Application of biomarkers in Lumbricus terrestris for pollution soil monitoring

As recently recognised the measurement of biochemical and cellular responses to pollutants (i.e. biomarkers) on living organisms in the soil has become of major importance for the assessment of the quality of terrestrial ecosystems. The aim of the preset work was to analyze a suite of cellular and biochemical biomarkers suitable for assessing the pollutant induced stress syndrome in the earthworm Lumbricus terrestris chosen as soil bioindicator organism. Several biomarkers were studied: granulocyte morphometric alteration, lysosomal membrane stability, tissutal metallothionein concentration, acetylcholinesterase (AChE) activity, micronuclei frequencies. Biochemical and cellular responses were related to whole organism endpoints (grow and reproduction rates). The study was carried out in standardised laboratory conditions and further validated in field conditions. In the laboratory study earthworms were exposed to copper sulphate and methiocarb in the soil, as representative models of heavy metals and organic xenobiotics. In the field study L. terrestris specimens were sampled in four sites in the Salento Peninsula (South of Italy) exposed to different anthropogenic impacts. The cellular and molecular biomarkers showed significant changes in response to both contaminant exposures. They corresponded to alteration in whole organism endpoints such as individual grow and reproduction rates and proved to be suitable for assessing stress syndrome in the field exposure experiment. In particular morphometric alterations of granulocytes proved to be a suitable biomarker of pollutant effect to be included in a multibiomarker strategy. It provides a sensitive generalized response to pollutants that can integrate the combined effect of multiple contaminants present in the soil.