Health assessment of polluted soils after eisenia foetida ex situ bioassays based on conventional and in vitro cellular biomarkers and microarray technology

Resumen

Aimed to contribute to the development of cost-effective early warning tools to assess soil health, a suite of biomarkers and biological effect measurements has been applied together with chemical parameters in earthworms, Eisenia foetida, exposed to soils artificially contaminated with inorganic and organic pollutants as well as chronically contaminated real soils. In addition a diagnosis strategy for assessing soil ecosystem health on the basis of a three-tier approach (screening + scoring + understanding) based on ex situ exposed earthworms E. foetida has been designed and applied. The employed biomarkers largely reflected the existence of sublethal effects of Zn, Cu, Pb, Kerosene (Ke), Cd and Ke+Cd contaminated soils. Moreover, the combination of one experimental design of three days of duration exposing stocked E. foetida to a set of selected contaminants together with an implemented, rapid and sensitive Neutral Red Uptake test has been proved to be a cost-effective tool for screening the health status of soil contaminated by metallic and organic contaminants. Moreover, the simplicity, rapid performance and the possibility to deal with a high amount of different soils (high-throughput) result relevant for decision making in soil management. Finally, the pilot study for assessing soil ecosystem health in chronically polluted sites on the basis of a three-tier approach (screening + scoring + understanding) designed to be cost-effective and scientifically based, and to provide straightforward advice and support to managers and stakeholders involved in environmental protection was developed and applied on E. foetida exposed ex situ under laboratory conditions during 3, 10 and 17 days to soil samples collected in three different abandoned mining sites (previous exploitations of Fe, Zn and Pb) and a reference site in the Basque Country. Presently, soils were classified as harmful and others as unhealthy, not apparently unhealthy or healthy, and putative causative agents of the soil health affection, in agreement with supporting chemical data were identified.