Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

General discussion of environmental fate and pathways:

Based on available data and described in the following sections, the environmental fate and pathways of DEHP can be summarized as follows:

As volatilization DEHP is very limited at ambient temperature, and half-life in the atmosphere is of 1 day due to phototransformation, DEHP may not contaminate the air compartment.

Being not soluble in water (3µg/L) the hydrolysis and photolysis of DEHP are not expected in water. With a high potential of adsorption (Log Kow = 7.5; Log Koa=10.5 and Koc estimated at 165,000) the equilibrium for DEHP is in favor of particles. Thus the transport of DEHP in aquatic environments will to a high degree depend on the transport of particles.

Therefore final compartments for DEHP are expected to be sediments and soils.

DEHP has been demonstrated to be readily biodegradable in water, fulfilling the 10-day window requirement. Considering the high adsorption of DEHP on particles and since sediment reaches low oxygen level, sediment is considered as the final compartment for DEHP in aquatic systems. This distribution is supported by the distribution modelling Mackay Level 1. Simulation studies on degradation in surface water, sediment and soil are available. Due to the very heterogeneous DT50 values obtained in these studies, conservative half-lives for these media are assumed:

         DT50 freshwater (12°C): 50 days

         DT50 bulk sediment (12°C): 300 days

         DT50 soil (12°C) 300 days

Based on a partition coefficient of 7.5, DEHP should be expected to be bioaccumulative in organisms. However, based on multiple bioaccumulation studies in aquatic systems, it appears that DEHP does not bioaccumulate and even shows food web biomagnifications factor below 1 indicating a trophic dilution. Moreover in terrestrial environment, DEHP is bioaccumulated neither by plants nor by soil organisms.