Volcanic and anthropogenic contribution to heavy metal content in lichens from Mt. Etna and Vulcano island (Sicily)

A Review on Atmospheric Analysis Focusing on Public Health, Environmental Legislation and Chemical Characterization

Atmospheric pollution has been considered one of the most important topics in environmental science once it can be related to the incidence of respiratory diseases, climate change, and others. Knowing the composition of this complex and variable mixture of gases and particulate matter is crucial to understand the damages it causes, help establish limit levels, reduce emissions, and mitigate risks. In this work, the current scenario of the legislation and guideline values for indoor and outdoor atmospheric parameters will be reviewed, focusing on the inorganic and organic compositions of particulate matter and on biomonitoring. Considering the concentration level of the contaminants in air and the physical aspects (meteorological conditions) involved in the dispersion of these contaminants, different approaches for air sampling and analysis have been developed in recent years. Finally, this review presents the importance of data analysis, whose main objective is to transform analytical results into reliable information about the significance of anthropic activities in air pollution and its possible sources. This information is a useful tool to help the government implement actions against atmospheric air pollution.

Two lichens differing in element concentrations have similar spatial patterns of element concentrations responding to road traffic and soil input

Two epiphytic lichens (Xanthoria alfredii, XAa; X. ulophyllodes, XAu) and soil were sampled at three sites with varied distances to a road in a semiarid sandland in Inner Mongolia, China and analyzed for concentrations of 42 elements to assess the contribution of soil input and road traffic to lichen element burdens, and to compare element concentration differences between the two lichens. The study showed that multielement patterns, Fe:Ti and rare earth element ratios were similar between the lichen and soil samples. Enrichment factors (EFs) showed that ten elements (Ca, Cd, Co, Cu, K, P, Pb, S, Sb, and Zn) were enriched in the lichens relative to the local soil. Concentrations of most elements were higher in XAu than in XAa regardless of sites, and increased with proximity to the road regardless of lichen species. These results suggested that lichen element compositions were highly affected by soil input and road traffic. The narrow-lobed sorediate species were more efficient in particulate entrapment than the broad-lobed nonsorediate species. XAa and XAu are good bioaccumulators for road pollution in desert and have similar spatial patterns of element concentrations for most elements as response to road traffic emissions and soil input.

Recognition of Trace Element Contamination Using Ficus macrophylla Leaves in Urban Environment

Urban areas are characterized by numerous pollutants emitted by anthropic sources both in the form of solid and gaseous particulates. Biomonitoring is an easy, economical, and accessible approach for the determination of atmospheric pollutants. In this study, we used the leaves of Ficus macrophylla Desf. ex Pers., collected in the city of Palermo (Italy), to determine major and trace elements. Geogenic elements exhibited the highest concentrations, making up 99% of the weight of the analyzed elements (Ca, K, Mg, P, S, Na, Fe, and Al); they range 21,400 (Ca) to 122 µg g⁻¹ (Al). The remaining elements showed median concentrations in the range 47.5–0.05 µg g⁻¹ in the following order of abundance: Sr > Cu > Mn > Zn > Br > Rb > Ba > Pb > Cr > Sb > As > Mo = Sc. Cluster analysis, with Spearman’s coefficient to measure sample similarity, identified five main groups, namely, three clusters related to the geogenic background and marine spray; one cluster linked to elements essential to plants, and a final group attributed to the influence of traffic emissions. Calculated enrichment factors (EF) showed that the enrichments found for P and K were linked to plant metabolism; Na and Mg confirmed the role of sea spray; Cu and Zn underlined the contribution linked to anthropic processes and the role of micronutrients in plants.. As, Cr, and Mo had EF values ranging from 10 and 20, and Sb had EF > 90. From geochemical distribution maps of As, Cr, Mo, and Sb it was observed that metal and metalloid concentrations were higher in urban areas and immediately decreased as one moved away from these areas. Local pollution sources play a great role in trace element concentrations in airborne particulate matter. The present study confirms that Ficus macrophylla leaves are suitable for screening an urban environment to identify concentrations of inorganic chemicals, since they have high tolerance to pollution.

Anthropogenic Influences on Environmental Changes of Lake Bosten, the Largest Inland Freshwater Lake in China

A short lacustrine sediment core (41 cm) from Lake Bosten in arid central Asia was used to investigate the environmental changes that occurred in the past ≈150 years based on the superposition of climate and anthropogenic factors. Geochemical elements, total organic carbon (TOC) and nitrogen (TN), and stable isotope data (δ13Corg and δ15N) were used to identify abnormal environmental changes. The average C/N ratio in the sediments of Lake Bosten suggested that the organic matter in lake sediments was mainly from aquatic plants. The δ13Corg and δ15N in the lake sediments mainly reflect changes in the structure of the lake’s ecosystem. Before the 1960s, the primary productivity of the lake was relatively low with a relatively stable lake water environment. From the 1960s to the mid-1980s, the lake’s ecosystem was closely related to a significant decline in water levels caused by human activities and an increase in salinity. From the late 1980s to ≈2000, the aquatic plant structure of Lake Bosten did not change significantly. After 2000, the upper part of the sedimentary record suggested enhanced productivity due to urban and industrial development in the catchment area. However, sedimentary perspectives of the responses of different environmental proxies in sediments to human activities were anisochronous, and the increasing heavy metal (Pb and Cu) and P accumulations appeared in 1970, reflecting heightened human impacts. Through the comparison between the Aral Sea and Lake Bosten, it was inferred that, under the intervention of human activities, the lake experienced a completely different evolution trend. Humans, as geological agents, should protect our living environment while satisfying social development. The results will provide an important supplement to a large spatial scale study of the influences of human activities on the environment in Central Asia, which also has some significant implications for the protection of the ecological environment and the realization of sustainable development in arid regions.

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.

Major and trace elements in Boletus aereus and Clitopilus prunulus growing on volcanic and sedimentary soils of Sicily (Italy)

The aim of this study was to determine and compare the content of 28 elements (Ag, Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Rb, Sb, Se, Sr, Tl, U, V and Zn) in fruiting bodies of Boletus aereus Bull. and Clitopilus prunulus P. Kumm collected from eleven unpolluted sites of Sicily (Italy) and, also to relate the abundance of chemical elements in soil with their concentration in mushrooms. Median concentrations of the most abundant elements in Boletus aereus ranged from 31,290 μg/g (K) to 107 μg/g (Zn) in caps and from 24,009 μg/g (K) to 57 μg/g (Zn) in stalks with the following abundance order: K > Na > Ca > Mg > Fe > Al > Rb > Zn. The same elements, in the whole fruiting body of Clitopilus prunulus samples, varied in the range 54,073-92 μg/g following the abundance order: K > Na > Mg > Ca > Fe > Al > Rb > Zn. Metal contents in Boletus aereus and in the whole fruiting body of Clitopilus prunulus, collected from the same sampling sites, showed statistically significant differences for most elements. In particular, Clitopilus prunulus contained around two to four times more Co, Cr, Fe, Mg, Mo, Pb, U and V than caps and stalks of Boletus aereus species which, in turn, was from two to four times more enriched in Cu, Se and Tl. Thus, the elemental content of Boletus aereus and Clitopilus prunulus appeared to be species-dependent. The distribution of chemical elements in Boletus aereus was not uniform throughout the whole fruiting body as most elements were significantly bioconcentrated in caps. Furthermore, the fruit bodies of Boletus aereus from the volcanic soil differed both in major and minor elements concentrations from those collected from sedimentary soils. Cadmium and lead concentrations were below the threshold limits for wild mushrooms proposed by EU Directives (2008 and 2015). The elemental content was not significantly influenced by soil pH.

Perturbation vectors to evaluate air quality using lichens and bromeliads: a Brazilian case study

Samples of one lichen species, Parmotrema crinitum, and one bromeliad species, Tillandsia usneoides, were collected in the state of Rio de Janeiro, Brazil, at four sites differently affected by anthropogenic pollution. The concentrations of aluminum, cadmium, copper, iron, lanthanum, lead, sulfur, titanium, zinc, and zirconium were determined by inductively coupled plasma-atomic emission spectroscopy. The environmental diagnosis was established by examining compositional changes via perturbation vectors, an underused family of methods designed to circumvent the problem of closure in any compositional dataset. The perturbation vectors between the reference site and the other three sites were similar for both species, although body concentration levels were different. At each site, perturbation vectors between lichens and bromeliads were approximately the same, whatever the local pollution level. It should thus be possible to combine these organisms, though physiologically different, for air quality surveys, after making all results comparable with appropriate correction. The use of perturbation vectors seems particularly suitable for assessing pollution level by biomonitoring, and for many frequently met situations in environmental geochemistry, where elemental ratios are more relevant than absolute concentrations.

Elemental compositions of lichens from Duolun County, Inner Mongolia, China: Origin, road effect and species difference

To assess the response of lichen elemental compositions to road traffic and species difference in the context of high dust input and anthropogenic emissions, two foliose epiphytic lichens (Phaeophyscia hirtuosa, PHh; Candelaria fibrosa, CAf) were sampled near a road adjacent to Dolon Nor Town (Duolun County, Inner Mongolia, China). Twenty elements (Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Sr, Ti, V and Zn) in lichen and surface soil samples were analysed using inductively coupled plasma mass spectrometer (ICP-MS). The results demonstrate that lichen elemental compositions are highly influenced by both their natural environment and anthropogenic input. Windblown dust associated with sand dunes and degraded/desertified steppes represents the predominant source of lichen elements. Road traffic can enhance the lichen elemental burden by increasing the number of soil particles. Anthropogenic emissions from the town and road traffic have also led to the enrichment of Cd and Zn in lichens. PHh was higher than CAf in concentrations of 14 terrigenous metals. Both lichens are applicable to biomonitoring of atmospheric element deposition and, in most cases, yield comparable results.

Elemental content of mosses and lichens from Livingston Island (Antarctica) as determined by instrumental neutron activation analysis (INAA)

The total content of 8 major and 32 trace elements in four species of mosses and two of lichens as well as neighboring soil and rocks collected from different places of the Livingston Island Antarctica was determined by instrumental neutron activation analysis. The main goals of the project consisted of evidencing the possible trace of anthropogenic contamination as well as the influence of altitude on the distribution of considered elements. In the absence of a unanimously accepted descriptor, enrichment factor, geo-accumulation, and pollution load indices with respect to soil and rocks were used. The data, interpreted within the model of a reference plant, were compared with previous studies regarding the same organisms in similar geographic and climatological areas. The experimental results evidenced different capacity of mosses and lichens to retain the considered elements, but within experimental uncertainties, no traces of anthropogenic pollution were found. At the same time, it was found that the content of most of the elements decreased with the altitude.

Bioaccumulation of trace elements in the sandhopper Talitrus saltator (Montagu) from the Ionian sandy coasts of Sicily

The Ionian beaches of Sicily are of particular ecological interest because they include the basin of the largest active volcano in Europe and hosts both sites subject to natural protection constraints, as well as important industrial settlements. Consequently, the possibilities for these areas to become polluted are numerous. The sandhopper Talitrus saltator has proven to be a good bioindicator of contamination by numerous trace metals on some European coasts. Nevertheless, no data are available for the populations inhabiting the shores of the southern Mediterranean. Now, as metal accumulation has been shown to vary intraspecifically, the aim of this study was to evaluate trace metal accumulation in adults of T. saltator inhabiting Ionian coastal areas of Sicily and make an assessment of natural and anthropogenic metal pollution of this strip of coast. We also extended our survey to As, Co, Mo, Se, Sn and V never investigated before in this species. Significant differences in metal concentration among sites were found in both sand samples and amphipod tissues. The highest metal content was observed near the mouth of Simeto, the longest river of Sicily which collects waters coming from the volcanic territory of Mount Etna. The bioaccumulation of Cd, Cu, Hg and Zn in T. saltator is fully confirmed; it is also proven for As and Mo and assumed for Cr, Fe, Mn and V. Our outcomes let us to evaluate the prevailing influence of telluric contamination of the Ionian sandy shores of Sicily by trace metals. We also come to the conclusion that in the northern sites, pollution originates from volcanic emission while anthropogenic influence prevails in the southern ones.

Penalized linear discriminant analysis and Discrete AdaBoost to distinguish human hair metal profiles: The case of adolescents residing near Mt. Etna

The research focus of the present paper was twofold. First, we tried to document that human intake of trace elements is influenced by geological factors of the place of residence. Second, we showed that the elemental composition of human hair is a useful screening tool for assessing people's exposure to potentially toxic substances. For this purpose, we used samples of human hair from adolescents and applied two robust statistical approaches. Samples from two distinct geological and environmental sites were collected: the first one was characterized by the presence of the active volcano Mt. Etna (ETNA group) and the second one lithologically made up of sedimentary rocks (SIC group). Chemical data were statistically processed by Penalized Linear Discriminant Analysis (pLDA) and Discrete AdaBoost (DAB). The separation between the two groups turned out well, with few overlaps accounting for less than 5%. The chemical variables that better distinguished ETNA group from SIC group were As, Cd, Co, Li, Mo, Rb, Sr, U and V. Both pLDA and DAB allowed us to characterize the elements most closely related to the volcanic contribution (As, U and V) and those (Cd, Co, Li, Mo, Rb and Sr) prevalently influenced by the geology of the area where SIC samples were collected. We conclude that the geological characteristics of the area of residence constitute a key factor in influencing the potential exposure to trace elements. Hair analysis coupled with robust statistical methods can be effectively used as a screening procedure to identify areas at great environmental risk.

Use of the lichen Xanthoria mandschurica in monitoring atmospheric elemental deposition in the Taihang Mountains, Hebei, China

Air pollution is a major concern in China. Lichens are a useful biomonitor for atmospheric elemental deposition but have rarely been used in North China. The aim of this study was to investigate the atmospheric depositions of 30 trace elements (Al, Ba, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Sc, Sm, Sr, Tb, Th, Ti, Tl, V and Zn) in a region of the Taihang Mountains, Hebei Province, China using lichens as biomonitors. Epilithic foliose lichen Xanthoria mandschurica was sampled from 21 sites and analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The results show that 1) eight elements (Cd, Cr, Cu, Mo, P, Pb, Sb and Zn) are of atmospheric origin and are highly influenced by the atmospheric transportation from the North China Plain, as well as local mining activities, while 2) the remaining 22 elements are primarily of crustal origin, the concentration of which has been enhanced by local mining and quarrying activities. These results clearly validate the applicability of lichens in biomonitoring of atmospheric elemental deposition and demonstrate the spatial pattern for air pollution in the region.

Spatial and vertical distribution of metals in sediment cores from Río Espíritu Santo estuary, Puerto Rico, United States

The concentration and distribution of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were investigated in three sediment cores representing 100-150years of accumulation in upriver, midriver, and estuarine environments in Río Espíritu Santo (RES), Puerto Rico. Grain-size distribution, organic matter and carbonate content were determined to assess their influence on metal concentrations. Minimum biotoxicity levels of Ni and Cu were exceeded in the upriver and midriver sites, while the minimum biotoxicity level of Cu was exceeded in the estuarine location. Pb concentration decreased by ~35% in the upper portion of the midriver and estuarine cores compared to downcore concentrations as a consequence of leaded gasoline regulation. Enrichment Factors and Geoaccumulation Indices were calculated for each metal revealing high levels of Cu in all three cores, likely from an igneous source. Our results provide a baseline for metal contamination in an area facing further land use change.

Spatial distribution and source identification of trace elements in topsoil from heavily industrialized region, Aliaga, Turkey

Topsoil samples (n = 40) were collected from a heavily industrialized region in Turkey. The region includes several scrap processing iron-steel plants with electric arc furnaces (EAFs), a petroleum refinery, a petrochemical complex, steel rolling mills, a natural gas-fired power plant, ship-breaking yards and very dense transportation activities. The region has undergone a rapid transition from an agricultural region to a heavily industrialized region in the last three decades. Collected soil samples were analyzed for 48 trace elements using inductively coupled plasma-mass spectrometry (ICP-MS). The elemental distribution pattern in the region indicated that Nemrut area with dense iron-steel production activities was a hotspot for elemental pollution. In addition to crustal elements, concentrations of anthropogenic trace elements (i.e., Fe, Zn, Pb, Mn, Cu, Cd, Cr and Mo) were very high in the area influencing many parts of the region. Elemental compositions of fugitive sources polluting the soil (i.e., paved and unpaved roads, slag piles, EAFs filter dust piles and coal piles) were also determined. The methods (enrichment factors [EFs] and the index of geoaccumulation [Igeo]) used for determination of pollution status of soil showed that Cr, Ag, Zn, As and Pb were the strongly contaminating elements for the region. Principal component analysis (PCA) clearly indicated that anthropogenic sources (steel production, refinery and petrochemical processes and traffic) were important sources in this region.

Trace elements in scalp hair of children chronically exposed to volcanic activity (Mt. Etna, Italy)

The aim of this survey was to use scalp hair as a biomonitor to evaluate the environmental exposure to metals and metalloids of schoolchildren living around the Mt. Etna area, and to verify whether the degree of human exposure to trace elements is subject to changes in local environmental factors. Twenty trace elements were determined in 376 samples of scalp hair from schoolboys (11-13 years old) of both genders, living in ten towns located around the volcanic area of Mt. Etna (Sicily). The results were compared with those (215 samples) from children living in areas of Sicily characterized by a different geological setting (reference site). As, U and V showed much higher concentrations at the volcanic site whereas Sr was particularly more abundant at the reference site. Linear Discriminant Analysis (LDA) indicated an Etna factor, made up of V, U and Mn, and a second factor, concerning the reference site, characterized by Ni and Sr, and to a lesser extent by Mo and Cd. Significant differences in element concentrations were also observed among three different sectors of Mt. Etna area. Young people living in the Mt. Etna area are naturally exposed to enhanced intakes of some metals (V, U, Mn) and non-metals (e.g., As) than individuals of the same age residing in other areas of Sicily, characterized by different lithologies and not influenced by volcanic activity. The petrographic nature of local rocks and the dispersion of the volcanic plume explain the differences, with ingestion of water and local food as the most probable exposure pathways.

Trace element biomonitoring using mosses in urban areas affected by mud volcanoes around Mt. Etna. The case of the Salinelle, Italy

Trace element impact was assessed using mosses in a densely inhabited area affected by mud volcanoes. Such volcanoes, locally called Salinelle, are phenomena that occur around Mt. Etna (Sicily, Italy) and are interpreted as the surface outflow of a hydrothermal system located below Mt. Etna, releasing sedimentary fluids (hydrocarbons and NaCl brines) along with magmatic gases (mainly CO(2) and He). To date, scarce data are available about the presence of trace elements, and no biomonitoring campaigns are reported about the cumulative effects of such emissions. In this study, concentrations of Al, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, V, and Zn were detected in the moss Bryum argenteum, in soil and water. Results showed that the trace element contribution of the Salinelle to the general pollution was significant for Al, Mn, Ni, and Zn. The comparison of trace concentrations in mosses from Salinelle and Etna showed that the mud volcanoes release a greater amount of Al and Mn, whereas similar values of Ni were found. Natural emissions of trace elements could be hazardous in human settlements, in particular, the Salinelle seem to play an important role in environmental pollution.

Bioindication of volatile elements emission by the Puyehue-Cordón Caulle (North Patagonia) volcanic event in 2011

The emission of volatile pollutants from the volcanic eruption of the Puyehue-Cordón Caulle complex (North Patagonia Andean Range) that started in June 4th, 2011, was investigated by bioindication means with the epyphytic fruticose lichen Usnea sp. The elemental composition of pooled samples made up with 10 lichen thalli were analysed by Instrumental Neutron Activation Analysis. Eleven sampling sites were selected within the impacted region at different distance from the volcanic source. Five sites were selected as they were already sampled in a previous study prior to the eruption. Two other new sampling sites were selected from outside the impacted zone to provide non-impacted baseline sites. The elements associated with the lichen incorporation of particulate matter (PM) of geological origin were identified by linear correlation with a geochemical tracer (Sm concentrations). The elements associated with PM uptake were Ce, Eu, Fe, Hf, La, Lu, Na, Nd, Sb, Sc, Se, Ta, Tb, Th, U, and Yb. Arsenic and Cs concentrations showed contributions exceeding the PM fraction in sites near the volcanic centre, also higher than the baseline concentrations, which could be associated with permanent emissions from the geothermal system of the Puyehue-Cordón Caulle complex. The lichen concentrations of Ba, Ca, Co, Hg, K, Rb, Sr, and Zn were not associated with the PM, not showing higher concentrations in the sites nearby the volcanic source or respect to the baseline values either. Therefore, there is no indication of the emission of volatile forms of these elements in the lichen records. The lichen records only identified Br volatile emissions associated with the Puyehue-Cordón Caulle complex eruption in 2011.

The use of tree-rings and foliage as an archive of volcanogenic cation deposition

Tree cores (Pinus nigra ssp. laricio) and leaves (Castanea sativa) from the flanks of Mount Etna, Sicily were analysed by ICP-MS to investigate whether volcanogenic cations within plant material provide an archive of a volcano's temporal and spatial depositional influence. There is significant compositional variability both within and between trees, but no systematic dendrochemical correlation with periods of effusive, explosive or increased degassing activity. Dendrochemistry does not provide a record of persistent but fluctuating volcanic activity. Foliar levels of bioaccumulated cations correspond to modelled plume transport patterns, and map short-term volcanic fumigation. Around the flanks of the volcano foliar variation is greater for volatile cations (Cs, Cd, Pb) than for lithophilic cations (Ba, Sr), consistent with trace-metal supply from volcanic aerosol during quiescent periods.

Introduction of the factor of partitioning in the lithogenic enrichment factors of trace element bioaccumulation in plant tissues

Bioindicators are widely used in the study of trace elements inputs into the environment and great efforts have been conducted to separate atmospheric from soil borne inputs on biomass accumulation. Many monitoring studies of trace element pollution take into account the dust particles located in the plant surface plus the contents of the plant tissues. However, it is usually only the trace element content in the plant tissues that is relevant on plant health. Enrichment factor equations take into account the trace element enrichment of biomasses with respect soil or bedrocks by comparing the ratios of the trace element in question to a lithogenic element, usually Al. However, the enrichment equations currently in use are inadequate because they do not take into account the fact that Al (or whichever reference element) and the element in question may have different solubility-absorption-retention levels depending on the rock and soil types involved. This constrain will become critical when results from different sites are compared and so in this article we propose that the solubility factors of each element are taken into account in order to overcome this constrain. We analysed Sb, Co, Ni, Cr, Pb, Cd, Mn, V, Zn, Cu, As, Hg, and Al concentration in different zones of Catalonia (NE Spain) using the evergreen oak Quercus ilex and the moss Hypnum cupressiforme as target species. We compared the results obtained in rural and non industrial areas with those from the Barcelona Metropolitan Area. We observed differences in Al concentrations of soils and bedrocks at each different site, together with the differences in solubility between Al and the element in question, and a weak correlation between total soil content and water extract content through different sites for most trace elements. All these findings show the unsuitability of the current enrichment factors for calculating lithospheric and atmospheric contributions to trace element concentrations in biomass tissues. The trace element enrichment factors were calculated by subtracting the part predicted by substrate composition (deduced from water extracts from soils and bedrock) from total concentrations. Results showed that for most of the trace elements analysed, trace elements enrichment factors were higher inside the Barcelona Metropolitan Area than outside, a finding that indicates that greater atmospheric inputs occur in urban areas. The results show that the most useful and correct way of establishing a reference for lithospheric and atmospheric inputs into the plant tissues is, first, to analyse samples of the same plant species collected from a number of sites possessing similar environmental conditions (climate, vegetation type, soil type) and, second, to use this new enrichment factor obtained by subtracting from the total concentration in plant tissue the predicted contribution of soil or bedrock extracts instead of that of total soil or bedrock concentrations.

Case study: inorganic pollutants associated with particulate matter from an area near a petrochemical plant

The area of Gela (Sicily, Italy) contains one of the largest petroleum refineries in Europe and also has several oil fields both on land and offshore. This paper discusses how the oil refinery and traffic-related air pollution affect the chemical composition of airborne particulate matter over the town of Gela, using pine needles and urban road dust as the means of survey. Forty-one samples of pine needles from Pinus halepensis (Mill.) and two composite samples of roadway dust, each subdivided into six size fractions, were analyzed for major and trace elements. Information on the natural or anthropogenic origin of the observed heavy metals was deduced from factor analysis and element distribution maps. Factor analysis was applied to a data set of 20 element concentrations in pine needles and identified three main sources of metals: soil, vehicle traffic, and industrial emissions. The petrochemical plant appears to be associated with raised levels of As, Mo, Ni, S, Se, V, and Zn. Similarly, enhanced Cu, Pb, Pt, Pd, Sb, and partly Zn concentrations are closely associated with traffic. High correlations between Ni and V, As and Se, and Pb and Sb were observed. Element distribution maps, showing a decrease in heavy metal contents immediately farther inland, confirm that local sources play a considerable role in heavy metal pollution. Morphological alterations and accumulation of phenols were observed in sections of Pinus halepensis needles collected from sites with high traffic density and industrial emissions.

Ion equilibrium in lichen surrounding

In laboratory conditions, the ionic equilibriums between a solution and a cation-active layer of epiphytic lichens Hypogymnia physodes immersed in the solution were examined. It was found that such equilibriums, due to exchange of mobile cations: H, Na, K, Ca, and Mg, are established in natural conditions between a lichen and atmospheric water.

Distinguishing between natural and anthropogenic sources for elements in the environment: regional geochemical surveys versus enrichment factors

High element enrichment factors (EFs) are commonly used in the literature to support the hypothesis that a particular suite of elements is of anthropogenic origin. Real-world examples of regional geochemical surveys demonstrate that EFs can be high or low due to a multitude of reasons, of which contamination is but one. This applies to EFs calculated relative to either the crust or some local background (e.g., a deeper soil layer). Results from local studies near industrial centres showing high (and pollution-related) EFs cannot be generalised over large areas or for sample sites far removed (i.e., more than some tens of kilometers) from a likely pollution source. Regional-scale geochemical mapping, on the other hand, facilitates the reliable estimation of the influence of contamination on the measured element concentrations. EFs are strongly influenced by, among other factors, biogeochemical processes that redistribute chemical elements between environmental compartments at the Earth's surface. Using EFs to detect or 'prove' human influence on element cycles in remote areas should be avoided because, in most cases, high EFs cannot conclusively demonstrate, nor even suggest, such influence.

The possible influence of volcanic emissions on atmospheric aerosols in the city of Colima, Mexico

An elemental composition study of atmospheric aerosols from the City of Colima, in the Western Coast of Mexico, is presented. Samples of PM(15)-PM(2.5) and PM(2.5) were collected with Stacked Filter Units (SFU) of the Davis design, in urban and rural sites, the latter located between the City of Colima and the Volcán de Colima, an active volcano. Elemental analyses were carried out using Particle Induced X-ray Emission (PIXE). The gravimetric mass concentrations for the fine fraction were slightly higher in the urban site, while the mean concentrations in the coarse fraction were equal within the uncertainties. High Cl contents were determined in the coarse fraction, a fact also observed in emissions from the Volcán de Colima by other authors. In addition to average elemental concentrations, cluster analysis based on elemental contents was performed, with wind speed and direction data, showing that there is an industrial contributor to aerosols North of the urban area. Moreover, a contribution from the volcanic emissions was identified from the grouping of S, Cl, Cu, and Zn, elements associated to particles emitted by the Volcán de Colima.

Environmental impacts of tropospheric volcanic gas plumes

Recent studies suggest that the environmental effects of volcanic gas emissions in the lower troposphere have been underestimated. This chapter first briefly summarizes the techniques available for characterizing tropospheric volcanic gas plumes, including the composition and fluxes of emitted gases and aerosols, as well as their atmospheric dispersion. The second part documents the contribution of gas emissions from degassing craters to the composition of the atmosphere, including effects from dry and wet deposition chemistry. The third section deals with the detrimental impacts on vegetation, soils, and groundwater in relation to passive degassing activity. Improved understanding of the impacts of volcanic degassing on the atmospheric and terrestrial environment will require: (1) systematic two-dimensional and three-dimensional measurements of tropospheric volcanic plumes, (2) development of general physical and chemical models to describe the fate of volcanic gases and aerosols during transport in the troposphere, and (3) investigation of the response of diverse ecosystems to volcanogenic air pollution.