Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

The biodegradation of TOPP as a whole substance is required for the purposes of hazard classification. However, for the purpose of environmental exposure assessment and persistence assessment, it is necessary to consider the properties of the individual constituents present in the substance. As a consequence, in this section, data describing the biodegradation of the whole substance and its constituents are considered. The constituents of TOPP are naturally-occuring terpenes that are components of trees and shrubs. It is therefore, expected that biodegradation will be a significant removal process in the environment.

Additional information

For the purposes of environmental exposure assessment and persistence assessment, a biodegradation rating is assigned to each constituent block on the basis of BIOWIN scores for individual constituents. As far as possible, the constituents allocated to each hydrocarbon block had the same BIOWIN-based biodegradation rating. The overall degradation rating for the block was assigned on a case-by-case basis, taking into account the rating for the most abundant constituent(s) in the block.

Additional information on the biodegradation class from available measured data for the constituents of TOPP has been presented. Where measured data indicate a different class for biodegradation compared to the prediction, this measured biodegradation rating is used in preference to the predicted rating.

Biodegradation rates in water, sediment and soil compartments are predicted within EUSES 2.1.2, based on ready biodegradability ratings. However, a maximum half-life of 300 days in soil and sediment were set where the predicted half-life is greater than 300 days. This is due to the naturally occuring nature of the constituents of TOPP and their ability to be metabolised by microorganisms.