Vol. 24, No. 1
from Pure and Applied Chemistry
and Degradability of Organic Compounds in Air, Soil, and Water Systems
( IUPAC Technical Report)
Sabljic and W. Peijnenburg
Pure and Applied Chemistry, Vol. 73, No. 8, pp. 1331-1348
of organic compounds in air, soil and water is the most important factor
for evaluating possible adverse effects to humans and the environment.
The primary degradation process in the troposphere is the reaction with
the hydroxyl radical. For water and soil compartments, the primary degradation
process is biodegradation.
of this report are (i) to review published models and their evaluation
studies, (ii) to perform an in-house evaluation of general models for
estimating tropospheric degradation and biodegradation of organic compounds,
and (iii) to recommend reliable procedures for estimating degradability
of organic compounds in the environment.
evaluation procedure has shown that the most accurate method for estimating
tropospheric degradation is Atkinson's group contribution method.
Although this method has some limitations, it seems to be the method
of choice. A viable alternative to Atkinson's method is a direct calculation,
performed today almost routinely, of the reaction rate constants with
hydroxyl radicals. Recently, a methodology based on reliable semi-empirical
potential energy surfaces was developed that enables the calculation
of reaction rate constants within a factor of 2 of their measured values.
A PLS model and a set of 7 biodegradation rules have been found to be
the most reliable in estimating complete biodegradation of organic compounds.
However, it is recommended to use all four evaluated methods to estimate
biodegradation in the environment. If their results agree, such estimates
are very reliable.