Hazard Assessment and Contaminated Sites - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 536

sufficient evidence of carcinogenicity in experimental animals and strong evidence
in exposed humans that the contaminant acts through a relevant mechanism of car-
cinogenesis” (Vainio et al. 1992 ). This aspect of the evaluation process will become
increasingly important as the understanding of mechanistic pathways improves;
great advances are being made, especially with the advent of sophisticated labo-
ratory molecular techniques. Essentially four descriptive dimensions of mechanistic
data are proposed:

• evidence of genotoxicity (i.e., structural change at the level of the gene);

•

evidence of effects on the expression of relevant genes (i.e., functional changes
at the intracellular level);

• evidence of relevant effects on cell behavior;

• evidence of time and dose relationships of carcinogenic effects and interactions

between contaminant (Fitzgerald 1993 , p. 51).

12.3.8 The Hazard Identification Report

The Hazard Assessment component is likely to be based on a number of
studies, conducted in different species within each toxicology study type e.g.,
acute, chronic, developmental, or reproductive toxicity. The toxicity studies [or
review(s)/monograph(s)] on which the Hazard Identification and assessment are
based should be clearly identified. The report must be transparent, accountable and
defensible

12.4 Hazard Identification-Epidemiology

12.4.1 Introduction

Epidemiology and toxicology are complementary in Risk Assessment.
Epidemiology is the direct human evidence component and, if based on sound epi-
demiological methods, can provide the most important evidence in characterising
risk.
Epidemiology is “the study of the occurrence and distribution and determinants
of health related states or events in specified populations, including the study of the
determinants influencing such states and the application of the study to the control
of health problems” (Porta 2008 ).
An excellent introductory text is:

Bonita R, Beaglehole, Kjellstrom T ( 2006 ). Basic epidemiology. 2nd edition. World Health
Organization, Geneva.
Epidemiological methods are used to investigate the cause of adverse human
health effects; the natural history of health conditions; the description of the health