EU-SICHERHEITSDATENBLATT Dieselkraftstoff ... - Schmierstoffe

probabilities are adjusted to best reproduce documented degradation pathways for over
500 chemicals. The model predicts biodegradation pathways and primary/ultimate halflives
as well as the simulation of integral biodegradation data, such as BOD, CO2
production and the level of the different metabolites. This model (and others) are further
discussed in the next section here the models for addressing the metabolites are
described.
1.2 Predicting the PBT properties of metabolites compared to parent
compounds
To do this assessment a series of molecules were assessed using the OASIS Laboratory of
the Mathematical Chemistry models (LMC). These are described below.
1.2.1 OASIS LMC models: Environmental fate and Ecotoxicity
1.2.1.1. Catalogic BOD model (OECD 301 C)
This is based on an expert system in which predicted biotransformation pathways are
combined with a probabilistic model that calculates the probabilities of individual
transformations. The principal catabolic steps are derived from a set of metabolic
pathways predicted for each chemical from the training set, 1078 chemicals of MITI I
(OECD 301 C) database were used as a training set. The output is given as percentage of
the theoretical biochemical oxygen demand (Jaworska et al., 2002). The system predicts
the catabolic pathways, the level of stable metabolites and their physical-chemical and
toxic endpoint values. The primary and ultimate half-lives are calculated.
1.2.1.2. Catalogic BOD model (OECD 301 F)
The model predicts the integral biodegradation estimates as BOD and CO2 production for
OECD 301F protocol by simulating the metabolic pathways. Primary and ultimate halflives
are predicted. The magnitudes of metabolites as well as BOD are defined as a
function of time. The model is based on a training set with 488 kinetic biodegradation
curves provided by industry (e.g. BASF, ExxonMobil, Givaudan, Dow Chemical).
1.2.1.3. BCF Base Line Model
A refined BCF Base Line Model is used to predict bioaccumulation potential of the tested
chemicals. The maximum bioaccumulation (i.e., highest log BCF) for a given
lipophilicity (i.e., log Kow value) is exhibited by chemicals ignoring their bioavailability
and metabolism. The maximum potential for bioconcentration is further reduced by
different factors: organism dependent (like metabolism) and chemical properties
dependent like molecular size, ionization, water solubility and others). Metabolism,
molecular size, ionization and water solubility are accounted explicitly in the model as
used.
The training set of the model contains 706 chemicals covering variety of chemical
classes: alkanes, alkenes, mono- and di- aromatic hydrocarbons, polycyclic aromatic
hydrocarbons, polychlorinated dibenzo-furans, polychlorinated dibenzodioxins,
polychlorinated biphenyls, cycloalkanes and cycloalkenes, chloroaromatic chemicals,
perfluorinated acids, chlorinated biphenyl ethers, aliphatic esters, and chloroorganic
chemicals (Dimitrov et al. 2005a, 2005b and 2007).
111