Introduction to Contaminated Site Management - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 60

carbon fraction-based partition coefficient), for Human Health and Ecological Risk
Assessment applied to the same site. Moreover, as a third argument, it is wise
to focus on the same degree of conservatism/precaution in a Human Health and
Ecological Risk Assessment for the same site.
Actually, there is an important fourth reason for the integration of Human Health
and Ecological Risk Assessment, and that is to improve the balance in terms of
politically defined risk levels. The basic idea of the more integrated Risk Assessment
framework proposed by the WHO ( 2001 ) is to treat the relationships among Risk
Assessment, Risk Management, stakeholder input, and data-collection activities in
a general, parallel and concurrent way.
1.7.13 Harmonisation of Risk Assessment Tools
Since the beginning of risk-based contaminated site management in the early 1980s,
a large number of Risk Assessment tools have been developed in many countries.
As a consequence, many Risk Assessment tools exist for the same purpose. By
'Risk Assessment tool' is meant a model, regression equation, table, protocol,
graph or document, which can be used to determine variables that are used in Risk
Assessment. These variables can vary from a 'supportive' parameter such as a Kow
(octanol water partition coefficient), via the available fraction of an organic contam-
inant with regard to Ecological Risk Assessment, on up to 'direct' input parameters
such as measured concentrations in body fluids or tissue.
Although the development of Risk Assessment tools was often based on studying
existing Risk Assessment tools, the diversity of tools that are available world-
wide for the same purpose is remarkable. This diversity is partly due to different
geographical, cultural and social conditions, and sometimes due to differences
in political points of view. However, lack of scientific consensus also explains
many of the differences. An example of different Risk Assessment tools that serve
the same purpose is the procedure to determine concentrations in vegetables for
metals (essential for the calculation of exposure due to vegetable consumption).
Many countries that have a procedure on contaminated site management derived
BCFs (BioConcentration Factors) or regression equations for this purpose. In
some Northern European countries, BCF values were adopted from other Northern
European countries, but this is an exception rather than the rule. One reason that
many countries derived their own Risk Assessment tools might have to do with the
fact that the type of vegetables, and the specific genotype of that vegetable, that
grow in different countries (and certainly in other climate zones) differs. This is
a geographical difference. Another reason is that in different countries, apart from
the possibilities of growing specific crops, different type of vegetables are grown
because of cultural differences or traditions. However, there is no scientific, gen-
erally accepted protocol that is used in these countries with regard to the amount
of data for each vegetable, quality of the data set, extrapolation margins outside
the range of the input data, etc. In Europe, one of the major challenges in Risk