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Environmental fate & pathways

Biodegradation in soil

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Description of key information

A relatively low level of biodegradation in soil was achieved in a test using the parent acid (ATMP, CAS 6419-19-8). 

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Additional information

Two reliable studies, measured with the parent acid (ATMP, CAS 6419-19-8), are available. A soil biodegradation rate of 14% over 148d in a silt loam soil was determined (Saeger 1978). Soil biodegradation rates of between 7 and 15% over 199d in four soils were determined (Saeger 1979).

This substance is a member of a category of various ionised forms of the acid ATMP (CAS 6419-19-8). The main assumption is that ammonium is not significant in respect of all the properties under consideration. In dilute aqueous conditions of defined pH a phosphonate ion will behave no differently to the parent acid, at identical concentration of the particular speciated form present and will be fully dissociated. Hence some properties (measured or expressed in aqueous media, e.g. ecotoxicity) for a salt can be directly read across (with suitable mass correction) to the parent acid and vice versa. Exposure of the soil would only be expected to occur via some form of aqueous processing (e.g. from spreading of WWTP sewage sludge). Thus it is acceptable to additionally read across between the parent acid and salts for the soil compartment. In the present context the effect of the counter-ion (potassium) will not be significant. In biological systems and the environment, polyvalent metal ions will be present, and the phosphonate ions show very strong affinity to them.

The ammonium ion upon release into the environment would enter natural nitrogen cycles in air, soil and water.