECsoil for ammonia. Therefore the RCR has been based on DTPMP.