Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Read-across approach

In the assessment of the environmental fate and pathways of zinc neodecanoate, a read-across approach from data for the metal cation and the organic anion is followed. This read-across strategy is based upon the assumption that upon release to the environment and dissolution in aqueous media, zinc neodecanoate will completely dissociate and only be present in its dissociated form, i.e. as zinc cation and neodecanoate anion.

Upon dissolution in water, it is indeed predicted that metal carboxylates dissociate completely into the metal cation and the organic anion at environmentally relevant conditions. No information is available on the stability constants of zinc neodecanoate, but predictions of stability of other zinc carboxylates (Zn propionate, Zn valerate, Zn isovalerate and Zn benzoate) in a standard ISO 6341 medium (2 mMCaCl2, 0.5 mM MgSO4, 0.77 mM NaHCO3 and 0.077 mM KCl, pH 6 and 8) clearly show that monodentate ligands such as carboxylic acids have no potential for complexing zinc ions in solution (Visual minteq. Version 3.0, update of 18 October 2012. http://www2.lwr.kth.se/English/OurSoftware/vminteq/index.html).

Upon dissolution and dissociation of zinc neodecanoate into Zn2+ and neodecanoate anion, both constituent ions will each show its proper (bio)degradation, bioaccumulation and partitioning behaviour in the environment, as reported for the corresponding metal ion and carboxylic acid (Zn2+ and neodecanoic acid). The environmental fate and behaviour for the metal and organic moieties is predicted to be clearly different from each other, resulting in a different relative distribution over the environmental compartments (water, air, sediment and soil).

The branching pattern of the neo-acids is not expected to have a substantial influence on the intrinsic ecotoxicological effects. A comparison of environmental fate and ecotoxicological properties for a wide range of neo-acids did not reveal consistent differences between neodecanoic acid and fatty acids, C9-13-neo (US EPA, April 2009; http://www.epa.gov/hpvis/rbp/Category_Neoacids%20C5-28_Web_April%202009.pdf).