Implementation of an active 'bryomonitoring' network for chemical status and temporal trend assessment under the Water Framework Directive in the Chiampo Valley's tannery district (NE Italy).

An innovative network based on transplanted bryophytes providing a continuous monitoring of the priority substances Cd, Hg, Ni, and Pb and other trace elements (Co, Cr, Cu, Fe, Mn, Zn) was designed for the watercourses flowing across an industrial district of NE Italy where both permitted and illegal wastes cause sporadic, intermittent or chronic events of environmental alteration. During a two-year preliminary survey, over 300 biomonitoring actions ('moss bag' transplantation and recovery) were successfully carried out at 25 stations: 190 of them occurred under acceptable conditions and provided results suitable for comparisons. Five environmental priorities were assessed and characterized in space and time. For these situations local authorities drafted a protocol for data management, to plan official controls and dissuasive actions. The 'moss bag' technique allows a flexible approach for both surveillance monitoring (trend assessment) and investigations (point source detection) in compliance with the Water Framework Directive 2000/60/EC as suggested by the recent Guidance Document on chemical monitoring of sediment and biota.