In-field and in-vitro study of the moss Leptodictyum riparium as bioindicator of toxic metal pollution in the aquatic environment: ultrastructural damage, oxidative stress and HSP70 induction.

This study evaluate the effects of freshwater toxic metal pollution in the highly contaminated Sarno River (South Italy), by using the aquatic moss L. riparium in bags at 3 representative sites of the river. Biological damage was assessed by studying metal bioaccumulation, ultrastructural changes, oxidative stress, as Reactive Oxygen Species (ROS) production and Glutathione S-transferase (GST ) activity, and Heat Shock Proteins 70 (HSP70) induction. The results showed that L. riparium is a valuable bioindicator for toxic metal pollution of water ecosystem, accumulating different quantities of toxic metals from the aquatic environment. Toxic metal pollution caused severe ultrastructural damages, such as the increase of ROS production and the induction of GST and HSP70s in the samples from the polluted sites. To assess the role and the effects of toxic metals on plants, L. riparium samples cultured in vitro were exposed to Cd, Cr, Cu, Fe, Ni, Pb, Zn at the same concentrations as measured at the 3 sites. Ultrastructural damages, ROS, GST, HSP70s were also severely affected by toxic metals. From our finding we can conclude that L. riparium can be proposed as a model organism in biomonitoring projects, and GST and HSP70s as promising biomarkers of metal toxicity.