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P L Nimis

Publications and source records attributed to P L Nimis.

8 recordsLinked to original sources
PubMed2006

Assessment of intermittent trace element pollution by moss bags.

Moss bags of the aquatic bryophyte Rhynchostegium riparioides (Hedw.) C. Jens. were transplanted into an irrigation ditch in the Province of Vicenza (NE Italy), affected by intermittent trace element contamination due to galvanics. The study aimed at: (a) testing the ability of mosses to detect different patterns of pollution, (b) providing information about intensity and temporal extension of pollution events, and (c) localising the main sources. Moss bags were collected after 20, 34, 48 and 62 days of exposure. The concentrations of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn in the desiccated apical shoots of mosses were determined by atomic absorption spectrophotometry. The mean concentrations measured in non-contaminated stations of a previous work were adopted as background values, to calculate the contamination factor (CF). Transplants were able to: (a) detect spatial patterns of bioaccumulation, (b) reveal chronic contamination by Pb and Cu, intermittent contamination by Cr, Zn, and Ni, and a release of Cd by moss bags, and (c) localise the main emission sources.

Biodegradation, Environmental↗
PubMed2004

Reliability of different sampling densities for estimating and mapping lichen diversity in biomonitoring studies.

Sampling requirements related to lichen biomonitoring include optimal sampling density for obtaining precise and unbiased estimates of population parameters and maps of known reliability. Two available datasets on a sub-national scale in Italy were used to determine a cost-effective sampling density to be adopted in medium-to-large-scale biomonitoring studies. As expected, the relative error in the mean Lichen Biodiversity (Italian acronym: BL) values and the error associated with the interpolation of BL values for (unmeasured) grid cells increased as the sampling density decreased. However, the increase in size of the error was not linear and even a considerable reduction (up to 50%) in the original sampling effort led to a far smaller increase in errors in the mean estimates (<6%) and in mapping (<18%) as compared with the original sampling densities. A reduction in the sampling effort can result in considerable savings of resources, which can then be used for a more detailed investigation of potentially problematic areas. It is, however, necessary to decide the acceptable level of precision at the design stage of the investigation, so as to select the proper sampling density.

Air Pollutants↗
PubMed2002

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.

Bryopsida↗
PubMed2001

The performance of two lichen species as bioaccumulators of trace metals.

The concentrations of 16 metals were measured in peripheral and central parts of the foliose epiphytic lichens Parmelia caperata and Xanthoria parietina collected in north-east Italy. Relevant intra- and interspecific variability was shown by multivariate analysis (classification and ordination) of the matrix of metals and samples. The central, older parts of the thalli contained significantly higher amounts of most metals in both species. Significative differences were also found between peripheral parts of the two species, with higher concentrations of Fe and Al in Xanthoria, and Cd and Zn in Parmelia. An inter-species comparison of several hundred Italian measurements confirmed the higher affinity of Parmelia for Cd and Zn, but not that of Xanthoria for Fe and Al. In order to enhance data quality in biomonitoring studies, it is suggested to analyse only peripheral parts of the lichens, and to avoid the joint use of Parmelia and Xanthoria when monitoring Cd and Zn.

Air Pollutants↗
PubMed2000

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.

Air Pollutants↗