Heavy metal and nitrogen concentrations in mosses are declining across Europe whilst some "hotspots" remain in 2010

A review of 210Pb and 210Po in moss

Among environment contaminants, 210Pb and 210Po have gained significant research attention due to their radioactive toxicity. Moss, with its exceptional adsorption capability for these radionuclides, serves as an indicator for environmental 210Pb and 210Po pollution. The paper reviews a total of 138 articles, summarizing the common methods and analytical results of 210Pb and 210Po research in moss. It elucidates the accumulation characteristics of 210Pb and 210Po in moss, discusses current research challenges, potential solutions, and future prospects in this field. Existing literature indicates limitations in common measurement techniques for 210Pb and 210Po in moss, characterized by high detection limits or lengthy sample processing. The concentration of 210Pb and 210Po within moss display substantial variations across different regions worldwide, ranging from Collapse

Key Words

• (210)Pb
• (210)Po
• Environmental contamination
• Measurement method
• Moss bioindication

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MESH Headings

• Lead Radioisotopes/analysis
• Polonium/analysis
• Bryophyta/chemistry
• Radiation Monitoring/methods

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Grants Collapse

Affiliation(s)

Chenlu Ding College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Qiang Yang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China; Sichuan Cancer Hospital & Institute, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 611731, PR China.
Xue Zhao Chongqing Radiation Environment Supervision and Management Station, Chongqing, 400015, PR China
Lipeng Xu Sichuan Cancer Hospital & Institute, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 611731, PR China
Hui Tang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China; Sichuan Management and Monitoring Center Station of Radioactive Environment, Chengdu, 611139, PR China
Zhengshang Liu College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Juan Zhai College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Qingxian Zhang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China

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Assessing heavy metal contamination in a Brazilian metropolis: a case study with a focus on (bio)indicators

The continuous expansion of the global vehicle fleet poses a growing threat to environmental quality through heavy metal contamination. In this scenario, monitoring to safeguard public health in urban areas is necessary. Our study involved the collection of 36 street dust and 29 moss samples from roads of a Brazilian metropolis (Recife) with varying traffic intensities as follows: natural reserve (0 vehicles per day), low (< 15,000 vehicles per day), medium (15,000-30,000 vehicles per day), and high (> 30,000 vehicles per day). ICP-AES analysis was performed to determine the concentrations of nine potentially toxic metals (Ba, Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn) to assess the influence of vehicular flow on urban contamination. In the street dust samples, the mean metal concentrations (mg kg-1) exhibited the following order: Ba (503.7) > Mn (303.0) > Zn (144.4) > Cu (95.3) > Cr (56.1) > Pb (34.2) > V (28.7) > Ni (11.3) > Cd (1.5). Conversely, in the moss samples, the metal concentration order was as follows (mg kg-1): Mn (63.8) > Zn (62.5) > Ba (61.0) > Cu (17.7) > Cr (8.0) > V (7.3) > Pb (7.0) > Ni (2.9) > Cd (0.3). Roads with higher traffic volumes exhibited the highest metal enrichments in moss samples for all metals and in dust samples for Cd, Cr, Mn, Ni, and V. However, dust from low-flow roads had higher enrichments for Ba, Cu, and Zn, indicating the influential role of other traffic-related factors in metal deposition. Our findings highlight traffic flow as the predominant source of pollution in urban centers, with both street dust and moss serving as sensitive indicators of metal input attributable to vehicular traffic. These indicators offer valuable insights for urban quality monitoring and pollution control efforts.

Regional air quality study by assessing trace metal atmospheric deposition

This study addresses the atmospheric deposition of trace elements investigated in Albania, Croatia and Macedonia in 2010 as part of the European Moss Study. This study provides data on the concentration of ten metals (Cd, Cr, Cu, Ni, Pb, V, Zn, Fe, Al, and Li) in naturally growing mosses. In general, all concentration data follow a lognormal distribution. Cd, Cr, Ni, and Zn show strong fluctuations in the moss samples from Albania and Macedonia, and Pb, Fe, and Al in the mosses from Croatia. The concentrations of Cd, Cu, and Zn were higher in the samples from Croatia than in those from Albania and Macedonia; the concentrations of Cr, Ni, V, Fe, Al, and Li were higher in the samples from Albania than in those from Croatia and Macedonia; and a higher concentration of Pb was found in the samples from Macedonia. The observed relationship between the concentration of lithogenic elements (Al, Fe, and V) and the air quality index (AQI) confirms that moss species have a high capacity to retain atmospheric deposition particles. The anthropogenic emission sources of these elements from local and long-range transport were considered to be the most important factors affecting air quality in the studied areas.

Estimating atmospheric nitrogen deposition within a large river basin using moss nitrogen and isotope signatures

Assessing flux and primary sources of the atmospheric nitrogen (N) deposition with high spatial resolution remained challenging. The epilithic moss is considered a suitable biological monitor to explore N deposition. Our study presented a detailed analysis of flux and major source contributions of ammonium (NH4+) and nitrate (NO3-) deposition using N and δ15N signatures of epilithic moss collected densely from the Yangtze River basin. The results showed a more negative δ15N and higher N concentration of the moss in cropland and urban area than in forest and grassland of the basin. A gradient of the estimated N deposition (9.6-34.0 kg ha-1 yr-1) occurred from the Tibetan Plateau to lower reaches, with amount of NH4+ was approximately three times higher than NO3- deposition. The contribution from volatilization to NH4+ deposition (33.28 ± 8.10%) was less than the contribution from combustion (66.72 ± 8.10%), inconsistent with the traditional findings that N fertilizer and livestock waste are the principal sources of NH3 emissions. Fossil fuel was the dominant sources of NO3- deposition, accounted for 70.22 ± 18.67%. From 2006 to 2019, the source contribution of N deposition in forest remained unchanged, while NH3 volatilization and fossil fuel emitted NOx in urban areas have increased. Our findings highlighted the importance of combustion sources to N deposition in the Yangtze River basin.

Decreased atmospheric deposition of heavy metals in Latvia shown by long-term monitoring using the moss Pleurozium schreberi

In Europe, economic restructuring and technological progress has been aimed at reducing pollution emissions at local, regional and global scales, which has been monitored using standard methods. Among the many methods used to determine deposition of heavy metals, in Europe moss has been used to monitor atmospheric pollution for more than 30 years on a 5-year cycle. This simple method can be used to assess improvement to the environment after massive economic change. Using PCA analysis, this study examines the long-term trends of heavy metal concentrations (Cr, Cu, Ni, Pb, V, Zn) in Latvia. There has been a decline in heavy metal concentrations in Latvia related to the closure of large industries after the collapse of the Soviet Union and due to change in fossil fuels in the energy sector from petroleum to natural gas, but past effect from some sources is still evident. Increased quality of automobile fuel led to a decrease of lead concentration, and conversion of fuel source in the energy sector from oil to natural gas caused a decline of V and Ni concentration.

Spatial distribution and source analysis of airborne trace metal deposition using moss biomonitoring in Huai'an, China

Terrestrial mosses are tracers for studying atmospheric trace metal deposition and pollution. Here, Al, Fe, Zn, Mn, Ba, Cu, V, Cr, Pb, Ni, Co, and Cd concentrations in mosses from Huai'an, China, were measured to investigate their contamination level, spatial distribution, and sources. The average concentration of all the metals (except Ni) was much higher than those in Albania, a "hotspot" of toxic metal contamination in Europe. The pollution degree of the metals varied significantly: moderate contamination by Al, Fe, Mn, Zn, Cr, V, and Cd; slight contamination by Ba, Cu, Ni, and Pb; and suspected contamination by Co. Based on the Nemerow index (P_N), only 8% of the moss samples were graded as moderate pollution, while the remaining 92% were rated as heavy pollution, with Cd and Zn contributing the most. The potential ecological risk index (RI) indicated a moderate potential ecological risk from the metals in Huai'an, with the atmosphere most heavily polluted by Cd. Further, the positive matrix factorization (PMF) model was applied to confirm the metal contamination sources and allocate their source contributions in Huai'an mosses. The results showed that the source contributions of industrial activities related to metal smelting, textile dyestuff and agricultural activities, mining development, natural source, and coal burning and traffic emission accounted for 28.86%, 20.29%, 19.83%, 17.98%, and 13.04%, respectively.

Global ambient air quality monitoring: Can mosses help? A systematic meta-analysis of literature about passive moss biomonitoring

Surging incidents of air quality-related public health hazards, and environmental degradation, have prompted the global authorities to seek newer avenues of air quality monitoring, especially in developing economies, where the situation appears most alarming besides difficulties around 'adequate' deployment of air quality sensors. In the present narrative, we adopt a systematic review methodology (PRISMA, Preferred Reporting Items for Systematic reviews and Meta-Analyses) around recent global literature (2002-2022), around moss-based passive biomonitoring approaches which might offer the regulatory authorities a complementary means to fill 'gaps' in existing air quality records. Following the 4-phased search procedure under PRISMA, total of 123 documents were selected for review. A wealth of research demonstrates how passive biomonitoring, with strategic use of mosses, could become an invaluable regulatory (and research) tool to monitor atmospheric deposition patterns and help identifying the main drivers of air quality changes (e.g., anthropogenic and/or natural). Besides individual studies, we briefly reflect on the European Moss Survey, underway since 1990, which aptly showcases mosses as 'naturally occurring' sensors of ambient air quality for a slew of metals (heavy and trace) and persistent organic pollutants, and help assessing spatio-temporal changes therein. To that end, we urge the global research community to conduct targeted research around various pollutant uptake mechanisms by mosses (e.g., species-specific interactions, environmental conditions, land management practices). Of late, mosses have found various environmental applications as well, such as in epidemiological investigations, identification of pollutant sources and transport mechanisms, assessment of air quality in diverse and complex urban ecosystems, and even detecting short-term changes in ambient air quality (e.g., COVID-19 Lockdown), each being critical for the authorities to develop informed and strategic regulatory measures. To that end, we review current literature and highlight to the regulatory authorities how to extend moss-based observations, by integrating them with a wide range of ecological indicators to assess regional environmental vulnerability/risk due to degrading air quality. Overall, an underlying motive behind this narrative was to broaden the current regulatory outlook and purview, to bolster and diversify existing air quality monitoring initiatives, by coupling the moss-based outputs with the traditional, sensor-based datasets, and attain improved spatial representation. However, we also make a strong case of conducting more targeted research to fill in the 'gaps' in our current understanding of moss-based passive biomonitoring details, with increased case studies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10668-023-03043-0.

Biomonitoring of Airborne Microplastic Deposition in Semi-Natural and Rural Sites Using the Moss Hypnum cupressiforme

We show that the native moss Hypnum cupressiforme can be used as a biomonitor of atmospheric microplastics (MPs). The moss was collected in seven semi-natural and rural sites in Campania (southern Italy) and was analyzed for the presence of MPs, according to standard protocols. Moss samples from all sites accumulated MPs, with fibers representing the largest fraction of plastic debris. Higher numbers of MPs and longer fibers were recorded in moss samples from sites closer to urbanized areas, likely as the results of a continuous flux from sources. The MP size class distribution showed that small size classes characterized sites having a lower level of MP deposition and a high altitude above sea level.

Accumulation of antimony and lead in leaves and needles of trees: The role of traffic emissions

Antimony (Sb) is a toxic metalloid, which has been increasingly used in the brake lining of vehicles, and increased concentrations have been found in soils near abundant traffic. However, since very few investigations of Sb accumulation in urban vegetation have been undertaken there exists a knowledge gap. We studied the concentrations of Sb in leaves and needles of trees in the Gothenburg City area, Sweden. In addition, lead (Pb), also associated with traffic, was investigated. Sb and Pb concentrations of Quercus palustris leaves at seven sites with contrasting traffic intensity varied substantially, correlated with the traffic-related PAH (polycyclic aromatic hydrocarbon) air pollution at the sites and increased during the growing season. Sb but not Pb concentrations were significantly higher in needles of Picea abies and Pinus sylvestris near major roads compared to sites at larger distances. In Pinus nigra needles at two urban streets both Sb and Pb were higher compared to an urban nature park environment, emphasising the role of traffic emissions for these elements. A continued accumulation of Sb and Pb in three years old needles of Pinus nigra, two years old needles of Pinus sylvestris and eleven years old needles of Picea abies was observed. Our data suggest a pronounced link between traffic pollution and Sb accumulation in leaves and needles, where the particles carrying Sb seem not to be transported very far from the source. We also conclude that there exists a strong potential for Sb and Pb bioaccumulation over time in leaves and needles. Implications of these findings are that increased concentrations of toxic Sb and Pb are likely to prevail in environments with high traffic intensity and that Sb can enter the ecological food chain by accumulation in leaves and needles, which is important for the biogeochemical cycling.

Moss Bags as Biomonitors of Atmospheric Microplastic Deposition in Urban Environments

Microplastics (plastic particles <5 mm) were first identified in the environment during the 1970s and have since become ubiquitous across every environmental compartment. However, few studies have focused on atmospheric microplastics, and even fewer have used biological monitoring to assess their atmospheric deposition. Here, we assess the efficacy of moss bags as an active biomonitoring technique for atmospheric microplastic deposition. Moss (Pleurozium schreberi) bags were exposed in duplicate at nine deployment sites across a gradient of urban intensity in southern Ontario, Canada. A total of 186 microplastics (mp) were detected in the moss bags, resulting in a mean accumulation of 7.9 mp g^-1 dry weight moss across all sites during the exposure period (45 days). The median microplastic length was 0.56 mm (range 0.03-4.51 mm), and the dominant microplastic type was fibres (47%), followed by fragments (39%). Microplastic accumulation significantly increased with urban intensity, ranging from 3.7 mp g^-1 in low-density suburban areas to 10.7 mp g^-1 in densely populated and trafficked urban areas. In contrast, microfibres by proportion dominated in suburban (62%) compared with urban areas (33%). Microplastic deposition was estimated to range from 21 to 60 mp m^-2 day^-1 across the nine deployment sites. The results suggest that moss bags may be a suitable technique for the active biomonitoring of atmospheric microplastic deposition in urban environments.

Moss biomonitoring of air pollution with potentially toxic elements in the Kumanovo Region, North Macedonia

A study was carried out to investigate air deposition and to explore the natural distribution and contamination with potentially toxic elements (PTEs) in the Kumanovo Region, North Macedonia, by using moss samples as biomonitors for air pollution. The distribution of 51 elements was detected in 42 moss samples collected from this area. Moss samples were analyzed following microwave digestion by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). It was found that the atmospheric deposition for some PTEs in the moss samples in specific parts of the study area is influenced by anthropogenic and urban activities. R-mode factor analysis was used to identify and characterize element associations, and six associations of elements were determined. Four factors were separated from the group of macroelements determined by ICP-AES: Factor 1 (Al, Cr, Fe, Li, Ni, V, and Zn), F2 (K, Mg, and P), F3 (Ba and Sr), and F4 (Cd, Pb, and Zn); and two associations were separated from the group of trace elements determined by ICP-MS: Factor 1 (As, Co, Cs, Ga, Ge, Sc, Ti, Y, Zr, and rare earth elements-REEs) and Factor 2 (Bi, Br, Hg, I, Sb, Sn, and W).

A review on moss nitrogen and isotope signatures evidence for atmospheric nitrogen deposition

Moss nitrogen (N) concentration and isotopic composition (δ¹⁵N) values can reveal a better understanding of atmospheric N deposition patterns. Here, we summarize the moss N content and δ¹⁵N signatures using data compiled from 104 papers. Based on the dataset, we summarize the models for assessing the level and reduced (NH_x): oxidised compounds (NO_x) ratio of atmospheric N deposition. Results showed a historical increase in N concentration and ¹⁵N depletion of specimen mosses close to anthropogenic N sources from intensive animal production and agricultural activities (NH_x emission) since the 1800s. However, an increase of moss N with a less negative ¹⁵N observed in the last three decades could be due to a substantial fossil fuel combustion contributed NO_x emission. Spatially, N deposition in Europe decreased due to successful control actions, but Asia has become a hotspot for NH_x emission from agriculture. The present results highlight the importance of moss N and δ¹⁵N values for estimating atmospheric N deposition patterns at spatio-temporal trends.

Biomonitoring of transboundary pollutants using moss in Japan's mountains

Long-range transported atmospheric pollutants (or transboundary pollutants) include trace metals with isotope ratios and compositions that vary from those of domestic pollutants, which threaten mountain ecosystems. These differences can be applied as indices to evaluate the influence of transboundary pollutants on mountain ecosystems. Mosses play important ecological functions in mountains and are sensitive to atmospheric deposition. Therefore, using these indices for moss biomonitoring can provide a more accurate indication of ecosystem health. However, studies on indices that are appropriate for moss biomonitoring are limited. Here, the effectiveness of moss biomonitoring using trace metal indices was examined to evaluate transboundary pollutants in mountainous areas in Japan. Transboundary pollutants in these areas originate from mainland Asia and are characterized by high lead isotope ratios, lead-to-zinc (Pb/Zn) ratios, and arsenic-to-vanadium (As/V) ratios. Given that the abundance of transboundary pollutants decreases with distance from mainland Asia, these three indices are also expected to vary with distance. The Pb isotope ratios were found to decrease with distance from mainland Asia; in contrast, the Pb/Zn and As/V ratios did not display any notable relationship with distance. These results are likely attributed to biological and environmental factors that affect trace metal content in moss. Thus, moss Pb isotope ratios are useful indicators of transboundary pollutants in Japan's mountains, offering an important tool for comparable moss biomonitoring studies in East Asia.

Selecting Biomonitors of Atmospheric Nitrogen Deposition: Guidelines for Practitioners and Decision Makers

Environmental pollution is a major threat to public health and is the cause of important economic losses worldwide. Atmospheric nitrogen deposition is one of the most significant components of environmental pollution, which, in addition to being a health risk, is one of the leading drivers of global biodiversity loss. However, monitoring pollution is not possible in many regions of the world because the instrumentation, deployment, operation, and maintenance of automated systems is onerous. An affordable alternative is the use of biomonitors, naturally occurring or transplanted organisms that respond to environmental pollution with a consistent and measurable ecophysiological response. This policy brief advocates for the use of biomonitors of atmospheric nitrogen deposition. Descriptions of the biological and monitoring particularities of commonly utilized biomonitor lichens, bryophytes, vascular epiphytes, herbs, and woody plants, are followed by a discussion of the principal ecophysiological parameters that have been shown to respond to the different nitrogen emissions and their rate of deposition.

The impact of childhood lead exposure on adult personality: Evidence from the United States, Europe, and a large-scale natural experiment

Childhood lead exposure has devastating lifelong consequences, as even low-level exposure stunts intelligence and leads to delinquent behavior. However, these consequences may be more extensive than previously thought because childhood lead exposure may adversely affect normal-range personality traits. Personality influences nearly every aspect of human functioning, from well-being to career earnings to longevity, so effects of lead exposure on personality would have far-reaching societal consequences. In a preregistered investigation, we tested this hypothesis by linking historic atmospheric lead data from 269 US counties and 37 European nations to personality questionnaire data from over 1.5 million people who grew up in these areas. Adjusting for age and socioeconomic status, US adults who grew up in counties with higher atmospheric lead levels had less adaptive personality profiles: they were less agreeable and conscientious and, among younger participants, more neurotic. Next, we utilized a natural experiment, the removal of leaded gasoline because of the 1970 Clean Air Act, to test whether lead exposure caused these personality differences. Participants born after atmospheric lead levels began to decline in their county had more mature, psychologically healthy adult personalities (higher agreeableness and conscientiousness and lower neuroticism), but these findings were not discriminable from pure cohort effects. Finally, we replicated associations in Europeans. European participants who spent their childhood in areas with more atmospheric lead were less agreeable and more neurotic in adulthood. Our findings suggest that further reduction of lead exposure is a critical public health issue.

A Review of Metal Levels in Urban Dust, Their Methods of Determination, and Risk Assessment

This review gives insights into the levels of metals in urban dust, their determination methods, and risk assessment. Urban dust harbors a number of pollutants, including heavy metals. There are various methods used for the sampling of urban dust for heavy-metal analysis and source-apportionment purposes, with the predominant one being the use of plastic sampling materials to avoid prior contamination. There are also various methods for the determination of metals, which include: atomic absorption spectroscopy (AAS) and inductively coupled plasma-mass spectrometry (ICP-MS), among others. Studies have shown that pollutants in urban dust are mainly derived from industrial activities and coal combustion, whereas traffic emissions are also an important, but not a predominant source of pollution. The varying particle-size distribution of urban dust and its large surface area makes it easier for the deposition and transport of heavy metals. Risk-assessment studies have shown that metals in urban dust could cause such problems as human pulmonary toxicity and reduction of invertebrate populations. The risk levels seem to be higher in children than adults, as some studies have shown. It is therefore important that studies on metals in urban dust should always incorporate risk assessment as one of the main issues.

The Pedosphere as a Sink, Source, and Record of Anthropogenic and Natural Arsenic Atmospheric Deposition

The Anthropocene has led to global-scale contamination of the biosphere through diffuse atmospheric dispersal of arsenic. This review considers the sources arsenic to soils and its subsequent fate, identifying key knowledge gaps. There is a particular focus on soil classification and stratigraphy, as this is central to the topic under consideration. For Europe and North America, peat core chrono-sequences record massive enhancement of arsenic depositional flux from the onset of the Industrial Revolution to the late 20th century, while modern mitigation efforts have led to a sharp decline in emissions. Recent arsenic wet and dry depositional flux measurements and modern ice core records suggest that it is South America and East Asia that are now primary global-scale polluters. Natural sources of arsenic to the atmosphere are primarily from volcanic emissions, aeolian soil dust entrainment, and microbial biomethylation. However, quantifying these natural inputs to the atmosphere, and subsequent redeposition to soils, is only starting to become better defined. The pedosphere acts as both a sink and source of deposited arsenic. Soil is highly heterogeneous in the natural arsenic already present, in the chemical and biological regulation of its mobility within soil horizons, and in interaction with climatic and geomorphological settings. Mineral soils tend to be an arsenic sink, while organic soils act as both a sink and a source. It is identified here that peatlands hold a considerable amount of Anthropocene released arsenic, and that this store can be potentially remobilized under climate change scenarios. Also, increased ambient temperature seems to cause enhanced arsine release from soils, and potentially also from the oceans, leading to enhanced rates of arsenic biogeochemical cycling through the atmosphere. With respect to agriculture, rice cultivation was identified as a particular concern in Southeast Asia due to the current high arsenic deposition rates to soil, the efficiency of arsenic assimilation by rice grain, and grain yield reduction through toxicity.

Source and spatial distribution of airborne heavy metal deposition studied using mosses as biomonitors in Yancheng, China

Naturally growing mosses have been successfully used as biomonitors of atmospheric heavy metal (HM) deposition. In recent years, with rapid economic development, environmental pollution in Yancheng, a coastal city in central Jiangsu Province, China, has become increasingly serious. However, to date, there have been no reports on atmospheric HM deposition in Yancheng. In this study, we investigated the HM concentrations and Pb isotopes in the moss Haplocladium microphyllum (Hedw.) Broth. from Yancheng and analyzed their main sources. The concentrations of HM in mosses from Yancheng were higher than those recorded in other studies of mosses from HM smelting regions and pollution-free areas of Eurasia and Alaska. The contamination factor value suggested that the pollution level of Cd was the highest. The pollution load index indicated that the studied area was severely contaminated with Cd, Cr, Pb, Zn, V, Ni, and Cu. Positive matrix factorization was employed to identify the contamination sources of HM and apportion their source contributions in mosses. The contributions of the natural source, together with manufacturing and construction, metal processing and chemical industries, traffic emissions and fuel burning in industrial activities, and agricultural activities, accounted for 53%, 33%, 12%, and 2%, respectively. The Pb isotopic ratios in the mosses (1.125-1.164 for 206Pb/207Pb, 2.059-2.148 for 208Pb/206Pb) further proved that metal processing and traffic emissions were the main sources of Pb contamination. These results are useful for developing various effective measures to prevent and reduce atmospheric HM deposition in Yancheng.

Accelerated vegetation succession but no hydrological change in a boreal fen during 20 years of recent climate change

Northern mires (fens and bogs) have significant climate feedbacks and contribute to biodiversity, providing habitats to specialized biota. Many studies have found drying and degradation of bogs in response to climate change, while northern fens have received less attention. Rich fens are particularly important to biodiversity, but subject to global climate change, fen ecosystems may change via direct response of vegetation or indirectly by hydrological changes. With repeated sampling over the past 20 years, we aim to reveal trends in hydrology and vegetation in a pristine boreal fen with gradient from rich to poor fen and bog vegetation. We resampled 203 semi-permanent plots and compared water-table depth (WTD), pH, concentrations of mineral elements, and dissolved organic carbon (DOC), plant species occurrences, community structure, and vegetation types between 1998 and 2018. In the study area, the annual mean temperature rose by 1.0°C and precipitation by 46 mm, in 20-year periods prior to sampling occasions. We found that wet fen vegetation decreased, while bog and poor fen vegetation increased significantly. This reflected a trend of increasing abundance of common, generalist hummock species at the expense of fen specialist species. Changes were the most pronounced in high pH plots, where Sphagnum mosses had significantly increased in plot frequency, cover, and species richness. Changes of water chemistry were mainly insignificant in concentration levels and spatial patterns. Although indications toward drier conditions were found in vegetation, WTD had not consistently increased, instead, our results revealed complex dynamics of WTD as depending on vegetation changes. Overall, we found significant trend in vegetation, conforming to common succession pattern from rich to poor fen and bog vegetation. Our results suggest that responses intrinsic to vegetation, such as increased productivity or altered species interactions, may be more significant than indirect effects via local hydrology to the ecosystem response to climate warming.

Significance of the long-term biomonitoring studies for understanding the impact of pollutants on the environment based on a synthesis of 25-year biomonitoring in the Holy Cross Mountains, Poland

This review presents compiled results of complex biomonitoring studies that have been conducted in the Holy Cross Mountains, south-central part of Poland, since the 1990s. The significance of these studies results from several aspects: (i) a number and a variety of plant organisms used, e.g., mosses, lichens, coniferous and deciduous trees, and their tissues (wood, bark, needles, leaves, the aboveground parts of several vascular plants); (ii) applications of a broad scope of instrumental methods aiming at determining major and trace elements (including rare earth elements), organic compounds (PAHs, PCBs, phenols), and stable sulfur isotopes (δ³⁴S); and (iii) different methodological and environmental issues addressed. The comparison and interpretation of results derived from seventeen sampling campaigns carried out between 1994 and 2017 are a valuable source of information on the following: (i) bioaccumulative properties of organisms used in air quality monitoring, (ii) identification and variations of local and regional pollution sources and geochemical landscape patterns and processes over years, and (iii) establishing environmental factors that variously affected chemical composition of plants growing under physiological stress, including roadside vegetation and plants from acid mine drainage areas.

Lamina Cell Shape and Cell Wall Thickness Are Useful Indicators for Metal Tolerance-An Example in Bryophytes

Bryophytes are widely used to monitor air quality. Due to the lack of a cuticle, their cells can be compared to the roots of crop plants. This study aimed to test a hypothetical relation between metal tolerance and cell shape in biomonitoring mosses (Hypnum cupressiforme, Pleurozium schreberi, Pseudoscleropodium purum) and metal sensitive species (Physcomitrium patens, Plagiomnium affine). The tolerance experiments were conducted on leafy gametophytes exposed to solutions of ZnSO4, ZnCl₂, and FeSO₄ in graded concentrations of 1 M to 10⁻⁸ M. Plasmolysis in D-mannitol (0.8 M) was used as a viability measure. The selected species differed significantly in lamina cell shape, cell wall thickness, and metal tolerance. In those tested mosses, the lamina cell shape correlated significantly with the heavy metal tolerance, and we found differences for ZnSO4 and ZnCl₂. Biomonitoring species with long and thin cells proved more tolerant than species with isodiametric cells. For the latter, “death zones” at intermediate metal concentrations were found upon exposure to ZnSO4. Species with a greater tolerance towards FeSO₄ and ZnSO₄ had thicker cell walls than less tolerant species. Hence, cell shape as a protoplast-to-wall ratio, in combination with cell wall thickness, could be a good marker for metal tolerance.

Atmospheric Mercury Deposition in Macedonia from 2002 to 2015 Determined Using the Moss Biomonitoring Technique

The moss biomonitoring technique was used in 2002, 2005, 2010 and 2015 in a potentially toxic elements study (PTEs) in Macedonia. For that purpose, more than 70 moss samples from two dominant species (Hypnum cupressiforme and Homalothecium lutescens) were collected during the summers of the mentioned years. Total digestion of the samples was done using a microwave digestion system, whilst mercury was analyzed by cold vapour atomic absorption spectrometry (CV–AAS). The content of mercury ranged from 0.018 mg/kg to 0.26 mg/kg in 2002, from 0.010 mg/kg to 0.42 mg/kg in 2005, from 0.010 mg/kg to 0.60 mg/kg in 2010 and from 0.020 mg/kg to 0.25 mg/kg in 2015. Analysis of the median values shows the increase of the content in the period 2002–2010 and a slight reduction of the air pollution with Hg in the period 2010–2015. Mercury distribution maps show that sites with increased concentrations of mercury in moss are likely impacted by anthropogenic pollution. The results were compared to similar studies done during the same years in neighboring countries and in Norway—which is a pristine area and serves as a reference, and it was concluded that mercury air pollution in Macedonia is significant primarily in industrialized regions.

Decadal Changes in Trace Metal Concentrations in Upland Headwater Lakes

The objective of this study was to assess the current chemistry of trace elements in upland headwater lakes in Ireland and determine their trends during the last decade in response to decreasing emissions. Twenty-nine upland lakes were sampled in 2017-2018; 19 were previously sampled in 2007-2008. The 2017-2018 samples were analyzed for conductivity, pH, DOC, and 18 trace elements. The lakes had low element concentrations; only 7 of 18 trace elements were > 1 µg/L (Fe, Al, Zn, Mn, B, Sr and Ba). Nine elements were assessed for significant decadal changes; four elements decreased (B, Co, Mn, and Sr) and one increased (Pb). Their correlation with conductivity, pH, and DOC and the associated changes in those variables partially explained the observed trends. In general, elements that were correlated with DOC did not decrease, while those that were not correlated decreased between the two periods. Despite decreased anthropogenic emissions, ecosystem recovery and climate perturbations can confound or mask the benefits of emissions reductions.

Cadmium contents of vertically and horizontally deposited winter precipitation in Central Europe: Spatial distribution and long-term trends

Cadmium (Cd) and its forms has recently been a focus of attention due to its toxic effects on human health and the environment. We evaluated the atmospheric deposition of Cd during three consecutive winter seasons (2009-2011) at 10 mountain-top locations in the Czech Republic along the borders with Poland, Germany, Austria and Slovakia. Cadmium concentrations of soluble and insoluble forms in both horizontal (rime) and vertical (snow) deposition were determined using sector-field ICP-MS. Across the sites, 94% of the total winter Cd deposition occurred in the soluble (environmentally available) Cd form. Mean concentrations of soluble Cd in rime were six times higher than in snow (398 vs. 66 ng L^-1). Vertical deposition contributed as much as 41% to the total winter Cd input. Between-site variability in Cd deposition was large, ranging between 13 and 108 μg m^-2 winter^-1. Overall, Cd concentrations in winter deposition did not reach the drinking water limits and did not pose a direct threat for human health. Long-term trends (1996-2017) in winter Cd deposition were evaluated at six GEOMON sites (a monitoring network of small forested catchments). Since 1996, Cd input in winter atmospheric deposition decreased by 73-93%. Simultaneously, we found declines in between-site variability in winter Cd inputs. The highest recent winter Cd inputs were found at sites located in the northeast of the country. A north-south pollution gradient, which has frequently been mentioned in the literature, was not observed, with both northwestern sites and southern sites being among those with the lowest Cd pollution. Backward trajectories of the HYSPLIT model for fresh snow samples identified Poland and Germany as major transboundary Cd pollution sources for the Czech Republic.

Assessment of urban environmental quality through the measurement of lead in bryophytes: case study in a medium-sized city

The use of bryophytes as an indicator of environmental quality has been addressed on numerous occasions and in different places of the world under a variety of conditions. However, in Latin America their use is still limited. In the study described here, the presence and distribution of the bioaccumulation of lead in bryophytes has been evaluated in both contaminated and uncontaminated sites in Villavicencio (Colombia) and its surroundings. Villavicencio is a medium-sized city that is similar in size to many other cities in Latin America. A total of 52 samples of bryophytes were collected, of which 43 belong to points distributed in urban areas of the city (residential, commercial, highway), and the remaining nine are from uncontaminated areas (reference) taken in the surroundings of the city. The samples were treated with acid (nitric and hydrochloric) and subsequently measured by atomic absorption spectrometry. It was found that Pb concentrations in the commercial sector are between 1 and 6 times higher than in the residential and highway sectors. Spatial distribution maps of lead over the sampled territory were created using Arc-GIS 10.1. It is noteworthy that the values obtained are higher than those found in European cities.

Atmospheric Heavy Metal Deposition in North Macedonia from 2002 to 2010 Studied by Moss Biomonitoring Technique

Moss biomonitoring technique was used for a heavy-metal pollution study in Macedonia in the framework of the International Cooperative Program on Effects of Air Pollution on Natural Vegetation and Crops (UNECE IPC Vegetation). Moss samples (n = 72) were collected during the summers of 2002, 2005, and 2010. The contents of 41 elements were determined by neutron activation analysis, atomic absorption spectrometry, and inductively coupled plasma atomic emission spectrometry. Using factor and cluster analyses, three geogenic factors were determined (Factor 1, including Al, As, Co, Cs, Fe, Hf, Na, Rb, Sc, Ta, Th, Ti, U, V, Zr, and rare-earth elements–RE; Factor 4 with Ba, K, and Sr; and Factor 5 with Br and I), one anthropogenic factor (Factor 2, including Cd, Pb, Sb, and Zn), and one geogenic-anthropogenic factor (Factor 3, including Cr and Ni). The highest anthropogenic impact of heavy metal to the air pollution in the country was from the ferronickel smelter near Kavadraci (Ni and Cr), the lead and zinc mines in the vicinity of Makedonska Kamenica, Probištip, and Kriva Palanka in the eastern part of the country (Cd, Pb, and Zn), and the former lead and zinc smelter plant in Veles. Beside the anthropogenic influences, the lithology and the composition of the soil also play an important role in the distribution of the elements.

Copper Content and Resistance Mechanisms in the Terrestrial Moss Ptychostomum capillare: A Case Study in an Abandoned Copper Mine in Central Spain

We present a case study on the tissue absorption of copper of a widely distributed moss species, Ptychostomum capillare in the polluted soil of an abandoned copper mine in central Spain. We studied the soil properties in a copper soil pollution gradient and sampled the moss tufts growing on them in four plots with contrasted soil copper levels. We determined the copper content in the soil and in the moss tissues. On these moss samples, we also performed histochemical tests and X-ray dispersive spectrometry coupled with scanning electron microscopy (SEM-EDX), both in untreated shoots and in samples where surface waxes were removed. We checked the behavior of this species using a metallophillous moss, Scopelophila cataractae, for comparative purposes. Copper contents in P. capillare seem to depend more on available, rather than total soil copper contents. Our results indicate that this moss is able to concentrate 12-fold the available soil copper in soil with low available copper content, whereas in the most polluted soil the concentration of Cu in the moss was only half those levels. Both histochemical and SEM-EDX tests show no surface copper in the mosses from the least polluted plot, whereas in samples from the soil with highest copper content, the removal of surface waxes also reduces or removes copper from the moss shoots. Our observations point at a mixed strategy in P. capillare in this copper mine, with metal accumulation behavior in the lowest Cu plot, and an exclusion mechanism involving wax-like substances acting as a barrier in the most polluted plots. These distortions impede the estimation of environmental levels and thus compromise the value of this moss in biomonitoring. We highlight the need of extending these studies to other moss species, especially those used in biomonitoring programs.

Métaux, pollution de l’air et santé

L’exposition à long terme aux particules atmosphériques a des effets bien documentés sur la santé humaine, mais le rôle des métaux reste à explorer. En France, la réglementation impose le suivi des teneurs ambiantes de certains métaux. Mais ces données, du fait d’un maillage trop large ou irrégulier, sont difficilement exploitables en épidémiologie à grande échelle. Les mousses, des végétaux capables d’accumuler les métaux atmosphériques, sont utilisées depuis plusieurs décennies en biosurveillance de la qualité de l’air. Elles fournissent des données exploitables en épidémiologie grâce auxquelles nous avons montré une association entre métaux d’origine anthropique et sur-risque de mortalité en France.

Temporal and Cross-Regional Variability in the Level of Air Pollution in Poland—A Study Using Moss as a Bioindicator

This study assessed recent (2015) and past (2001) levels of air pollution in four regions of Poland by moss monitoring. The surveyed regions encompassed, among others, copper and zinc-lead industrial districts, large urban agglomerations and an area away from pollution sources. Moss (Pleurozium schreberi) was sampled from 117 sites. In 2001, the concentrations of Cd, Cr, Cu, Fe, Ni, Pb, and Zn were determined. In 2015, 10 extra elements were analyzed in addition to these metals. The results showed that the regions substantially differed in the chemical profile of air pollution, which corresponded well with the type of industry and the degree of industrialization and urbanization. There was also a significant change in air pollution between the 2001 and 2015 surveys, but it was inconsistent: its magnitude and direction were both metal-dependent and region-dependent. Namely, while the levels of some metals (e.g., Cd and Pb) decreased, other metals (e.g., Cr and Ni) showed the opposite trend. Importantly, these decreases (or increases) were usually limited to regions of low concentrations of a given metal. The results suggest that air quality has not significantly improved recently, but the type of emissions has changed. It seems that the importance of non-industrial pollution sources has increased.

Investigations of the Atmospheric Deposition of Major and Trace Elements in Western Tajikistan by Using the Hylocomium splendens Moss as Bioindicators

The study was performed in a mountainous area of approximately 7000 sq. km of Western Tajikistan, i.e., Turkestan, Zeravshan, Hissar, and Karateghin ridges that are characterized by complex geological settings. Moss biomonitoring was used to assess the concentration level of trace and major elements in atmospheric deposition of the study area. Hylocomium splendens (Hedw.) Schimp. moss was used as biomonitor in this study. 43 major and trace-elements were determined by Epithermal Neutron Activation (ENAA) and Atomic Absorption Spectrometry (AAS). GIS maps of the 43 elements showed that the distribution of Mo, Cd, REE, Th, and U could be most probably associated with the Odjuk pegmatite field. Zr, Hf, and W contents are significantly increased in the vicinity of the Sarbo River washout while Cr, Co, Ni, and As showed a maximum content near Kanchoch gold field. The global pollution index based on the local content of presumed pollutants Cr, Ni, Cu, Zn, As, Cd, Sb, and Pb in some places exceeded the threshold limits for a pristine, unpolluted environment. At the same time, the distribution of incompatible Sc, La, Yb, and Th suggested for the airborne material deposited on mosses a continental component, enriched in few places in felsic components.

Catchment soils as a factor of trace metal accumulation in sediments of the reservoir Klingenberg (eastern Ore Mountains, Germany)

The release and accumulation dynamics of trace metals in soils and aquatic sediments were exemplarily investigated in the catchment area of the Reservoir Klingenberg (Germany). Catchment soils were examined for mobilizable and total concentrations of arsenic (As), cadmium (Cd), chrome (Cr), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) and compared with trace metal quantities accumulated in riverbed and reservoir sediments. The comparison of all samples showed relatively small variations of Cr (7.96-46.0 mg/kg), Fe (7.79-40.4 g/kg), and Ni (6.06-56.5 mg/kg), while stronger differences were found for As (11.2-164 mg/kg), Cd (0.14-30.5 mg/kg), Mn (0.08-1.84 g/kg), Pb (20.7-183 mg/kg), and Zn (69.1-916 mg/kg). The catchment soils were slightly enriched by Cd, Pb, and Zn. Especially Cd and Zn were characterized by large mobilizable proportions. The mean trace metal concentrations in riverbed sediments were higher than in catchment soils, while reservoir sediments accumulated the highest amounts of the analyzed elements. The enrichment of trace metals in reservoir sediments was generally determined by the sedimentation of fine particles, while the distribution of As, Fe, and Mn was additionally impacted by redox conditions. For Cd and Zn, which in comparison were most enriched in riverbed and reservoir sediments, a significant release from soils by leaching processes was observed. The accumulation of As and Pb in reservoir sediments was influenced to a greater extent by soil erosion and by anthropogenic or chalcogen sources in the catchment.

Quantifying the elemental composition of mosses in western Washington USA

Major and trace element deposition across western Washington, USA was assessed in 2016 and 2017 by analyzing tissue metal concentrations in the epiphytic mosses Isothecium stoloniferum (Bridel) and Kindbergia praelonga (Hedw.) Ochyra. We used an intensive, vertically stratified sampling approach in Acer macrophyllum canopies in the Hoh Rainforest on the Olympic Peninsula, WA and in Seattle, WA to collect 214 samples of I. stoloniferum. An extensive, ground-based sampling approach was used across an urban-to-wildland gradient to collect 59 K. praelonga samples. Intensive samples were collected four times (April, July, and October of 2016 and in January 2017) and extensive samples three times (April, July, and October 2016) to assess seasonal differences in metal concentrations across sampling locations. A total of 273 moss samples were analyzed for Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, Sr, Ti, and Zn concentrations. Elevated concentrations of these elements were found in moss samples from both intensive and extensive sampling efforts across all seasons. Sampling location for both intensive and extensive sampling efforts was found to be a significant factor in determining moss metal concentrations. Metal deposition in and around Seattle appears to be derived from the regional transportation sector and other industrial sources. Ten I. stoloniferum samples from Seattle and the Hoh Rainforest were analyzed for Pb and Sr isotope ratios to help differentiate between natural and industrial-based emission sources. Hoh Rainforest Pb isotopes appear to be explained by a mixture of long-range Asian Pb influences and natural Pb sources, whereas Seattle Pb isotopes appear driven by industrial and road dust sources.

A multivariate examination of the timing and accumulation of potentially toxic elements at Las Conchas bog (NW Spain)

The inorganic content of the well-preserved 3.2-m record of Las Conchas bog (NW Spain), covering 8000 cal yr BP., was analysed. To study natural vs. human contributions, we applied an innovative approach, namely the sequential study of multivariate statistics (factor analysis followed by clustering of the factor score matrix) and enrichment factors (EFs). The increasing weight of potentially toxic elements (PTEs) such as the geochemical association of Zn, Pb and Cd (EFs higher than 10, 20 and 40 in the last two centuries) was revealed, and corroborated by the contrast between the contents of anthropogenic Pb and total Rare Earth Elements (a suitable proxy for natural geogenic supplies). Furthermore, elements such as Hg, Tl and As also showed enrichment in the most recent samples of the study core. Some of them are commonly associated with global atmospheric transport; however, in this case, their increasing contents could also be explained by nearby industrial and mining activities. In summary, severe pollution was observed in the uppermost part of the record, thereby pointing to an important environmental concern. Given that local and regional sources of PTEs, such as mining and heavy industry, especially Zn smelting, were probably the main historical causes of this contamination and that some of these industries are still active, we consider that our findings deserve further attention.

National environmental quality assessment and monitoring of atmospheric heavy metal pollution - A moss bag approach

As airborne pollution is recognised as the single largest environmental health hazard in Europe, the necessity to develop effective systems for monitoring and reducing the level of air pollutants, becomes imperative. The paper describes a tested and implemented long-term biomonitoring system for airborne heavy metals at a national scale. Moss bags (Hylocomium splendens) were exposed in 142 monitoring stations designated in Romania, and the content of Pb, Cd, Ni and As was quantified using inductively coupled plasma mass spectrometry. The results revealed that the accumulation of heavy metals exceeded the established thresholds, marking high pollution levels in 8.8% of samples for As, in 5.63% samples for Cd, in 3.17% samples for Pb, and in 0.35% samples for Ni. The maximum heavy metal concentration was 113.77 mg kg^-1 dry weight for Pb, 44.93 mg kg^-1 dry weight for Ni, 14.68 mg kg^-1 dry weight for As, and 3.88 mg kg^-1 dry weight for Cd, with several overlaps for at least two metals, thus marking pollution hotspots. In order to process, summarise and communicate the obtained data, a software named BioMonRo has been developed as the core part of a complex monitoring and warning-informative system. The software is able to generate heavy metal pollution maps and specific reports, depicting the levels and patterns of distribution, which can be automatically sent to a number of interested recipients. The results show that the developed national system is functional, cost-effective, and could be successfully used for long-term monitoring of airborne heavy metals.

Perspective of mitigating atmospheric heavy metal pollution: using mosses as biomonitoring and indicator organism

Mosses were proved as an ideal and reliable biomonitor as well as an indicator of atmospheric trace metal pollution. They are used as model indicator species of air pollution since long back due to their simple structure, genetic diversity, totipotency, rapid colony-forming ability, and high metal resistance behavior. Bryomonitoring technique is gradually being popularized as an economically viable procedure for estimating the degrees of environmental health and evaluating the toxic pollutants in biosphere. Thus, in the present scenario, many parts of the world use these organisms for monitoring the air pollution. This article describes an overview of the relationship of terrestrial mosses with trace metals with respect to their uptake, accumulation, and toxification as well as detoxification and tolerance mechanisms. The review article explicitly expresses the caliber of the cryptogamic mosses in establishing the pristine environment around the world. It also highlights the underpinning mechanisms and potential for future research directions. We have referred more than 250 articles, which deals with the assessment and impact of different heavy metals on 52 numbers of different moss species belongs to different climatic zones. The present review covers the research work in this area carried out worldwide since 1965.

Spatial distribution and pollution assessment of heavy metals in soil from the Republic of North Macedonia

The purpose of the study was to determine the spatial distribution and pollution assessment of 39 chemical elements in soil from the Republic of North Macedonia. From the whole territory of the country top soil samples (0-30 cm) were collected from 995 locations with a grid of 5 × 5 km distance between the sampling locations. Two analytical techniques were used for the analysis of soil samples: inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry. Based on a comparison of statistical parameters, spatial distribution of particular elements and results of cluster and factor analysis, four mаin geochemical associations were identified: (1) association connected with the Neogene and Quaternary volcanism (Ba, Be, Ce, Hf, K, La, Rb, Th, Tl, U and Zr); (2) association of siderophile elements (Co, Cu, Fe, Mn, Sc, Ti and V); (3) association connected with ophiolites and Mesozoic ultrabasic magmatic rocks of Vardar zone (Cr and Ni) and (4) chalcophile (sulphide) elements (As, Bi, Cd, Pb, Sb, Sn and Zn). The regional distribution was prepared according to the eight statistical regions in Macedonia, distribution according to 15 most common geological formation and distribution according to 13 pedological units.

Heavy Metal Atmospheric Deposition Study in Moscow Region, Russia

The air quality in north-eastern part of Moscow region was evaluated by trace metals atmospheric deposition using moss Pleurozium schreberi as bioindicator. Thirty six elements were determined in analyzed samples by Neutron activation analysis and Atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Maps showing the geographical distribution of the factor scores were built using ArcGis software. Median values of the elements studied were compared with data obtained for other regions in Russia. The present survey showed that industrial activity, thermal power plants and transport still have the largest anthropogenic impact on air pollution in studied region.

Long-term moss monitoring of atmospheric deposition near a large steelworks reveals the growing importance of local non-industrial sources of pollution

Although air quality in Europe is continually improving, there are regions, especially in central and eastern European countries, where this trend has been unnoticeable and even reversed in recent years. To understand the possible reasons for the persistence of these pollution "hotspots", we investigated the case of the Kraków region (S Poland) known for its heavy pollution caused by a large steelworks. In 1975, at the apogee of industrial emissions, atmospheric deposition of trace metals was evaluated in this area using moss Pleurozium schreberi as a biomonitor. The survey was repeated in 1992, 1998 and 2014. The collected data showed that air quality improved significantly over 40 years: the amount of Cd, Pb, Fe, Cu and Zn accumulated by mosses decreased by a factor of 10, 9, 3.5, 2 and 2, respectively. The downward trend continued for most metals throughout the study period, although the biggest changes occurred at the very beginning (1975-1992). This improvement was mostly due to drops in industrial production and the introduction of environmentally friendly technologies. At the end of the study (1998-2014), clear increases in the concentrations of some trace metals in moss were observed (overall or at some locations). Spatiotemporal variability of moss elemental composition suggests that this is the result of the recent emergence of new (non-industrial) sources of metal pollution, associated with the urban sprawl and intensification of agriculture. Since this process is unlikely to stop in the near future, air quality will deteriorate rather than improve.

Mercury isotopic compositions of mosses, conifer needles, and surface soils: Implications for mercury distribution and sources in Shergyla Mountain, Tibetan Plateau

Understanding the distribution and sources of mercury (Hg) in the Tibetan Plateau is of great value to study the long-range transport of Hg. Herein, the total Hg (THg) concentrations and the isotopic compositions of mosses, conifer needles, and surface soils collected from both slopes of the Shergyla Mountain of Tibetan Plateau were analyzed. The contents of THg in samples (except mosses on the eastern slope) were significantly positively correlated with altitude in both the western and eastern slopes, possibly caused by topographic factors. In contrast, Δ¹⁹⁹Hg in samples was significantly negatively correlated with altitude. On the basis of Hg isotopic compositions, atmospheric Hg⁰ uptake was indicated as the primary accumulation pathway of Hg in mosses (Δ¹⁹⁹Hg: -0.12 ± 0.09‰, -0.26 - 0.00‰, 1 SD, n = 10) and conifer needles (Δ¹⁹⁹Hg: -0.21 ± 0.08‰, -0.36 - -0.11‰, 1 SD, n = 9). Moreover, the contributing fractions of atmospheric Hg⁰ to Hg in surface soils (Δ¹⁹⁹Hg: -0.20 ± 0.07‰, -0.31 - -0.06‰, 1 SD, n = 17) increased with altitude and accounted for an average of 87 ± 9% in atmospheric sources. Due to the special geographic positions and environmental conditions of the Tibetan Plateau, the results of this study were essential for further understanding the long-range transport and global cycling of Hg.

Cadmium concentrations in German soybeans are elevated in conurbations and in regions dominated by mining and the metal industry

BACKGROUND

Cadmium (Cd) is a mobile heavy metal and soybeans accumulate more of this element compared to other grain crops. Because vegan and vegetarian lifestyles are increasingly popular, plant-based diets should be free from contaminants. Cd minimization has recently been identified as a breeding aim in addition to protein and oil levels. It is also important to consider the regional variability of Cd in crops.

RESULTS

A large sample collection (n = 602) was subjected to Cd analyses. Soybeans were grown using a standard protocol by private gardeners in a citizen science program. Some 12.5% of samples exceeded European Union limits, although Cd concentrations and exceedances showed regional variation around the national mean (0.13 mg kg-1 ). Contamination was higher in densely populated regions, possibly as a result of the long-term emissions of heavy metal loaded dusts from industry, traffic and energy production. Cd concentrations were also elevated in regions once characterized by mining and heavy industry. Values were low overall in rural areas and agricultural regions despite potential inputs via phosphate fertilizers.

CONCLUSION

Grain Cd levels are highly variable across Germany. Soybean farming may be problematic in regions with a long history of mining and heavy metal deposition. © 2018 Society of Chemical Industry.

The Evaluation of Air Quality in Albania by Moss Biomonitoring and Metals Atmospheric Deposition

The air quality of Albania is evaluated by trace metals atmospheric deposition using moss biomonitoring method. Bryophyte moss (Hypnum cupressiforme Hedw.) samples were collected during August and September 2015 from 55 sampling points distributed over the entire territory of Albania. The concentrations of Cr, Cu, Fe, Ni, Pb, V, and Zn in moss samples was determined by ICP-AES, ETAAS (As and Cd), and CVAAS (Hg) analysis. Spatial distribution and temporal trend of the moss elements is discussed in this study. Different variability was found in moss metal concentrations that may reflect their spatial distribution patterns and may identify the location of the areas with high contamination of each element. Compared with the measurements of moss collected in 2010, significant differences were found in the concentrations of As, Cr, Cu, Hg, Ni, Pb, and Zn. The differences between two moss surveys may reflect changes in the bioavailability of the elements resulting from wet and dry deposition respectively during 2015 and 2010 moss biomonitoring survey. The pollution loading index that was applied to judge the content of metal contamination indicated moderate pollution throughout Albania. Examination of the potential ecological risk found that As, Cd, Cr, Hg, Ni, and Pb pose the highest potential ecological risks particularly in the areas with high metal contents. Factor analysis applied to investigate the probable sources of metals in the environment suggested that Al and Fe likely originated from natural sources. As, Cd, Hg, Pb, Cu, Zn, Ni, and Cr likely originated from anthropogenic sources associated with long-range transport, transboundary pollution and local emission sources.

The impact of urban pollution on metal contamination of selected forest pockets in Cape Town, South Africa

Urban forests are exposed to metals, such as manganese, copper, and zinc in the atmosphere that originate from anthropogenic activities, that include vehicle-related traffic, industries, construction sites, fossil fuel burning for heating and cooking purposes, and resuspension processes related to urban surfaces. Not only is the rich biodiversity of plant and animal species in forests under threat, but so are the biodiversity of soil, sustaining ecosystem functions, as well as human health. The objective of this study was therefore to determine the concentrations of manganese, copper, and zinc arising from urban, industrial, and traffic-related pollution in the remote and/or untouched urban indigenous forests using soil, leaf litter, and key forest organisms (mosses, lichens, and millipedes) in three forests (Platbos, Orange Kloof, and Newlands) in the Western Cape, South Africa. Elevated concentrations of these metals were found in the forests closest to the city, as well as at sites in close proximity of vehicle traffic.

Interspecies comparison of three moss species (Hylocomium splendens, Pleurozium schreberi, and Isothecium stoloniferum) as biomonitors of trace element deposition

Biomonitoring with mosses is a common method widely used to assess the spatial and temporal trends of atmospheric deposition in Europe since its introduction in the 1970s. Based on previous investigations, certain moss species provide the most accurate reflection of atmospheric deposition. However, sampling of just one species across large areas can pose a challenge, therefore the ability to use multiple moss species interchangeably is integral to an effective moss biomonitoring survey. In this study, biomonitoring abilities of two common species (Hylocomium splendens [Hs] and Pleurozium schreberi [Ps]) were compared to a potential new biomonitoring species endemic to North America (Isothecium stoloniferum [Is]). Thirteen metal concentrations were analyzed (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, and Pb) in moss tissue from 20 sites with co-located species (Ps/Hs, Is/Hs) Five metals (Al, V, Fe, Ni, and Pb) showed significant and strong correlations (Spearman correlation, r ≥ 0.7 α = 0.05) for all three species, reflecting the established deposition gradient in the region. Furthermore, there was no significant difference in observations (and moderate correlation) for Cr, which suggests that all species exhibited similar uptake abilities for these six metals (Al, V, Cr, Fe, Ni, and Pb). Four metals (Co, As, Se, and Cd) exhibited concentrations below detection at a number of sites, which may have influenced the assessment of interspecies relationships. It is recommended that interspecies calibration be carried out under all surveys that employ multiple moss species.

Determination of iron species, including biomineralized jarosite, in the iron-hyperaccumulator moss Scopelophila ligulata by Mössbauer, X-ray diffraction, and elemental analyses

Scopelophila ligulata is an Fe-hyperaccumulator moss growing in acidic environments, but the mechanism of Fe accumulation remains unknown. To understand the mechanism, we determined Fe species in S. ligulata samples. The moss samples were collected from four sites in Japan. The concentrations of Fe, P, S, Cl, and K in them were measured by induced coupled plasma mass spectrometry. Fe species in some of them were determined by Mössbauer spectroscopy and were confirmed by X-ray diffraction analysis. Fe species in S. ligulata samples were determined to be jarosite, ferritin, high-spin Fe(II) species, and akaganeite. To our knowledge, this is the first report on the biomineralization of jarosite in mosses. This result, combined with the fact that bacteria, a fungus, and a grass mineralize jarosite, suggests that its biomineralization is a common characteristic in a wide variety of living organisms. These findings indicate that the biomineralization of jarosite occurs not only in the region-specific species but in species adapted to a low-pH and metal-contaminated environment in different regions, provide a better understanding of the mechanism of Fe accumulation in the Fe-hyperaccumulator moss S. ligulata, and offer new insights into the biomineralization of jarosite.

Multi-element composition of soil, mosses and mushrooms and assessment of natural and artificial radioactivity of a pristine temperate rainforest system (Slavonia, Croatia)

This study investigates multi-element composition of soil, mosses and mushrooms from a pristine temperate rainforest (Prašnik, Croatia). Additionally, the activity levels of natural (²³⁸U, ²³⁵U and ²³²Th decay chains, ⁴⁰K and ⁷Be) and anthropogenic (¹³⁷Cs and ¹³⁴Cs) radionuclides in the investigated soil samples, obtained by gamma spectrometry, provide baseline of environmental radioactivity levels in this area. The aim of investigation was to explore the uptake of metal(loid)s by bioindicator species (mosses, mushrooms) growing in a pristine environment characterized by naturally elevated concentration of metals. The calculated enrichment and bioaccumulation factors, correlations between different groups of elements and similar multi-element patterns in mosses, mushrooms and soil samples revealed the prevailing influence of the local substrate geochemistry on element concentrations in mosses and mushrooms. The results suggest atmospheric deposition of Bi, Cd and Pb, while radionuclide activities point to atmospheric fall-out (including global contamination by radiocaesium) and influence of the pedological substrate. The confined area of investigation, with limited variations in soil characteristics and geological composition, allowed clearer insight into the origin of metal(loid)s in mosses and mushrooms. On the other hand, using bioindicator species with different element uptake mechanisms enabled distinction between different sources of elements.