Page 293 - Materials Chemistry, Second Edition

4.5 Impact Categories, Impact Indicators and Characterisation Factors 277

can be regarded as flows. 305) This model was the starting point for an expansion
into an European model ‘EUSES’ (European Union System for the Evaluation
of Substances) which can be purchased from the European Chemicals Bureau at
the Joint Research Centre, Ispra. In Guin´ ee et al. (1996b), eight solutions of the
flow/pulse problem are presented which come to the same conclusion. In the same
paper, equivalence factors for human toxicity for 94 chemicals are listed and a
strategy for deriving new not yet calculated substances is provided. Equivalence
factors for the HTP refer to the substance pDCB in the compartment air.
4.5.3.2.4 Harmonised LCIA Toxicity Model Analyses on the depth of detail which
could be obtained in LCIA (contrary to, e.g. chemical risk assessment) marked
the beginning of a more recent development of toxicity evaluation in LCA. 306) By
Hertwich, Pease and McKone (1998) simple methods (see Section 4.5.3.2.2) were
integrated into the analyses of toxicity potentials or -equivalents called toxicity-based-
scoring.For LCAa Human Toxicity Potential (HTP) according to logic of GWP and
similar LCIA-characterisation factors is recommended. It is however noted within
the model calculations that no quality criteria were developed for physical and
chemical parameters, which are generally measurable with larger accuracy than
toxicities. Even in Europe these requirements to data quality are only statutorily
regulated for ‘new substances’. 307) The situation is slowly improving due to the
European Community Regulation on chemicals REACH (Registration, Evaluation,
Authorisation and Restriction of Chemical substances). But errors can still occur
becuse of missing or faulty substance data.
The simple toxicity evaluation according to Section 4.5.3.2.2 has not been further
developed, but the methodology outlined in Section 4.5.3.2.3 was elaborated. A
solution for multiple toxicity endpoints was shown by Hofstetter 308) the concept of a
‘disability adjusted lost life years (DALYs)’ elaborated on behalf of the WHO. 309) With
this concept and based on the assumption of a linear and cumulative dose-effect
relationship all partial effects are converted into an approximated ‘lost years of life’.
By conversion with fate and effect factors of inventory data as emitted pollutants
per functional unit this results to an (DALY/fU). The equations necessary are
principally the same as Equations 4.26 and 4.27. A quantitative and unambiguous

305) Heijungs (1995), Guin´ ee et al. (1996a,b) and Wegener Sleeswijk and Heijungs (1996). USES:
Uniform System for the Evaluation of Substances.
306) Hertwich, Pease and McKone (1998), Hertwich et al. (2001), Huijbregts et al. (2000b, 2005a),
Guin´ ee et al. (2002), Udo de Haes et al. (2002), Pant, Christensen and Pennington (2004)
and Molander et al. (2004) both in OMNITOX Special Issue, International Journal Life Cycle
Assessment Vol. 9, No. 5; Jolliet et al. (2003, 2004).
307) ‘New substances’ according to the European Union chemicals legislation are those which were
circulated after the taking effect of the chemical law (1981). A remaining of approx. 100 000
substances are called ‘Old substances’. This difference has now been removed within the new
European regulation REACH
308) Hofstetter (1998), WHO (1996) and M¨ uller-Wenk (2002a).
309) ‘Years of life lost’ by premature death due to illness per capita can be computed from statistics
and be calculated as an impairment of quality of life by diseases. This requires factors that were
determined by an international Panel. A factor scarcely below one means slight impairment, a
factor close to zero, very high impairment.