Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Abiotic degradation

In general, phototransformation and hydrolysis are the main abiotic degradation pathways for a substance. Cu(II) IDHA is neither susceptible for phototransformation in air, water and soil nor for hydrolysis under environmental conditions. This is becauseCu(2Na)IDHA dissociates at neutral conditions as follows:

 

1. Cu(2Na)IDHA + H2O2 Na++ [CuIDHA]2-

 

The next step depends on pH and concentration of the substance:

2. Cu IDHA2- + H2O ↔  Cu2+ + OH-+ [IDHA]4 -→ Cu(OH)2 + [IDHA]4-

 

At neutral conditions, if the concentration of Cu(2Na)IDHA is high (the solubility is exceeded), Cu(OH)2precipitates. At acidic conditions, if the concentration of Cu(2Na)IDHA is low (the solubility level is not reached), precipitated Cu(OH)2 dissolves. The ligand could precipitate as H4 IDHA. However, neither strong acidic condition nor high concentrations of fertilizer (at the conditions of typical use of a fertilizer) are expected in the environment. Therefore, the second hydrolysation step can be ruled out under environmental conditions.   

In general, experimental investigations of abiotic degradation properties are not triggered for a registration under REACH.

Biotic degradation

Cu(II)IDHA was found to be inherently biodegradable (Adob, 2013). Based on the results of another study (Cokesa et al., 2004), it was shown that the substance is potentially biodegradable. By taking all relevant information from the conducted studies into account, it is concluded that the substance will be inherently biodegradable in the environment. Conclusively, the substance will be degraded when entering the environmental compartment and therefore will not be persistent.

Bioaccumulation

Bioaccumulation in aquatic organisms is not expected for Cu(II)IDHA. The first indication for that conclusion is given by the substance specific log Pow of -3.09 at 23 °C (equals Pow of ca. 0.001; experimentally determined; Stegient-Nowicka, 2011). Such a very low value indicates a lack of bioaccumulation potential. Bioaccumulation is expected for substances possessing a partition coefficient in the range of log Pow 4.5 to 6 according to ECHA Guidance R.11 (PBT Assessment, November 2014).

Transport and distribution

Soil adsorption is not expected for Cu(II)IDHA based on the intrinsic physico-chemical properties, i.e. logPow of -3.09 (Stegient-Nowicka, 2011).

The QSAR prediction with KOCWIN v2.00 (logKoc = 1.257 L/kg as key value; Chemservice S.A., 2014a) reveals that the substance possesses no strong binding capacity towards soil.

Henry´s Law constant was manually calculated and amounts to 2.97 E-10 Pa*m3*mol-1 at 20 °C (Chemservice S.A., 2014b). This value, as well as the key value of the Koc determination, will be taken into account for the chemical safety assessment (CSA), i.e. PNECsediment and PNECsoil derivation via the equilibrium partitioning method (EPM).