contaminants significantly affected microbial community structure of earthworm faeces by
increasing G- bacteria, thus also increasing the bacteria/fungi ratio while decreasing the G+/G- bacteria
ratio. Such shift was also reflected on soil microbial community, thus suggesting a close relationship
between microbial community of soil and of earthworm faeces. Neither of the Co treatments affected soil
microbial basal respiration whereas they increased the microbial biomass specific respiration or
metabolic quotient, suggesting some stress induction on soil microorganisms. Earthworm health was
strongly affected as revealed by the reduced fluidity of fatty acids extracted from the body tissues. In
addition, the histological investigations, after the depuration period, showed positive results about the
NPs toxicity. In particular, TUNEL-positive nuclei in epidermis and in peritoneum, suggest the presence of
toxicosis.The ESEM-EDS technique revealed the presence of Ca-P spherules (calcification) between
mouth and clitellum of earthworms fed with Co2+ contaminated food