Biomonitoring of atmospheric pollution by moss bags: Discriminating urban-rural structure in a fragmented landscape

Cross-media transfer of polycyclic aromatic hydrocarbons in the Naples metropolitan area, southern Italy

At present, an in-depth knowledge of polycyclic aromatic hydrocarbons (PAHs) in the multimedia system of the urban environment remains limited. Taking the Naples metropolitan area (NMA) for instance, we simulated the cross-media transfer of PAHs using a multimedia urban model, involving air, water, soil, sediment, vegetation, and impervious film. The results indicated that the predicted PAH values in 2015 match well with their corresponding in-situ monitoring data. The PAH emission inventory and the simulated mass in various media all showed a downward trend from 2015 to 2020 due to national energy conservation policies and Corona Virus Disease 2019. The simulated mass of PAHs in the soil and sediment phases was 896.8 and 232.7 kg in 2020, respectively, contributing together to 96.7% of PAHs in the NMA. And they were identified as the greatest sinks for PAHs, and exhibited the longest retention duration, with values of PAH persistence reaching approximately 548.8 - 2,0642.3 hours. The results of transfer fluxes indicated that local emissions and atmospheric advection were the primary routes affecting the distribution of PAHs. The sensitivity analysis indicated that atmospheric advection rate was the most critical parameter for air, soil, vegetation, and film, whereas water concentration and sediment degradation rate were vital for water and sediment, respectively. This study offered valuable insights into how human activity contributes to the status and fate of PAHs in the urban environment.

Assessment of the Atmospheric Deposition of Potentially Toxic Elements Using Moss Pleurozium schreberi in an Urban Area: The Perm (Perm Region, Russia) Case Study

Assessment of air quality in urban areas is very important because pollutants affect both the environment and human health. In Perm (Russia), a moss biomonitoring method was used to assess the level of air pollution. The concentrations of 15 elements in 87 samples of moss Pleurozium schreberi in the city territory were determined using a direct mercury analyzer and an inductively coupled plasma atomic emission spectroscopy. Using factor and correlation analyses, the grouping of elements and their relationship with emission sources were established. The main sources of emissions of potentially toxic elements are the transportation (road and rail), metallurgical, and chemical industries. The level of atmospheric air pollution was assessed by calculating the environmental risk index, pollutant load index, and pollution coefficient. Based on the values of the pollution index, the level of atmospheric air pollution in Perm varies from unpolluted to highly polluted, with moderate environmental risk.

Temporal and spatial biomonitoring of atmospheric heavy metal pollution using moss bags in Xichang

Heavy metal air pollution poses a serious threat to human health and the environment in Chinese tourist cities. In this study, we investigated the temporal and spatial variations of atmospheric heavy metal pollution using moss bags in Xichang, a tourist destination in Southwest China. The biomonitoring investigation used an indigenous moss (Taxiphyllum taxirameum) transplanted into bags. Moss bags were exposed to 22 sites including industrial, agricultural, urban/residential, tourist, and high-traffic sites, across four different seasons in 2019-2020. The results showed that T. taxirameum was a good biomonitor of air pollution in Xichang. Among the 22 sample points, air pollution was the worst along the G102 motorway. Heavy metal emissions varied in different regions and directions. Temporal changes significantly influenced the heavy metals accumulated in moss bags, with low deposition of most elements observed at nearly all sampling sites in summer. Different seasons and regions were important factors affecting atmospheric heavy metal pollution. Based on the correlation analysis and the positive matric factorization model, the results revealed that heavy metals in moss bags in Xichang were mainly derived from anthropogenic sources and atmospheric deposition. Overall, this research provides an important reference for air pollution monitoring in urban areas.

Modeling exposure to airborne metals using moss biomonitoring in cemeteries in two urban areas around Paris and Lyon in France

Exposure of the general population to airborne metals remains poorly estimated despite the potential health risks. Passive moss biomonitoring can proxy air quality at fine resolution over large areas, mainly in rural areas. We adapted the technique to urban areas to develop fine concentration maps for several metals for Constances cohort's participants. We sampled Grimmia pulvinata in 77 and 51 cemeteries within ∼50 km of Paris and Lyon city centers, respectively. We developed land-use regression models for 14 metals including cadmium, lead, and antimony; potential predictors included the amount of urban, agricultural, forest, and water around cemeteries, population density, altitude, and distance to major roads. We used both kriging with external drift and land use regression followed by residual kriging when necessary to derive concentration maps (500 × 500 m) for each metal and region. Both approaches led to similar results. The most frequent predictors were the amount of urban, agricultural, or forest areas. Depending on the metal, the models explained part of the spatial variability, from 6% for vanadium in Lyon to 84% for antimony in Paris, but mostly between 20% and 60%, with better results for metals emitted by human activities. Moss biomonitoring in cemeteries proves efficient for obtaining airborne metal exposures in urban areas for the most common metals.

Mobile Biomonitoring of Atmospheric Pollution: A New Perspective for the Moss-Bag Approach

In this work the potential of moving moss-bags, fixed to bicycles, to intercept particulate matter (PM) and linked metal(loid)s was tested for the first time. Seven volunteers carried three moss-bags for fifty days while commuting by bicycle in the urban area of Antwerp, Belgium. Moreover, one bike, equipped with mobile PM samplers, travelled along four routes: urban, industrial, green route and the total path, carrying three moss-bags at each route. The saturation isothermal remanent magnetization (SIRM) signal and chemical composition (assessed by HR-ICP-MS) of the moss samples indicated that the industrial route was the most polluted. Element fluxes (i.e., the ratio between element daily uptake and the specific leaf area) could discriminate among land uses; particularly, they were significantly higher in the industrial route for Ag, As, Cd and Pb; significantly lowest in the green route for As and Pb; and comparable for all accumulated elements along most urban routes. A comparison with a previous experiment carried out in the same study area using similar moss-bags at static exposure points, showed that the element fluxes were significantly higher in the mobile system. Finally, PM2.5 and PM10 masses measured along the four routes were consistent with element fluxes.

Monitoring Air Quality with Transplanted Bryophytes in a Neotropical Andean City

Air pollution is one of the main global environmental problems, where bryophytes, due to their high capacity to retain metals and other pollutants, have been widely used in active air quality monitoring studies in temperate and tropical zones. Thus, in this study, we analyzed for the first time the concentrations of eight metals (cadmium, copper, nickel, aluminum, iron, manganese, lead and zinc) in three species of transplanted mosses (Rhacocarpus purpurascens (Brid.) Paris, Sphagnum sp. and Thuidium delicatulum (Hedw.) Schimp.) from Ecuador. Significant differences were found for the three species in the concentrations of Al, Mn, Fe and Zn between urban and control areas, pointing to the Central zone as the main source of contamination with the highest concentrations of Al, Fe, Mn and Zn, related to vehicular traffic. Lead did not differ between zones for Rhacocarpus purpurascens and Sphagnum sp.; however, Thuidium delicatulum accumulated different concentrations between urban areas and the control areas. The three species of mosses provided valuable information on the contamination of Al, Fe, Mn, Pb and Zn in the urban area of the city of Loja, and therefore can be used in future air quality monitoring programs over time in tropical cities.

Translocation factor of heavy metals by elephant grass grown with varying concentrations of landfill leachate

The aim of this study is to obtain the translocation factor by application of landfill leachate (LL) diluted in public irrigation water (IW). Pennisetum purpureum Schum (elephant grass) was cultivated for 83 days in an experimental water reuse unit. The present work was developed at the Experimental Water Reuse Unit (UERA), on the UFERSA campus in Mossoró, RN, Brazil. Plot irrigation was based on water balance and crop evapotranspiration (ETc). The concentration in the plant tissue (root and leaf) of the following heavy metals was measured to determine the respective translocation factors: manganese (Mn), zinc (Zn), copper (Cu), nickel (Ni), cadmium (Cd), and lead (Pb). The experiment was set up in a randomized block design with five treatments (T1, plots irrigated only with IW; T2, 50% of LL dose plus IW; T3, 100% of LL dose plus IW; T4, 150% of LL dose plus IW; and T5, 200% of LL dose plus IW) and five replications. All treatments received LL plus IW depth of 491.02 mm for 83 days of P. purpureum cultivation. The data obtained were submitted to multivariate analysis plus the nonparametric Kruskal-Wallis test to compare the means. Pennisetum purpureum showed a potential to accumulate metals in its tissues, mainly Mn, Zn, and Cu. The treatments that most favored the extraction of these metals were T2 and T5; in this sense, P. purpureum was not efficient in translocating heavy metals, since the translocation factor observed in all treatments was below 1.0, indicating that the species used extract heavy metals from soil solution and keeps in yours roots. This suggests planting P. purpureum may not be a viable option to remediate environments highly contaminated with heavy metals.

A study of the spatial distribution patterns of airborne polycyclic aromatic hydrocarbons in crowberry (Empetrum nigrum) in Ilulissat, Greenland

Polycyclic aromatic hydrocarbons (PAHs) are produced by anthropogenic activities, such as traffic and domestic heating. Due to their adverse effects to humans and natural habitats, the presence of PAHs in the environment needs to be monitored. Plants are known as natural accumulators of persistent organic pollutants (POPs) and can therefore be used for the monitoring of PAHs emitted into the environment. Contamination by PAHs also occurs in the Arctic such as Greenland due to long-range transport through air. However, as anthropogenic activities in the Arctic are increasing, there is a need to investigate the distribution of PAHs due to local emission sources. In this study, we present a systematic sampling approach to identify the influence of PAH sources in an area next to the town of Ilulissat in Greenland. Composite crowberry samples have been collected north of Ilulissat, where the town itself, an incineration site and Ilulissat airport are possible emission sources for PAHs. Matrix solid-phase extraction was used for the extraction of PAHs and the chemical analysis was performed by gas chromatography with mass spectrometry detection (GC-MS). In total, 18 out of 19 investigated PAHs could be detected in Empetrum nigrum in a concentration range of 0.69 to 93.01 μg/kg_{dry weight}. Higher concentrations for most of the targeted PAHs were found close to the suspected emission sources and also along the road connecting them. For pyrene, the correlation between the concentration and the distance from the emission sources could be modelled and visualized using a two-dimensional exponential variogram and ordinary kriging. The range in which the samples were spatially correlated was approximately 500 m. Our results show that local emission sources contribute to the spatial distribution patterns of PAHs. Monitoring of pollution by airborne PAHs is therefore needed even in areas far from major pollution sources such as Ilulissat, Greenland. E. nigrum showed to be a feasible species for biomonitoring of PAHs due to its large abundance in the sampling area and its widespread availability in the Artic region.

Environmental pollution influence to soil-plant-air system in organic vineyard: bioavailability, environmental, and health risk assessment

This study was performed in organic vineyard to assess integrated pollution in soil-plant-air system by potentially toxic elements (PTE). Concentrations of 26 PTE were determined in soil, grapevine, and air biomonitors (moss bags) using ICP-OES and ICP-MS. Environmental implication assessment of soil did not show pollution by PTE, except for B in samples collected in the middle of grapevine season (July). Despite low total Cd concentrations in soil, it has the highest influence on increase of environmental risk. Based on biological accumulation concentration (BAC), grapevine is not hyperaccumulator of PTE from soil. Advanced classification algorithm, Kohonen self-organizing map (SOM), was applied to compare environmental implications in organic with conventional vineyards. PTE concentrations were significantly lower in organic than conventional grapevine. PTE concentrations were higher in the outer (leaf and petiole) than in the inner grapevine parts (skin, pulp, and seed). Some airborne elements have an influence on outer grapevine parts, especially on leaves (ratio factor-RF > 1). Moss bag technique testified about lower enrichment of airborne elements compared with the conventional vineyard and urban microenvironments. Environmental and health risk assessments confirmed that organic production is harmless for field workers and grape consumers.

Role of photo- and biodegradation of two PAHs on leaves: Modelling the impact on air quality ecosystem services provided by urban trees

Urban trees provide important ecosystem services, including air quality improvement. Polycyclic aromatic hydrocarbons (PAHs) are among the most important pollutants in air, due to their elevated concentrations and toxicity. Plants can act as filters of PAHs and as "chemical reactors" for pollutant removal, therefore reducing air concentrations. Here, the first assessment of photo- vs. biodegradation of PAHs on leaves of urban trees is presented. A dynamic air-vegetation-soil model (SoilPlusVeg) was improved to simulate the fate of two representative PAHs with contrasting physico-chemical properties (phenanthrene and benzo[a]pyrene). Simulations were performed for two different environmental scenarios from Italy (Como and Naples), selected for their dissimilar meteorological parameters, plant species and emission levels. The effect of photo- and biodegradation on leaf concentrations and fluxes towards air and soil was investigated comparing deciduous (maple, cornel and hazelnut) and evergreen (holm oak) broadleaf woods. The results showed that biodegradation in the phyllosphere could not be neglected when evaluating the ecosystem services provided by urban trees, as this process contributed significantly to the reductions (up to 25% on average) in PAH leaf concentrations and fluxes to air and soil; however, the reductions revealed ample variations with time (up to more than two orders of magnitude) showing the dependence on meteorological parameters, air compartment structure, as well as type of woods. These findings permitted to improve the ecological realism of the simulations and obtain more accurate results when predicting organic contaminant uptake and release by plant leaves, including potential for food chain transfer and long-range transport.

Mapping of atmospheric heavy metal deposition in Guangzhou city, southern China using archived bryophytes

Atmospheric heavy metal contamination is becoming a serious threat to environmental and human health in Chinese megacities. This study evaluated the concentrations of arsenic (As), cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) and Pb isotopic compositions in herbarium and native bryophytes collected from Guangzhou from 1932 to 2018. Relatively low mean metal concentrations were measured for bryophytes collected in the 1930s. The highest mean concentrations of Cd (0.72 ± 0.32 mg/kg), Cu (28.1 ± 9.8 mg/kg), Pb (125.9 ± 62.4 mg/kg) and Zn (273 ± 130 mg/kg) were found in the bryophytes from 1979 to 2000, following the commencement of the Reform and Opening-Up Program in 1978. The mean Pb concentrations (74.7 ± 6.3 mg/kg) decreased sharply from 2001 onwards, following the cessation of leaded petrol across the Chinese mainland in 2000. However, these values are still higher than those in 1950-1978, corresponding to a significant increase in atmospheric Pb emissions from coal combustion, nonferrous metal smelting and motor vehicle petrol consumption in China in the 2000s. The lead isotopic ratios of bryophyte archives (²⁰⁶Pb/²⁰⁷Pb 1.141-1.229, ²⁰⁸Pb/²⁰⁷Pb 2.376-2.482) indicate that lithogenic input and anthropogenic input arising from leaded petrol and industrial emissions have been the main sources of atmospheric heavy metal deposition in the city of Guangzhou over the past 85 years. Herbarium bryophyte can be utilised to reconstruct temporal and spatial shifts in atmospheric heavy metal deposition to better understand and manage the current air quality in Chinese megacities.

Air pollution tolerance, metal accumulation and dust capturing capacity of common tropical trees in commercial and industrial sites

Total nine tree species of common tropical trees were assessed for their air pollution tolerance, dust capturing capacity and possibility to act as metal bio-monitors in commercial, industrial and control sites. Two seasons sampling was done respectively in monsoon and post-monsoon, to study their seasonal variations. According to Air Pollution Tolerance Index (APTI) values Mangifera indica, Azadirachta indica and Ficus religiosa were the most tolerant species while Ficus bengalensis and Alstonia scholaris were intermediately tolerant towards air pollution. Single factor ANOVA of biochemical parameters between the sampling sites, revealed that APTI of plants did not vary significantly in both the seasons. Site-wise variation was significant both at commercial and industrial sites. The same trend of result was also found in Anticipated Performance Index (API) which also includes other social benefits. So, these species can be recommended for the green belt development in urban commercial and industrial areas. Ficus bengalensis, Ficus religiosa and Mangifera indica were also having the best dust capturing capacity as Scanning Electron Microscope image revealed that they have rough and large surface area of leaf with short petiole and large canopy structure. According to the Geoaccumulation index (Igeo) and Enrichment Factor (EF) of soil in the sampling sites were found to be contaminated with copper and cadmium. Psidium guajava, Mangifera indica, Alstonia scholaris and Ficus religiosa were found to be good phytoextractors of copper. They did not accumulate cadmium. So, these plants can be recommended as copper bioindicators. However, the metals accumulation efficiencies were high for Mangifera indica and Ficus religiosa.

Monitoring of Air Pollution by Moss Bags around an Oil Refinery: A Critical Evaluation over 16 Years

The present study analyzes the results of a biomonitoring campaign, carried out by means of Hypnum cupressiforme Hedw. moss bags around an oil refinery, located in the southwestern part of Sardinia island (Italy). This work focuses mainly on the effects of rainfall and distance from the source of contamination on the content of 14 trace elements measured over 16 years. In addition, to point out any increasing or decreasing trends, as well as any peak in presence of airborne pollutants in the area, annual elements’ concentration values are plotted and discussed. Coefficients of variation were also calculated on accumulation values in order to evaluate stability of measurements across the years and to evaluate if similar exposure conditions, i.e., humidity and distance from contamination source, resulted in more uniform accumulation values. In conclusion, (i) the vicinity of the source of contamination as well as rainfall influenced element content in the biomonitor in the case study differently, depending on the considered element and on the exposure condition, (ii) H. cupressiforme moss bags provided relatively stable measurements during the 16-year time frame (observed variations in elements content can be attributed to environmental inputs in the area), (iii) similar conditions of exposure determined less variable accumulation values.

Exploring the phytoremediation potential of Cynara cardunculus: a trial on an industrial soil highly contaminated by heavy metals

Metal uptake capacity and growth patterns of three cardoon cultivars (Sardo, Siciliano, and Spagnolo) were investigated for phytoremediation in a metal-contaminated soil. Metal concentrations after one and two growth rounds were measured in soil and plants by ICP-MS. Potentially and promptly available metal fractions were estimated by EDTA and ammonium nitrate. Plant weight, water and nitrogen content, and life span were considered as growth parameters. After the first growth cycle, a significant accumulation of all elements was observed in roots, whereas only Cd, Cu, Fe, Pb, and Sb were significantly translocated to the shoots. After the second growth cycle, a further significant increase, especially in roots, was observed in all cultivars and for all elements considered. High percentages of the potentially available fraction were found for As, Cd, Cu, Pb, and Sb. Metal concentrations in plants were far higher than the promptly available fraction, indicating an increase of metal bioavailability during culture rounds. A severe decrease of weight and life span was observed in Sardo and Siciliano grown on polluted soil, along with an increase in N content. The cultivar Spagnolo, harmonizing a high ability of metal uptake and tolerance, proved the most efficient cultivar in metal phytoremediation.

Morphological Traits Influence the Uptake Ability of Priority Pollutant Elements by Hypnum cupressiforme and Robinia pseudoacacia Leaves

In this paper, a biomonitoring survey of airborne priority pollutant elements was carried out using leaves of native black locust and moss bags filled with Hypnum cupressiforme. The aims of the work were (i) to evaluate if mosses and leaves provide similar information regarding the accumulation of the elements of environmental concern (As, Be, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Se, V, Zn, Tl); (ii) to evaluate if leaf traits are significantly involved in the uptake mechanisms. Hypnum transplants showed elemental contents generally higher than R. pseudoacacia leaves, despite the shorter exposure time. Moss accumulated larger amounts of elements linked to PM and the resuspension of soil dust. Based on the calculation of deposition flux for each element, R. pseudoacacia showed lower values for most elements—except Cr, Mo and Zn—indicating that uptake takes place both by deposition on the leaf surface and absorption via the root. Leaf traits (micromorphology of surface) play an important role in the interception and retention of PM-linked elements. Hypnum transplanted in bags was confirmed to be a powerful bio-accumulator of airborne elements; by contrast, R. pseudoacacia, with a smooth surface and scarce trichomes, showed a limited ability in airborne element retention. Therefore, widely diffused species, well-adapted to anthropized environments, such as black locust, not always can be considered as good biomonitors. The results are discussed in comparison to other vascular plant species used in biomonitoring studies.

Testing a novel biotechnological passive sampler for monitoring atmospheric PAH pollution

In this study we evaluated a new type of passive air sampler, the "mossphere" device, filled with a Sphagnum palustre clone. For this purpose, we compared the atmospheric levels of polyaromatic hydrocarbons (PAHs) collected using this device and those collected in conventional bulk deposition and particulate matter (PM10) samplers. All three types of samplers were exposed at 10 sites affected by different levels of pollution and located in two different climate zones. The bulk deposition/ mossphere comparison yielded a greater number of significant regressions with higher coefficients of determination than the PM10/ mossphere comparison. No significant regressions were observed for 3-ring PAHs in either comparison. The mosspheres explain ca. 50% of the variability of the concentrations of 4-, 5- and 6-ring PAHs and total PAHs detected in PM10 and ca. 70% of the corresponding concentrations detected in the bulk deposition. The use of the Sphagnum clone enables standardization of the set-up, thus making the mossphere device a good sampling tool for monitoring 4-, 5- and 6-ring and total PAHs, especially those associated with bulk deposition. The findings indicate the potential usefulness of this innovative technology for mapping PAH levels.

Biosurface properties and lead adsorption in a clone of Sphagnum palustre (Mosses): Towards a unified protocol of biomonitoring of airborne heavy metal pollution

Although mosses are widely used for active biomonitoring of air pollution, a unified protocol for their treatment before exposure in bags is still lacking. Here we used field- and laboratory-grown Sphagnum palustre L. moss, respectively, treated by EDTA and devitalized by oven drying at 100 °C, to elaborate a consistent procedure of metal and proton adsorption on moss surfaces. Acid-base titrations and Pb²⁺ adsorption experiments at different pH values and Pb²⁺ concentrations in solution were performed with both field-collected and laboratory cloned mosses. Devitalization and EDTA treatments did not produce any measurable difference in terms of H⁺ and Pb²⁺ adsorption capacities of moss surfaces. The stability constants for Pb²⁺ adsorption onto moss surfaces as a function of pH (pH-dependent adsorption edge) and at constant pH (5.5 and 6.5) as a function of Pb²⁺ concentration ("langmuirian" adsorption isotherm) were rather similar between different treatments. A Linear Program Modeling (LPM) of adsorption reactions revealed high similarity of adsorption constants regardless of treatments for both field-grown and cloned mosses. Therefore, in view of the use of S. palustre clone for biomonitoring lead in the environment, we recommend devitalization at 100 °C as unique treatment to perform with the aim to preserve the biomonitor before and after its exposure in bags.

Indoor vs. outdoor airborne element array: A novel approach using moss bags to explore possible pollution sources

This study investigated by the moss-bag approach the pattern of air dispersed elements in 12 coupled indoor/outdoor exposure sites, all located in urban and rural residential areas. The aims were to discriminate indoor vs. outdoor element composition in coupled exposure sites and find possible relation between moss elemental profile and specific characteristics of each exposure site. Elements were considered enriched when in 60% of the sites, post-exposure concentration exceeded pre-exposure concentration plus two folds the standard deviation. Of the 53 analyzed elements, 15 (As, B, Ca, Co, Cr, Cu, Mn, Mo, Ni, Sb, Se, Sn, Sr, V, Zn) were enriched in moss exposed outdoor, whereas a subset of 7 elements (As, B, Cr, Mo, Ni, Se, V) were enriched also in indoor moss samples. The cluster analysis of the sites based on all elements, clearly separated samples in two groups corresponding to mosses exposed indoor and outdoor, with the latter generally exceeding the first. Among outdoor sites, urban were most impacted than rural; whereas other factors (e.g., heating and cooking systems, building material, residence time and family life style) could affect element profile of indoor environments. Based on the indoor/outdoor ratio, As derived from outdoor and indoor sources, B, Mo and Se were enriched mostly in outdoor sites; Ni, Cr and V were specifically enriched in most indoor samples, supporting the presence of indoor emitting sources for these elements. A PCA of all indoor sites based on enriched elements and site characteristics showed that traffic affected indoor pollution in urban areas. The moss bag approach provided useful information for a global assessment of human exposure.

Background element content in the lichen Pseudevernia furfuracea: a comparative analysis of digestion methods

In bioaccumulation studies, the interpretation of pollutant contents in the target biomonitor has to be performed by assessing a deviation from an unaltered reference condition. A common strategy consists in the comparison with background element content (BEC) values, often built up by uncritically merging methodologically heterogeneous data. In this respect, the acid digestion of samples was identified as a major step affecting BEC data. Here, the analytical outcomes of two acid mixtures were compared on a set of matched paired samples of the lichen Pseudevernia furfuracea, a widely used biomonitor for which BEC values based on partial digestion were previously provided. The standard reference material BCR 482 (P. furfuracea) was used to validate analytical procedures consisting of either a HF total mineralization or an aqua regia partial one, both associated to ICP-MS multi-element analysis. In particular, the performance of the procedures was evaluated by comparing analytical results of field samples with the accuracy obtained on BCR aliquots (measured-to-expected percentage ratio). The total digestion showed a better performance for Al, As, Ba, Ca, Cd, Cu, Fe, Mn, Ni, Se, Sn, and Zn, whereas the opposite was found for Cr, Co, P, and S. Moreover, new BEC values were provided for P. furfuracea using a consolidated statistical approach, after a total sample digestion with hydrofluoric acid. The multivariate investigation of the background variability of 43 elements in 57 remote Italian sites led to the identification of geographically homogeneous areas for which BEC values are provided for use as reference in biomonitoring applications.

(Persistent) Organic pollutants in Germany: results from a pilot study within the 2015 moss survey

BACKGROUND

Since 1990, every 5 years, moss sampling is conducted within the European moss monitoring programme to assess the atmospheric deposition of airborne pollutants. Besides many other countries, Germany takes regularly part at these evaluations. Within the European moss monitoring 2015, more than 400 moss samples across Germany were taken according to a harmonized methodology for the assessment heavy metal and nitrogen input. In a pilot programme, eight of these sites were chosen for additional investigations on a broad range of organic contaminants to evaluate their accumulation in moss and thereby their presence in atmospheric deposition in Germany. Target compound classes comprised polycyclic aromatic hydrocarbons (PAH), polychlorinated dibenzodioxins and -furans (PCDD/F), dioxin-like and non-dioxin-like polychlorinated biphenyls (dl-PCB, ndl-PCB), polyfluorinated alkyl substances, classical flame retardants as well as emerging chlorinated and brominated flame retardants. In total, 120 target compounds were analysed. For some analytes, comparisons of accumulation in moss and tree leave samples were possible.

RESULTS

Except for certain flame retardants, PFAS, and ndl-PCB, substances of all other compound classes could be quantified in moss samples of all sites. Concentrations were highest for PAH (40-268 ng g-1) followed by emerging flame retardants (0.5-7.7 ng g-1), polybrominated diphenyl ethers (PBDE; 0.3-3.7 ng g-1), hexabromocyclododecane (HBCD; 0.3-1.2 ng g-1), dl-PCB (0.04-0.4 ng g-1) and PCDD/F (0.008-0.06 ng g-1).

CONCLUSIONS

Results show the widespread atmospheric distribution and deposition of organic contaminants across Germany as well as the suitability of moss as bioaccumulation monitor for most of these compound classes. Compared to nearby tree leaf samples, accumulation potential of moss appeared to be higher for pollutants of high octanol-air partition coefficient (KOA) and octanol-water partition coefficient (KOW).

Stability of mercury concentration measurements in archived soil and peat samples

Archived soil samples can provide important information on the history of environmental contamination and by comparison with recently collected samples, temporal trends can be inferred. Little previous work has addressed whether mercury (Hg) concentrations in soil samples are stable with long-term storage under standard laboratory conditions. In this study, we have re-analyzed using cold vapor atomic absorption spectroscopy a set of archived soil samples that ranged from relatively pristine mountainous sites to a polluted site near a non-ferrous metal smelter with a wide range of Hg concentrations (6.7-6485 μg kg^-1). Samples included organic and mineral soils and peats with a carbon content that ranged from 0.2 to 47.7%. Soil samples were stored in polyethylene bags or bottles and held in laboratory rooms where temperature was not kept to a constant value. Mercury concentrations in four subsets of samples were originally measured in 2000, 2005, 2006 and 2007, and re-analyzed in 2017, i.e. after 17, 12, 11 and 10 years of storage. Statistical analyses of either separated or lumped data yielded no significant differences between the original and current Hg concentrations. Based on these analyses, we show that archived soil and peat samples can be used to evaluate historical soil mercury contamination.

Background element content of the lichen Pseudevernia furfuracea: A supra-national state of art implemented by novel field data from Italy

In biomonitoring, the knowledge of background element content (BEC) values is an essential pre-requisite for the correct assessment of pollution levels. Here, we estimated the BEC values of a highly performing biomonitor, the epiphytic lichen Pseudevernia furfuracea, by means of a careful review of literature data, integrated by an extensive field survey. Methodologically homogeneous element content datasets, reflecting different exposure conditions across European and extra-European countries, were compiled and comparatively analysed. Element content in samples collected in remote areas was compared to that of potentially enriched samples, testing differences between medians for 25 elements. This analysis confirmed that the former samples were substantially unaffected by anthropogenic contributions, and their metrics were therefore proposed as a first overview at supra-national background level. We also showed that bioaccumulation studies suffer a huge methodological variability. Limited to original field data, we investigated the background variability of 43 elements in 62 remote Italian sites, characterized in GIS environment for anthropization, land use, climate and lithology at different scale resolution. The relationships between selected environmental descriptors and BEC were tested using Principal Component Regression (PCR) modelling. Elemental composition resulted significantly dependent on land use, climate and lithology. In the case of lithogenic elements, regression models correctly reproduced the lichen content throughout the country at randomly selected sites. Further descriptors should be identified only for As, Co, and V. Through a multivariate approach we also identified three geographically homogeneous macro-regions for which specific BECs were provided for use as reference in biomonitoring applications.

Monitoring Heavy Metal Contents with Sphagnum Junghuhnianum Moss Bags in Relation to Traffic Volume in Wuxi, China

Despite its small size, a moss bag can reveal the different temporal and spatial deposition patterns of pollutants at a particular site; therefore, researchers can use moss bags to determine pollution sources and to put forward strategies for pollution control. Although the use of moss bags to monitor atmospheric pollution has been widely reported in Europe, there are few such empirical studies in China. Thus, in this study, bags containing the moss Sphagnum junghuhnianum were used to assess the concentrations of heavy metals (chromium (Cr), copper (Cu), lead (Pb), vanadium (V), and zinc (Zn)) at five sampling sites (four roads and a forest park) during the summer and winter of 2012. According to the relative accumulation factor (RAF) and contamination factor (CF) results, pollution in winter was heavier than that in summer, and Cr was found to be the most contaminating, having the highest mean CF. There was a significant positive correlation (p < 0.05) between traffic volume and concentration for three heavy metals (Cr, Cu, and V) in winter, whereas a significant positive correlation (p < 0.05) was observed between traffic volume and concentrations for four heavy metal elements (Cr, Pb, V, and Zn) in summer, indicating a close relationship between heavy metal contents and traffic volume. Although there was substantial variation in the concentrations of the five heavy metals in the moss bags, significant correlations between heavy metals suggested that the contaminants originated from a common source, namely vehicle emissions. The results demonstrated that the four roads were subject to different degrees of pollution depending on the volume of traffic using each road. Therefore, the results of this study suggest that traffic volume is a major reason for heavy metal pollution.

Land use and air quality in urban environments: Human health risk assessment due to inhalation of airborne particles

Particle matter (PM) and its associated compounds are a serious problem for urban air quality and a threat to human health. In the present study, we assessed the intraurban variation of PM, and characterized the human health risk associated to the inhalation of particles measured on PM filters, considering different land use areas in the urban area of Cordoba city (Argentina) and different age groups. To assess the intraurban variation of PM, a biomonitoring network of T. capillaris was established in 15 sampling sites with different land use and the bioaccumulation of Co, Cu, Fe, Mn, Ni, Pb and Zn was quantified. After that, particles were collected by instrumental monitors placed at the most representative sampling sites of each land use category and an inhalation risk was calculated. A remarkable intraurban difference in the heavy metals content measured in the biomonitors was observed, in relation with the sampling site land use. The higher content was detected at industrial areas as well as in sites with intense vehicular traffic. Mean PM₁₀ levels exceeded the standard suggested by the U.S. EPA in all land use areas, except for the downtown. Hazard Index values were below EPA's safe limit in all land use areas and in the different age groups. In contrast, the carcinogenic risk analysis showed that all urban areas exceeded the acceptable limit (1 × 10^-6), while the industrial sampling sites and the elder group presented a carcinogenic risk higher that the unacceptable limit. These findings validate the use of T. capillaris to assess intraurban air quality and also show there is an important intraurban variation in human health risk associated to different land use.

Biomagnetic monitoring and element content of lichen transplants in a mixed land use area of NE Italy

The aim of this study was to verify whether it is possible to discriminate between the different pollution sources present in a mixed land use area of NE Italy on the basis of the magnetic properties and the element content of lichen transplants. Thalli of Pseudevernia furfuracea were collected in a pristine area of the South-Eastern Alps and exposed for 2months in 40 sites located at the knots of a 700m step grid covering ca. 40km² of a mosaic of agricultural, forested, industrial and urban areas. In this way, the samples could be analyzed after a defined period of time, and compared to pre-exposure conditions. The post-exposure element content and the magnetic data substantially agreed, revealing a rather modest anthropogenic impact on the territory, mostly limited to an industrial park. Since the magnetic mineralogy was homogeneous throughout the entire set of samples, with magnetite-like minerals as the main magnetic carriers, it was not possible to discriminate between PM originating from the different pollution sources. The contribution given by the industrial park could be confirmed by the multivariate analysis of the element data set. Conversely, it was possible to assess the low environmental impact of the largest local industry, a cement plant, located outside the industrial park. Notwithstanding the relatively short time of the survey, P. furfuracea was proven to be an effective accumulator for biomagnetic monitoring studies, its magnetic properties being excellent proxies for heavy metal pollution even when the anthropogenic impact on the territory is low.

Biomagnetic Monitoring of Atmospheric Pollution: A Review of Magnetic Signatures from Biological Sensors

Biomagnetic monitoring of atmospheric pollution is a growing application in the field of environmental magnetism. Particulate matter (PM) in atmospheric pollution contains readily measurable concentrations of magnetic minerals. Biological surfaces, exposed to atmospheric pollution, accumulate magnetic particles over time, providing a record of location-specific, time-integrated air quality information. This review summarizes current knowledge of biological material ("sensors") used for biomagnetic monitoring purposes. Our work addresses the following: the range of magnetic properties reported for lichens, mosses, leaves, bark, trunk wood, insects, crustaceans, mammal and human tissues; their associations with atmospheric pollutant species (PM, NO_x, trace elements, PAHs); the pros and cons of biomagnetic monitoring of atmospheric pollution; current challenges for large-scale implementation of biomagnetic monitoring; and future perspectives. A summary table is presented, with the aim of aiding researchers and policy makers in selecting the most suitable biological sensor for their intended biomagnetic monitoring purpose.

Sphagnum palustre clone vs native Pseudoscleropodium purum: A first trial in the field to validate the future of the moss bag technique

Although a large body of literature exists on the use of transplanted mosses for biomonitoring of air pollution, no article has addressed so far the use and the accumulation performance of a cloned moss for this purpose. In this work, a direct comparison of metal accumulation between bags filled with a Sphagnum palustre L. clone or with native Pseudoscleropodium purum Hedw., one of the most used moss species in biomonitoring surveys, was investigated. The test was performed in sites with different atmospheric contamination levels selected in urban, industrial, agricultural and background areas of Italy and Spain. Among the eighteen elements investigated, S. palustre was significantly enriched in 10 elements (Al, Ba, Cr, Cu, Fe, Hg, Pb, Sr, V and Zn), while P. purum was enriched only in 6 elements (Al, Ba, Cu, Hg, Pb and Sr), and had a consistently lower uptake capacity than S. palustre. The clone proved to be more sensitive in terms of metal uptake and showed a better performance as a bioaccumulator, providing a higher accumulation signal and allowing a finer distinction among the different land uses and levels of pollution. The excellent uptake performance of the S. palustre clone compared to the native P. purum and its low and stable baseline elemental content, evidenced in this work, are key features for the improvement of the moss bag approach and its large scale application.

Atmospheric particulate matter intercepted by moss-bags: Relations to moss trace element uptake and land use

Particulate matter has to be constantly monitored because it is an important atmospheric transport form of potentially harmful contaminants. The cost-effective method of the moss-bags can be employed to evaluate both loads and chemical composition of PM. PM entrapped by the moss Pseudoscleropodium purum exposed in bags in 9 European sites was characterized for number, size and chemical composition by SEM/EDX. Moreover, moss elemental uptake of 53 elements including rare earth elements was estimated by ICP-MS analysis. All above was aimed to find possible relations between PM profile and moss uptake and to find out eventual element markers of the different land use (i.e. agricultural, urban, industrial) of the selected sites. After exposure, about 12,000 particles, mostly within the inhalable fraction, were counted on P. purum leaves; their number generally increased from the agricultural sites to the urban and industrial ones. ICP analysis indicated that twenty-three elements were significantly accumulated by mosses with different element profile according to the various land uses. The PM from agricultural sites were mainly made of natural/crustal elements or derived from rural activities. Industrial-related PM covered a wider range of sources, from those linked to specific industrial activities, to those related to manufacturing processes or use of heavy-duty vehicles. This study indicates a close association between PM amount and moss element-uptake, which increases in parallel with PM amount. Precious metals and REEs may constitute novel markers of air pollution in urban and agricultural sites, respectively.

Biomonitoring of heavy metals contamination by mosses and lichens around Slovinky tailing pond (Slovakia)

Three moss (Pleurozium spp., Polytrichum spp., and Rhytidiadelphus spp.) and two lichen (Hypogymnia physodes and Pseudevernia furfuracea) taxons covered in the bags were used to monitor air quality. Bags were exposed at the different distances from the tailing pond because of insufficient security and source of heavy metal pollution. Moss/lichen bags were exposed for six weeks at 0-, 50-, 100-, 150- and 200-m distances from Slovinky tailing pond, in the main wind direction (down the valley). Accumulation ability of heavy metals expressed by relative accumulation factor (RAF) increases in the order of Polytrichum spp.<H. physodes <Pleurozium spp.<P. furfuracea <Rhytidiadelphus spp. Moss/lichen species showed different accumulation capacity for individual heavy metals. Rhytidiadelphus spp. was found to possess the significantly highest (P < 0.01) ability to accumulate Cd, Zn, Ni, Mn and Fe. The highest RAF values of Pb, Zn, Ni and Fe were determined in samples exposed at 200-m distance from pollution source.

Tracking the route of phenanthrene uptake in mosses: An experimental trial

In recent decades, mosses have been used as native species or as transplants in monitoring a wide range of pollutants from inorganic (i.e. metals and metalloids) to organic contaminants (mainly polycyclic aromatic hydrocarbons-PAHs). To implement the use of mosses as biomonitors of PAHs, one important issue is the study of the interactions between these compounds and moss tissues. In this study we investigated the mode of phenanthrene uptake in four moss species (Amblystegium humile, Plagiomnium affine, Hypnum cupressiforme and a clone of Sphagnum palustre) and its movements from air to plant surface and within the biomonitors, using fluorescent and confocal microscopy. The target compound, partitioned between gas and particulate phase depending on air conditions, was selected since it is one of the most abundant PAHs released into the atmosphere. Our findings support the hypothesis that phenanthrene aggregates in particles and in this form it is chiefly intercepted and uptaken onto moss surfaces, albeit with different frequency in the four species, with S. palustre>H. cupressiforme>P. affine=A. humile. Phenanthrene enters the dead, empty hyalocysts of S. palustre. Specific surface area and composition, frequency and distribution of binding groups may also explain the different ability of phenanthrene uptake by the four moss species.