Site-Specific Ecological Risk Assessment - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 709

all data, an interdisciplinary weighting over all three lines of evidence has to be
applied, which has serious disadvantages. It may be argued that as well the inte-
gration within (intra) and between (inter) the various lines of evidence in principle
concerns 'comparing apples and oranges'. However, for the moment it is the best
approach available, although it is still open for improvement and adjustment.
The first integration process, i.e. within one line of evidence, aims to get a
sufficient and complete set of information for estimating the risk from soil contami-
nation. Different pieces of information are used for this evaluation. For instance, the
application of Species Sensitivity Distributions (SSD) adopts the reasoning that all
organisms are equally important, although they have a different sensitivity towards
the contaminants at the site (Posthuma et al. 2002 ). Furthermore, estimates of effects
based on contrasting exposure scenarios, like pore water and food exposure, may be
used together to account for species-specific differences in bioavailability.

Table 15.2 Example on how to interpret the outcome of the integrated risk analyses of the Triad.
It is highly recommended that stakeholders and risk assessors produce such a table before the start
of the Triad process (reproduced with slight modifications from Jensen and Mesman 2006 )

Conclusion (land uses)

Deviation ( D ) Integrated risk (IR) Acceptable Not Acceptable

D <0.4 ∗ 0<IR<0.25 ∗ All land uses -

0.25 < IR < 0.50 A, R, I N, A (with ecological

and nature targets)

0.5 < IR < 0.75 I, (R) N, A, R (with

ecological and green
functions)

0.75 < IR < 1.0 I (only with

sealed soils)

N, A, R, I (with
ecological and green
functions)

D >0.4
further investigations or
(alternatively):

0 < IR < 0.25 A, R, I N, A (with ecological

and nature targets)

0.25 < IR < 0.50 I, (R) N, A, R (with

ecological and green
functions)

0.5 < IR < 1 I (only with

sealed soils)

N, A, R, I (with
ecological and green
functions)

∗ These numbers are arbitrarily chosen, and can be part of the negotiation process between stake-
holders, authorities and risk assessors. The goal of this table is to demonstrate the common sense
of choosing criteria for interpreting Triad results in the decision-making process.
D is a deviation factor indicating the level of disagreement between the lines of evidence of
the Triad ( D = 1.73 × standard deviation). IR is the integrated risk value from three different
lines of evidence (arithmetic mean). 'Not acceptable' land use does not necessarily have to imply
remediation or adapted soil management, but could also lead to more investigations. N nature, A
agricultural sites, R residential sites, I industrial sites.