The presence of a pollutant in the soil does not entail a soil contamination. In fact, a little amount
of certain pollutants are present in practically every soil.

In order to establish that a soil is polluted the level of pollutants must reach certain values stated
by authorities or, anyway, they must involve an unacceptable risk for human health or ecosystems,
which is decided through risks assessment.

Risks assessment is a complex issue since it requires a detailed description of pollution focuses,
pollutants characteristics and its concentration in soil; a characterization of textural and physico-
chemical soil properties; a description of physical environment, pollutant means of transport,
potential receptors, ways of exposure to pollution and pollutant reference levels; a risk
quantification and, finally, an uncertainty analysis.

Liquen Consultoría Ambiental S.L. has broad experience in environmental studies and in the
integration of multidisciplinary information required by a reliable risk assessment.