Human Health Risk Assessment - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 213

terms (risk is the multiplication of probability or chance, and effect) and the Hazard
Assessment (representing 'effect' in Risk Assessment terms). Basically, Human
Health Risk Assessment is all about linking exposure to effects. Issues that need
attention in the Risk-Characterisation phase are the combination of oral, inhalation
and dermal exposures, relevant timeframes for exposure in regard to the occur-
rence of effects, and the compatibility of Estimated Exposure and Critical Exposure
(as Toxicological Reference Value ). The Risk Characterisation is a crucial step in
Human Health Risk Assessment, since it results in a judgement about the contam-
inated status of the site in regard to human health, a widely accepted protection
target. Risk Characterisation is described in detail in Section 5.5.

5.2.3 Communication

Terminology in regard to human health risk appraisal can lead to an enormous
amount of confusion among the general public. Obviously, phrases such as 'poten-
tial exposure does not exceed the Toxicological Reference Value' overreach clear-
communication standards and often even arouse suspicion in the layman. The phrase
'there is no risk for human health', when respecting the basic principles of Risk
Assessment, may be used only in case of the absolute absence of any soil contam-
inants. On the other hand, the presence of a risk for human health, even when it
is an acceptable risk without any further consequences and/or actions required, if
not properly conveyed, might be translated into 'a bad situation that they (the reg-
ulators) are trying to mask', when the meaning of this risk is not communicated
clearly.
Scientifically, the phrase tolerable human health risk is often used. It repre-
sents an objective level of risk. Politically, the preferred phrase is acceptable human
health risk . It represents the politically acceptable level of risk, usually chosen on
the basis of scientific information about the range of risk levels. For simple commu-
nication purposes the word safe may be used, although it must be noted that this is
a subjective term.

5.3 Exposure Assessment

5.3.1 Definition

In popular terms, exposure is the amount of a contaminant that enters the
human body, expressed as contaminant mass, per unit of body weight and time
(mg.kg bw − 1 d − 1 ). The more formal IPCS (International Programme on Chemical

Safety) definition is: the concentration or amount of a particular agent that reaches
the body in a specific frequency for a defined duration (International Programme on
Chemical Safety 1999 , 2004 ). This definition implies that exposure could represent
a rate, expressed as mass per unit of body weight and time (mg.kg bw − 1

·

d − 1 ), but ·