Although no all end-points were unanimous, especially the enzymatic
ones,we can highlight a rather clear picture of the biofiltration effect.
In fact, zebra mussels seem to be able to greatly reduce the acute
toxicity, as shown by the mussel mortality decrease mainly in the 50%
IN mixture and the corresponding significant raise of hemocytes' viability
after the wastewaters' recirculation for 4 and 24 h. More difficult is
the explanation of trends described by biomarkers measuring chronic
effects, since some of them confirmed a possible gain in the mussels'
health status, but many others did not respond to the biofiltration treatment.
In detail, NRRA, LPO and PCC appeared to be influenced by the
biofiltration and tend to decrease the negative effect produced by
wastewater mixtures, while no evident variations were noticed for antioxidant
enzymes and biomarkers of genotoxicity. Thus, the high mortality
is probably not caused by an increase of oxidative stress and
genetic injuries, but maybe to the blocking of other physiological
pathways or to mechanical damage originated by an excess of SPM
that occludes gills. In this case, the main action of the biofiltration
made by D. polymorpha specimens can be thewastewaters' clarification
through the abatement of SPM by the production of faeces and
pseudofaeceswith also the related chemical compounds bound to them.
Although no all end-points were unanimous, especially the enzymaticones,we can highlight a rather clear picture of the biofiltration effect.In fact, zebra mussels seem to be able to greatly reduce the acutetoxicity, as shown by the mussel mortality decrease mainly in the 50%IN mixture and the corresponding significant raise of hemocytes' viabilityafter the wastewaters' recirculation for 4 and 24 h. More difficult isthe explanation of trends described by biomarkers measuring chroniceffects, since some of them confirmed a possible gain in the mussels'health status, but many others did not respond to the biofiltration treatment.In detail, NRRA, LPO and PCC appeared to be influenced by thebiofiltration and tend to decrease the negative effect produced bywastewater mixtures, while no evident variations were noticed for antioxidantenzymes and biomarkers of genotoxicity. Thus, the high mortalityis probably not caused by an increase of oxidative stress andgenetic injuries, but maybe to the blocking of other physiologicalpathways or to mechanical damage originated by an excess of SPMthat occludes gills. In this case, the main action of the biofiltrationmade by D. polymorpha specimens can be thewastewaters' clarificationthrough the abatement of SPM by the production of faeces andpseudofaeceswith also the related chemical compounds bound to them.
การแปล กรุณารอสักครู่..