Introduction to Ecological Risk Assessment - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 575

13.1 Introduction

13.1.1 Vital Soil

The biggest mistake that could be made regarding the vitality of soil is to consider it
as 'dead material'. Slightly more realistic, many people believe that soil is inhabited
by only a handful of organisms that they can see with the naked eye, mainly moles,
earthworms and maybe 'some obscure beetles'. In reality, soil is the habitat of an
enormous number of organisms. In fact, the topsoil is the part of the earth with the
highest Biodiversity (Takeda et al. 2007 ), which includes more than one fourth of all
living species on earth (European Commission DG ENV, 2010 ). It is buzzing under
our feet even if most of us ignore it. According to the Encyclopaedia Britannica
one square meter of rich soil can harbour as many as 1,000,000,000 organisms.
Thus, most of the people that are not directly involved in soil biology or ecology are
impressed when they learn about the huge number of species and organisms in soil.
They are even more impressed when they find out what important functions the soil
ecosystem performs and when they are confronted with the complexity of the way
organisms are performing these functions. Just the partition between the different
types of organisms and the succession of tasks performed by them surpasses the
human imagination.
It is generally acknowledged that the strain on the environment, and on the soil
ecosystems, is enormous. In many countries protection of the soil ecology is the sec-
ond most important protection target in dealing with contaminated sites after human
health protection. However, since the very beginning of soil policy in the late 1970s
only a few countries have given the same weight to ecological soil protection as to
human health protection. The countries that have ecological protection included in
their soil policies often claim that both human health and ecology deserve uncondi-
tional protection in a civilized society. Appreciation of soil ecology rests on the two
following basic principles which are closely interrelated:

• The optimisation of biodiversity : the most basic principle, on which the appre-

ciation of the soil ecosystem is based, is the protection of living beings (soil
organisms), because of their intrinsic value and independent of their possible use.

•

The so-called Ecosystem Services , these are the processes performed by organ-
isms within ecosystems, processes that are essential for the survival of mankind.
This relates to the role of soil organisms in profitable functions such as the growth
of plants and trees, the degradation of organic matter, the purification of soil
from contaminants, the protection of groundwater quality, and the role played in
the structure formation of soil that is important, for example, for agriculture and
water regulation. All these processes are indispensable for agriculture and nature
and, hence, essential for the quality of human life.

The subject of Ecosystem Services is far less known to the public than the subject
of Biodiversity and, hence, almost exclusively appreciated (but highly appreciated!)
by biological and ecological experts and other insiders. Recently these Ecosystem
Services have received explicit attention in the EU Soil Thematic Strategy. Another