**5. Conclusions**

Natural soil resources must be interpreted and studied by taking into account all their compartments, since they act together in different soil functions.

Contaminated soils have been largely monitored through physical-chemical analyses. However, soil quality assessments and synergistic effects caused by contaminants are not taken into account. Ecotoxicological tests are critical for the evaluation of potential environmental risks posed by these contaminants.

It is important carrying out tests by using organisms that represent terrestrial ecosystems in toxicological evaluations. Toxicity tests are tools that help the management of contaminated areas. They indicate the viability of natural environmental recovery, since organisms in the field degrade and mineralize substances in contaminated environments.

It is recommended to extend the present study to other organisms, such as microcrustaceans, living in different habitat types (sediments and water) in order to cover different trophic levels and to assess whether there is, or not, toxicity transfer between food chain levels.
