Although small bags containing living or dead moss or lichens are widely used to monitor persistent atmospheric pollutants in urban and industrial environments, uptake mechanisms and the reliability of this approach have been scarcely investigated. Shoots of the moss Hypnum cupressiforme Hedw. and lobes of the lichen Pseudevernia furfuracea (L.) Zopf from unpolluted areas were pre-treated by: 1) water washing (WL, WM); 2), oven drying at 120 °C for 24 h (OL, OM); 3) HNO3 washing (AL, AM); 4) NH4-oxalate extraction at 85 °C for 15 h (OLoxa, OMoxa, ALoxa, AMoxa). Four bags with 500 mg of each material were exposed for six weeks in Trieste and Naples (Italy) on the roof of automatic devices for continuous recording of NOx, SO2, CO, PM10, and climatic data. Two synthetic materials (A: quartz fibre filter Whatman QMA 1851047; B: cation-exchange filter Pall ICE 450) were exposed in the same conditions to compare uptake processes and accumulation capacity with bio-materials. 15 elements were analysed before and after exposure. CO2 gaseous exchange, chlorophyll fluorescence, chlorophyll content, and K, Ca and Mg intra- and extra-cellular distribution assessed in WL and WM. Results demonstrate that WM vitality was drastically reduced after the exposure in both sites, whereas WL vitality was mostly unmodified as shown by increased C and N content at levels reflecting CO and NOx pollution. Average concentrations (µg g-1 dry wt) of trace metals increased significantly in all materials and were scarcely influenced by the vitality or type of pre-treatment, although concentrations were always higher in moss shoots than in lichen lobes. For a reliable comparison between synthetic and biological materials, the specific surface area was estimated and concentrations expressed as ng cm-2. This resulted in similar concentrations in moss shoots and lichen lobes but significantly lower concentrations in synthetic materials. Passive capture of airborne particulate matter accounted for most of the metal uptake.
Lichen and moss bags as monitoring device: active or passive uptake of trace metals? / Adamo, Paola; Agnorelli, C.; Bargagli, R.; Baruffo, L.; Giordano, Simonetta; Modenesi, P.; Orlando, S.; Pittao, E.; Tretiach, M.. - STAMPA. - (2004), pp. 67-67. (Intervento presentato al convegno 5th IAL Symposium tenutosi a Tartu, Estonia nel 16-21 agosto 2004).
Lichen and moss bags as monitoring device: active or passive uptake of trace metals?
ADAMO, PAOLA;GIORDANO, SIMONETTA;
2004
Abstract
Although small bags containing living or dead moss or lichens are widely used to monitor persistent atmospheric pollutants in urban and industrial environments, uptake mechanisms and the reliability of this approach have been scarcely investigated. Shoots of the moss Hypnum cupressiforme Hedw. and lobes of the lichen Pseudevernia furfuracea (L.) Zopf from unpolluted areas were pre-treated by: 1) water washing (WL, WM); 2), oven drying at 120 °C for 24 h (OL, OM); 3) HNO3 washing (AL, AM); 4) NH4-oxalate extraction at 85 °C for 15 h (OLoxa, OMoxa, ALoxa, AMoxa). Four bags with 500 mg of each material were exposed for six weeks in Trieste and Naples (Italy) on the roof of automatic devices for continuous recording of NOx, SO2, CO, PM10, and climatic data. Two synthetic materials (A: quartz fibre filter Whatman QMA 1851047; B: cation-exchange filter Pall ICE 450) were exposed in the same conditions to compare uptake processes and accumulation capacity with bio-materials. 15 elements were analysed before and after exposure. CO2 gaseous exchange, chlorophyll fluorescence, chlorophyll content, and K, Ca and Mg intra- and extra-cellular distribution assessed in WL and WM. Results demonstrate that WM vitality was drastically reduced after the exposure in both sites, whereas WL vitality was mostly unmodified as shown by increased C and N content at levels reflecting CO and NOx pollution. Average concentrations (µg g-1 dry wt) of trace metals increased significantly in all materials and were scarcely influenced by the vitality or type of pre-treatment, although concentrations were always higher in moss shoots than in lichen lobes. For a reliable comparison between synthetic and biological materials, the specific surface area was estimated and concentrations expressed as ng cm-2. This resulted in similar concentrations in moss shoots and lichen lobes but significantly lower concentrations in synthetic materials. Passive capture of airborne particulate matter accounted for most of the metal uptake.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
