A comparative study for results obtained using biomonitors and PM10 collectors in Sado Estuary

Contribution of submicronic (PM1) and coarse (PM>1) particulate matter deposition to the heavy metal load of lichens transplanted along a busy road

The aim of this study was to estimate the contribution of submicronic (PM1) and coarse (PM > 1) particulate matter deposition to the heavy metal load of lichens exposed along a busy road, based on the assumption that the accumulation of heavy metals occurs mostly as particles. We tested the hypothesis that lichens exposed inside a nylon cover with mesh size of 1 μm accumulate less heavy metals than lichens exposed without any cover. To this purpose, thalli of the lichen Evernia prunastri were transplanted for three months along a busy road of the urban area of Siena (Central Italy), with half of the samples exposed inside a nylon cover with a mesh size of 1 μm. The content of Al, As, Cd, Cr, Cu, Fe, Ni, Pb, Sb, and Zn was measured by ICP-MS before and after the exposure. The results showed that samples exposed inside the nylon cover accumulated a lower amount of most chemical elements and that Sb, along with Cd and Cu were the main traffic-related elements in the study area. Differences in element uptake were not caused by differences in sample vitality caused by the experimental procedure. Using a conversion factor it was possible to estimate element deposition rates for PM1 and PM > 1.

Current knowledge on Parmelia genus: Ecological interest, phytochemistry, biological activities and therapeutic potential

Parmelia Acharius is one of the most representative genera within Parmeliaceae family which is the largest and the most widespread family of lichen-forming fungi. Parmelia lichens present a medium to large foliose thallus and they are distributed from the Artic to the Antartic continents, being more concentrated in temperate regions. According to its current description, the genus encompasses up to 41 different species and it is phylogenetically located within the Parmelioid clade (the largest group in the family). Interestingly, some of its species are among the most common epiphytic lichens in Europe such as Parmelia sulcata Taylor and Parmelia saxatilis (L.) Ach. The present work aims at providing a complete overview of the existing knowledge on the genus, from general concepts such as taxonomy and phylogeny, to their ecological relevance and biological interest for pharmaceutical uses. As reported, Parmelia lichens arise as valuable tools for biomonitoring environmental pollution due to their capacity to bioaccumulate metal elements and its response to acid rain. Moreover, they produce a wide array of specialized products/metabolites including depsides, depsidones, triterpenes and dibenzofurans, which have been suggested to exert promising pharmacological activities, mainly antimicrobial, antioxidant and cytotoxic activities. Herein, we discuss past and recent data regarding to the phytochemical characterization of more than 15 species. Even though the knowledge is still scarce in comparsion to other groups of organisms such as higher plants and other non-lichenized fungi. Reviewed works suggest that Parmelia lichens are worthy of further research for determining their actual possibilities as sources of bioactive compounds with potential therapeutic applications.

Biomonitoring of atmospheric pollution: a novel approach for the evaluation of natural and anthropogenic contribution to atmospheric aerosol particles

The investigation of the potential natural and anthropogenic contribution to atmospheric aerosol particles by using lichen-bag technique was performed in the Agri Valley (Basilicata region, southern Italy). This is an area of international concern since it houses one of the largest European on-shore reservoirs and the biggest oil/gas pre-treatment plant (i.e., Centro Olio Val d'Agri (COVA)) within an anthropized context. In particular, the concentrations of 17 trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Ti, and Zn) were measured in lichen bags exposed in 59 selected monitoring points over periods of 6 months (from October 2011 to April 2012) and 12 months (from October 2011 to October 2012). The general origin of the main air masses affecting the sampling site during the study period was assessed by the back trajectories clustering calculated using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results allowed the identification and characterization of the crustal material, smoke, sea salt, sulfate, and anthropogenic trace element contributions to the atmospheric aerosol particles in the study area. Finally, the application of the trend surface analysis (TSA) allowed the study of the spatial distribution of the considered contributions highlighting the existence of a continuous broad variation of these contributions in the area of interest.

Accumulation of polycyclic aromatic hydrocarbons by lichen transplants: Comparison with gas-phase passive air samplers

This study compared the accumulation of 16 polycyclic aromatic hydrocarbons (PAHs) in samples of the lichen Evernia prunastri exposed for 3 months in and around an industrial area of S Italy with that in co-located passive gas-phase air samplers. The results showed a strong linear correlations (R=0.96, P<0.05) between total PAHs in lichens and in passive samplers, clearly indicating that lichen transplants may provide direct quantitative information on the atmospheric load by total PAHs, allowing translation of lichen values into atmospheric concentrations. To the best of our knowledge this is the first study reporting such a correlation with gas-phase passive air samplers.

Influence of sample cleaning prior to the analysis on the elemental content of the lichen Xanthoria parietina (L.) Th.Fr

In this paper we investigated whether a different accuracy in sample cleaning prior to the analysis may affect the elemental composition of unwashed samples of the lichen Xanthoria parietina. To this purpose, samples of this lichen were collected from a remote area of Sardinia (Italy) and randomly divided into two aliquots, one cleaned very carefully (ca. 3-4 h to obtain ca. 200 mg of material for analysis) and the other cleaned with a lower efficiency (ca. 1-2 h). Samples were analysed by ICP-MS for the content of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, V and Zn. The results indicated that an accurate cleaning is effective for reducing the content of Al and Fe, i.e. soil-related elements, but that it has no effect on the concentrations of other elements less represented in the soil.

Lichen and moss bags as monitoring devices in urban areas. Part II: trace element content in living and dead biomonitors and comparison with synthetic materials

Lobes of the lichen Pseudevernia furfuracea (L.) Zopf and shoots of the moss Hypnum cupressiforme Hedw. were subjected to different treatments (water washing, oven drying, HNO3 washing, NH4-oxalate extraction) to assess the influence of vitality on accumulation efficiency, during a 6-week exposure in bags in two Italian cities, Trieste and Naples. No trend emerged between treatments, in terms of accumulation ability, for major and trace elements. Only water-washed lichens showed an increased C and N content after exposure in both cities. Element concentrations generally reached higher values in mosses than in lichens, especially for Al, Fe, and Zn (both cities), and for Cu, Mg and Na (Naples). Surface development strongly influenced accumulation capacity of the biomonitors. Quartzose and cation exchange filters revealed, on a weight basis, a poor performance. In urban environments, surface interception of atmospheric particulate seems to play a major role in accumulation, irrespective of organism vitality.

Use of lichens as pollution biomonitors in remote areas: comparison of PAhs extracted from lichens and atmospheric particles sampled in and around the Somport tunnel (Pyrenees)

Lichens of the species Parmelia sulcata were collected from sites on both sides of the Somport tunnel (which links France and Spain) and atmospheric particles were collected by air samplers installed within and on either side of the tunnel. Polycyclic aromatic hydrocarbons (PAHs) in the lichen and particle samples were then extracted, identified, quantified, and compared to evaluate the potential utility of lichens as pollution biomonitors in remote areas. The origin of the PAHs was also assessed using the Phe/Ant, Flu/Pyr, Ant/Ant+Phe, Flu/Flu+Pyr, and BaA/BaA+Chr concentration ratios. The total concentration of 16 priority PAHs ranged from 6.79 to 23.3 microg/g in particles outside the tunnel, from 18.3 to 265.2 microg/g in particles inside the tunnel, and from 0.91 to 1.92 microg/g in the lichen samples. The PAH ratios found in the lichens and particulate matter indicate that they were of pyrogenic origin and that road traffic was a major contributor. Results from the lichen samples suggest that they may be excellent biomonitors of pollution in remote areas.