Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Hydrolysis:

Overall water DT50 has been determined (13 -24 days) and there are also data on oxidative degradation in water (catalyzed by divalent metal ions). It should be noted that these data do not strictly correspond to hydrolysis (reaction with water), but to oxidation (dissolved oxygen). However, they are much more relevant for risk assessment (incl. persistence assessment) than simple hydrolysis as a function of pH (a test in which dissolved oxygen and metals do not have to be detailed). Hydrolysis testing as a function of pH would not give any useful data for classification either.

Oxidative degradation:

MMH can be oxidized by dissolved oxygen in water, depending on pH and metals (e.g. Cu2+: catalyst). The suspected degradation products are hydrazine (itself very reactive: probably not a final product) and formaldehyde.

Haun et al (see acute inhalation toxicity data) mention similar oxidative degradation in air even in the small space of acute inhalation testing chambers:

"analytical studies were conducted to illuminate the mechanism of its disappearance in the exposure chamber. These studies, reported by Vernot et al, revealed that MMH underwent relatively rapid oxidation in air. This oxidation was catalyzed by a variety of materials, including some plastics and formulations of stainless steel. The primary end products of the oxidative reaction were molecular nitrogen and methane, although traces of other hydrocarbons and heterocyclic nitrogen compounds were observed.". In fact: "the major factor leading to the disappearance of MMH from the chamber was relative humidity."

Photostability:

The UV spectrum of the substance shows an absence of absorption in the UV wavelengths. Therefore no photodegradation in any media (air, soild, water) is anticipated.