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a b s t r a c tIn the present work a small-scale terrestrial ecosystem (STEM) containing a soil collected from an agricultural field in Central Portugal was used to evaluate the effects of the combination of the herbicide glyphosate and the insecticide dimethoate. Earthworms (Eisenia andrei), isopods (Porcellionides pruinosus), turnip seeds (Brassica rapa), and bait-lamina strips were placed in the STEM. The results showed that the application of the recommended field dose of both pesticides did not cause any effect on the weight variation of earthworms and growth of the plants. The application of the herbicide, even at 5 and 10 times the field dose, increased feeding activity in soil (bait-lamina test), although the application of dimethoate led to a decrease in feeding activity in all concentrations tested. The binary mixtures performed showed that according to the Independent Action model, synergism (higher effect than expected from the single exposures) was observed in both the shoot length and fresh weight of B. rapa at 5 times the field dose, but antagonism was observed at 10 times the field dose. Regarding the germination success, synergism was observed at the field dose, but antagonism was detected at 5 times and 10 times the field dose. There was a decrease on the earthworm's weight in all concentrations tested, although no statistical differences were observed in any of the treatments made. Regarding depth distribution of E. andrei, worms were found in the upper layer more than it was predicted for all concentrations. In the mixtures with the field and 5 times the field dose there was a decrease in the feeding activity (bait-lamina consumption) by the soil fauna. From the four biomarkers assessed on the isopods (Catalase, Acetylcholinesterase, Glutathione-S-transferase, and Lipid peroxidation), only a significant decrease in the Acetylcholinesterase activity upon dimethoate and the binary mixtures exposures performed with the field dose was observed and on Lipid peroxidation at the field doses of single and binary exposures.

Terrestrial isopods from the species Porcellionides pruinosus were exposed to the maximum allowed nickel concentration in the Canadian framework guideline (50 mg Ni/kg soil) and to 5× this concentration (250 mg Ni/kg soil). The exposure lasted for 28 days and was followed by a recovery period of 14 days where organisms were changed to clean soil. Organisms were sampled after 24 h, 48 h, 96 h, 7 days, 14 days, 21 days, and 28 days of exposure, and at days 35 and 42 during the recovery period. For each sampling time the acetylcholinesterase (AChE), glutathione-S-transferases (GST), catalase (CAT), lactate dehydrogenase (LDH) activities were determined as well as lipid peroxidation rate (LPO) along with lipids, carbohydrates, proteins content, energy available (Ea), energy consumption (Ec) and cellular energy allocation (CEA). The integrated biomarker response (IBR) was calculated for each sampling time as well as for each one of the above parameters. In addition, mortality was also recorded throughout the assay. The results obtained showed that nickel induced oxidative stress, evidenced by results on GST, GPx, CAT or LPO, but also on changes in the energy reserves content of these organisms. In addition, this study showed that these organisms possess a specific strategy to handle nickel toxicity. In this case, biomarkers were associated with costs in the energy budget, and the increase of energy reserves has a compensation for that cost.

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Soil ecosystems are nowadays exposed to several physical, chemical and biological stressors, which are directly or indirectly related to anthropogenic activities. This chapter covers how contaminants affect the soil ecosystem structure, changing soil functions and services. Soil ecosystem structure is constituted by dynamic interactive abiotic and biotic compartments, dependent on major key factors like water and light. By changing this balanced system, soil functions are also impaired as they are strictly dependent on this structure and biodiversity. Soil functions include carbon transformations, nutrient cycling, maintenance of the structure itself, and regulation of biological populations. Activities like mining, agriculture, forestry or waste disposal are often responsible for the unbalance of soil structure and functions, by jeopardizing majorly the functional biodiversity compartment of the ecosystem. Therefore, the provision of goods along with ecosystem services will be also affected. Valuing soil ecosystem services is a difficult task and often lacking at the policymaking level, as the costs of services losses can go unnoticed. Therefore new strategies should be implemented to bring the concepts of structure, functions, services and goods on board at the regulation level.