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Environmental fate & pathways

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The environmental fate properties of the triphenyl phosphite (TPP) and related phenyl/alkyl phosphites generally include: low water solubility, low vapor pressure, and rapid hydrolysis to phosphorous acid and corresponding alcohols (in the case of TPP it is phenol).

In fugacity Level III modeling with equal emissions to all three compartments or with just emissions to water, the majority of the category members partition to the soil and sediment. With emissions to just air or soil, the majority of the releases partition to the soil compartment. 

A recent OECD 301D biodegradation study on TPP (van Ginkel, 2015) showed that this substance does readily biodegrade. The 28 -day degradation of TPP in this study was 84%. These results are also consistent with the expectation that TPP rapidly hydrolyzes to phenol, which is also readily biodegradable. The earlier TPP biodegradation study is now considered invalid as it appears that the study did not adequately address the very low water solubility of this substance. The new data demonstrate that TPP is not persistent.

Reliable bioaccumulation concentration factor (BCF) estimates for TPP are difficult to obtain due to the rapid hydrolysis. However, it is because of this rapid hydrolysis that the potential for bioaccumulation is expected to be very low. BCF values from the BCFBAF v3.00 model are very low, though these data are not considered reliable because they do not consider hydrolysis or biotranformation of the substance, both of which are expected to be high. The BCF of phenol (the primary hydrolysis product) is 17.5 L/Kg (EU Phenol RAR 2006) and the other hydrolysis product is phosphorous acid, which is inorganic, has a BCF of 2.68 L/kg wet-wt (BCFBAF 3.01). These data support the conclusion that neither TPP nor its hydrolysis products are expected to bioaccumulate and do not meet the criteria for B or vB.