ACTIVATING THE GLUTATHIONE SYSTEM OF EISENIA FETIDA DURING EXPOSURE TO CONTAMINATED SILT SLUDGE

Abstract

In order to identify effective and inexpensive method of purifying wastewater sludge, we tested the hypothesis about the ability of earthworm Eisenia fetida to detoxify the silt complex of different chemical components through the activation of glutathione system. In the laboratory conditions, earthworms were exposed to silt from the sedimentation tanks during 112 days in the boxes, while the control earthworms were on a sunflower husk substrate. Glutathione S-transferase (GST) activity and reduced glutathione (GSH) content in coelomic fluid of earthworms were measured spectrophotometrically. The results revealed biomass of the experimental E. fetida worms was declined by 69% compared to control after the exposure. Heavy metals content in the silt decreased in the range from 13% (for zinc and lead) to almost 100% in the case of cadmium compared to beginning of the experiment. The GST activity increased significantly (87% above the control level), as well as GSH content (36% above the control). Induction of 4 new proteins biosynthesis was found by gel-electrophoresis exploration of coelomic fluid proteins of the worms exposed to contaminated silt. Study results indicate a high level of toxicant-induced activation of the earthworm glutathione-dependent system, and confirmed the efficiency of E. fetida using for detoxification of silt from the sedimentation tanks in the case of complex contamination.