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Environmental fate & pathways

Hydrolysis

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Description of key information

ATMP and its salts are not hydrolytically unstable under ambient conditions.

Key value for chemical safety assessment

Additional information

The requirement to test the substance for hydrolysis was waived as the substance is not susceptible to hydrolytic degradation.

This is supported by results from dark and sterile controls from several types of degradation study, in which no degradation (as production of orthophosphate) was observed over time periods of up to 60 days under ambient conditions in water. There is evidence (reliability 4) that partial breakdown (removal of one chain from the N atom, replaced by H) occurs, at a rate of 40% over 4 days (Steber and Wierich, 1987).

Schowanek and Verstraete (1991) report abiotic degradation half-lives of the order of 30 days in the presence of calcium, magnesium and iron divalent ions. Nowack (2003) remarks that degradation of amine-containing phosphonates is negligible in metal ion-free oxygenated solutions; the presence of metal ions increases the rate of degradation to approximately 1% per day. The degradation is also negligible in the absence of dissolved oxygen indicating that redox reactions play a role. The half-life for the reaction of ATMP in the presence of equimolar Mn(II) and in equilibrium with 0.21 atm O2 was 10 min at pH 6.5. The reaction occurs more slowly under more alkaline or acidic conditions.