Bryophytes as indicators of trace metals pollution in the River Brenta (NE Italy)

The performance of aquatic bryophytes for detecting metal pollution was tested along the River Brenta, in NE Italy. Nine sampling sites were selected, three of them along short tributaries with no anthropic influence upstream, the others along the main bed of the river. Two sites were deliberately placed downstream from a previously known pollution focus. The multivariate analysis (classification and ordination) of the matrix of 10 metals and 38 samples revealed: (i) a good discrimination between 'clean' and potentially polluted sites; (ii) two contamination syndromes, one by As and, to a lesser degree, Pb, and the other by Cr, due to agricultural and industrial activities, respectively; and (iii) the previously known pollution focus was clearly detected. The magnitude of contamination was estimated by means of a comparison between local backgrounds and concentrations of metals measured. The distance of aquatic bryophytes from the center of the river was negatively correlated with metal concentrations, which suggests that this factor should be taken into account in the implementation of sampling protocols.

Biomonitoring of trace elements with lichens in Veneto (NE Italy)

The concentrations of 13 elements in peripheral parts of the epiphytic lichen Xanthoria parietina were measured at 200 stations of Veneto (NE Italy). For each element, two maps are presented, showing, respectively, geographic patterns and deviations from background levels. The results are summarized by a map, showing the joint distribution of elements with concentrations close to Italian backgrounds, and of those strongly deviating from background levels. The results allow selection of high-risk areas for instrumental monitoring.