Do mosses exist outside of Europe? A biomonitoring reflection

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

Collapse

MESH Headings

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

Collapse

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

Collapse

One year of active moss biomonitoring in the identification of PAHs in an urbanized area-prospects and implications

Classical monitoring of air pollution provides information on environmental quality but involves high costs. An alternative to this method is the use of bioindicators. The purpose of our work was to evaluate atmospheric aerosol pollution by selected polycyclic aromatic hydrocarbons conducted as part of annual active biomonitoring ("moss-bag" technique) with the use of three moss species: Pleurozium schreberi, Sphagnum fallax, and Dicranum polysetum. The gas chromatography-mass spectrometry (GC-MS) was utilized to determine certain 13 polycyclic aromatic hydrocarbons (PAHs). Three seasonal variations in PAH concentrations have been observed as a result of the study. A fire on the toilet paper plant caused an increase of five new compounds: benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP), indeno(1.2.3)-cd_pyrene (IP), dibenzo(a.h)anthracene (Dah), and benzo(g.h.i)perylene (Bghi) in proximity after 8 months of exposure compared to previous months. The effect of meteorological conditions on the deposition of PAHs (mainly wind direction) in mosses was confirmed by principal component analysis (PCA). Dicranum polysetum moss accumulated on average 26.5% more PAHs than the other species, which allows considering its broader use in active biomonitoring. The "moss-bag" technique demonstrates its feasibility in assessing the source of PAH air pollution in a long-term study. It is recommended to use this biological method as a valuable tool in air quality monitoring.

What potential do mosses have as biomonitors of POPs? A comparative study of hexachlorocyclohexane sorption

Persistent organic pollutants (POPs) pose a significant global threat to human health and the environment, and require continuous monitoring due to their ability to migrate long distances. Active biomonitoring using cloned mosses is an inexpensive but underexplored method to assess POPs, mainly due to the poor understanding of the loading mechanisms of these pollutants in mosses. In this work, Fontinalis antipyretica (aquatic moss) and Sphagnum palustre (terrestrial moss) were evaluated as potential biomonitors of hexachlorocyclohexanes (HCHs: α-, β-, γ-, δ-HCH), crucial POPs. Moss clones, grown in photobioreactors and subsequently oven-dried, were used. Their lipid composition and distribution were characterized through molecular and histochemical studies. Adsorption experiments were carried out in the aqueous phase using the repeated additions method and in the gas phase using an active air sampling technique based on solid-phase extraction, a pioneering approach in moss research. F. antipyretica exhibited greater lipid content in the walls of most cells and higher adsorption capacity for all HCH isomers in both gaseous and liquid environments. These findings highlight the need for further investigation of POP loading mechanisms in mosses and open the door to explore other species based on their lipid content.

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.

Looking at moss through the bioeconomy lens: biomonitoring, bioaccumulation, and bioenergy potential

The field of bioeconomy has been experiencing a surge in interest in recent years as society increasingly recognizes the potential of utilizing renewable biological resources to create sustainable solutions for economic growth, resource management, and environmental protection. Despite its potential, there is a notable lack of studies exploring the utilization of moss as a viable resource within the bioeconomy framework. Aligned with this objective, this paper conducts a keyword analysis using the VOSviewer application to explore the applicability of mosses as a bioeconomy resource. While biomonitoring using mosses has been studied extensively, this paper shifts its focus to discuss advancements in this area. Moreover, it evaluates the viability of moss utilization for bioenergy production and concisely summarizes their application in microbial fuel cells. The review also highlights challenges pertinent to moss utilization and presents future prospects. The overarching goal of this review paper is to assess the potential and utilization prospects of mosses within the realms of bioaccumulation, air purification, and bioenergy. By offering a comprehensive summary of moss applications, performance, and viability across diverse sectors, this paper endeavors to promote the versatile application of mosses in various contexts. It repositions the discussion on mosses, accentuating their utilization potential prior to exploring conclusions and future prospects.

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.

Establishment of background pollution levels and spatial analysis of moss data on a regional scale

The determination of background pollution levels is fundamental for the interpretation of the results obtained from environmental biomonitoring. In this paper we propose a new probabilistic method, based on a Gaussian mixture model, for determining the distribution of regional background levels of different pollutants. The distribution of the reference level is used to categorize the observations as "background" or "above-background" and spatial statistical techniques are then applied to determine the probability of the background level being exceeded. To exemplify its use, we applied the method to concentrations of five potentially toxic elements (Cd, Cu, Hg, Pb and Zn) measured in the moss Pseudoscleropodium purum. The proposed method was applied to data resulting from sampling at ca. 150 sampling stations in a regular grid (15 × 15 km) in Galicia (NW Spain). Sampling was carried out in June in 2000 and 2002, and in March and September in 2004, 2006, 2008 and 2014. The proposed method yielded consistent results for all of the different sampling surveys, and the pollution levels were found to be closely related to the sources of pollution identified in the study region. In short, although not an optimal solution, the proposed method seems to be suitable and realistic for the qualitative assessment of regional pollution.

Comparison of Exposure Techniques and Vitality Assessment of Mosses in Active Biomonitoring for Their Suitability in Assessing Heavy Metal Pollution in Atmospheric Aerosol

The most widespread and used technique is the moss-bag method in active biomonitoring of air pollution using mosses. In the literature, we can find various studies on the standardization of this method, including attempts to standardize treatments and preparation procedures for their universal application. Few works comprehensively focus on other methods or compare other techniques used in active biomonitoring with mosses, especially including measurements of their vital parameters. Our experiment aimed to assess air pollution by selected heavy metals (Cu, Zn, Cd, Pb, Mn, Fe, and Hg) using three moss species (Pleurozium schreberi, Sphagnum fallax, and Dicranum polysetum) during a 12-week exposure in an urban area. Mosses were exposed simultaneously using four techniques: moss bag in three variants (exposed to air for total deposition of heavy metals, exposed to air for only dry deposition, and sheltered from the wind) and transplants in boxes. Increases in heavy metal concentrations in mosses were determined using the relative accumulation factor (RAF). The actual quantum yield of photosystem II photochemical was also analyzed as the main vitality parameter. The results indicate that all moss species during the changing environmental conditions survived and retained their vitality, although it decreased by >50% during the exposure. The best biomonitor was the moss P. schreberi, whose RAF increments were the highest throughout the study period for the majority of elements. The moss-bag technique had a statistically significant effect (almost 40%) on the concentration value of a given metal for a certain species, and thus it is the most recommended technique that can be applied in air quality monitoring in urban areas. Environ Toxicol Chem 2022;41:1429-1438. © 2022 SETAC.

Effects of tobacco smoke on indoor air quality: the use of mosses in biomonitoring

This research was carried out to assess the possibility of using Pleurozium schreberi mosses as bioindicators of atmospheric aerosol pollution in living quarters (kitchen and bedroom), with metals originating from tobacco smoke from various types of cigarettes: conventional cigarettes, e-cigarettes and heated tobacco products. The moss-bag method of active biomonitoring was used. The mosses were exposed in these indoor spaces for three months and, after the exposition period, their analytes - Ni, Cu, Zn, Cd and Pb - were determined using flame atomic absorption spectrometry (F-AAS). Results were interpreted using the relative accumulation factors (RAF), coefficients of variation (CV) and the Wilcoxon test. As a result of the research, it was found that there were statistically significant differences in Zn and Cd concentrations in tobacco smoke from different types of cigarettes. The analyses showed that heated tobacco products contaminate indoor air with metals, similar to conventional cigarettes and e-cigarettes. It was demonstrated that the reliability of biomonitoring results was affected, for example, by the method of preparation of bioindicator samples, such as mosses.

Is Active Moss Biomonitoring Comparable to Air Filter Standard Sampling?

Recently, significant attention has been paid to air quality awareness and its impact on human health, especially in urban agglomerations. Many types of dust samplers for air quality monitoring are used by governmental environmental monitoring agencies. However, these techniques are associated with high costs; as a consequence, biological methods such as active moss biomonitoring are being developed. The main disadvantages of such techniques are the lack of standardization of the preparation procedures and the lack of reliable comparisons of results with data from instrumental analyses. Our study aimed to compare the results obtained from active biomonitoring with the use of three moss species: Pleurozium schreberi, Sphagnum fallax and Dicranum polysetum. Samples were exposed via the moss-bag technique to measure the concentrations of analytes (Mn, Fe, Cu, Zn, Cd, Hg and Pb) which had accumulated among the total suspended particulates (TSP) collected from the filters of a dust collector in the city of Opole (Opole voivodeship, Poland). With regard to the physicochemical and biological traits of the mosses, their assessed lifetime and actual photochemical efficiency (yield) following exposure were meagre, which may have been related to the change of environment and their exposure to pollutants. When comparing the results obtained by the two methods used to monitor air pollution, the biomonitoring method was found to be incompletely consistent with the reference method. Biological monitoring using mosses must be carefully considered depending on the monitoring objectives, the required level of sensitivity and quality of measurement and the type of pollutant.

Is Your Moss Alive during Active Biomonitoring Study?

Biomonitoring was proposed to assess the condition of living organisms or entire ecosystems with the use of bioindicators-species sensitive to specific pollutants. It is important that the bioindicator species remains alive for as long as possible while retaining the ability to react to the negative effects of pollution (elimination/neutralization of hazardous contaminants). The purpose of the study was to assess the survival of Pleurozium schreberi moss during exposure (moss-bag technique) based on the measurement of the concentration of elements (Ni, Cu, Zn, Cd, and Pb), chlorophyll content, and its fluorescence. The study was carried out using a CCM-300 portable chlorophyll content meter, portable fluorometer, UV-Vis spectrophotometer, and a flame atomic absorption spectrometer. As a result of the laboratory tests, no significant differences were found in the chlorophyll content in the gametophytes of mosses tested immediately after collection from the forest, compared to those drying at room temperature in the laboratory (p = 0.175 for Student's t-test results). Mosses exposed using the moss-bag technique of active biomonitoring were characterized by a drop in the chlorophyll content over 12 weeks (more than 50% and 60% for chlorophyll-a and chlorophyll-b, respectively). Chlorophyll content in mosses during exposure was correlated with actual photochemical efficiency (yield) of photosystem II (calculated value of Pearson's linear correlation coefficient was 0.94-there was a significant correlation between chlorophyll a and yield p = 0.02). The highest metal increases in mosses (RAF values) were observed for zinc, lead, and copper after the second and third month of exposure. The article demonstrates that the moss exposed in an urbanized area for a period of three months maintains the properties of good bioindicator of environmental quality.

Testing different methods of estimating edaphic inputs in moss biomonitoring

Although soil is known to contribute to the concentrations of elements in moss, protocols for atmospheric biomonitoring with terrestrial moss do not include recommendations on how to address this factor. As a result, researchers indiscriminately use a wide range of detection/correction methods without considering whether the results are equivalent. In this study, three of these methods were compared: i) use of the enrichment factor (EF) index; ii) calculation of the ratios of different elements in soil and moss, and subtraction of the contribution of soil concentrations from the raw concentrations of elements in mosses (SCS); and iii) positive matrix factorization (PMF), a receptor modelling method for source apportioning based on multivariate analysis techniques. The aim of the comparison was to determine whether the methods produce equivalent results and, if not, which method is the most appropriate for use in moss biomonitoring surveys. The data used corresponded to 146 samples of Pseudoscleropodium purum collected from a regular sampling grid of 15 × 15 km in Galicia (NW Spain). Comparison of the methods revealed that, although they yield relatively similar results, the corresponding interpretations are not equivalent and none of the methods provides a reliable estimate of the soil contribution to the concentrations of elements in moss samples. Independently of the technique applied, use of Ti as a reference element is not recommended, because, at least in this study, it was present at unusually high levels in moss. Given the absence of a reliable correction method and the fact that most elements are present in fairly high amounts in the soil, we recommend using atmospheric biomonitoring with moss only for Cu, Zn and Cd, i.e. for those elements in moss for which the soil contributes very low amounts and corrections are not therefore necessary.

The influence of preparation methodology on the concentrations of heavy metals in Pleurozium schreberi moss samples prior to use in active biomonitoring studies

Active biomonitoring is used to assess environmental pollution of elements such as heavy metals by indicator species such as mosses. They are used, among others, in urbanized areas where no indicator species are found. In such study areas, mosses collected from sites considered to be ecologically clean shall be exposed. In this context, it is very important to prepare the mosses properly before the exposure, so that the information received about the condition of the environment is reliable. In 2018, studies were conducted in the forested areas of southern Poland-in Opolskie Province. Pleurozium schreberi mosses were used in these studies. Atomic absorption spectrometry with flame atomiser (F-AAS) was used to determine the concentrations of Mn, Fe, Ni, Cu, Zn and Pb present. The aim was to study the influence of preparation methodology on Pleurozium schreberi moss samples prior to use in active biomonitoring studies. Four different methodologies were tested across four different sample locations (with varying levels of pollution). The results of the research were analysed and the coefficient of variation (CV) was determined. The value of the CV is influenced, among other things, by the location of the particular sample and the level of pollution by, for example heavy metals, in the moss. The research conducted proves that of the four methods used to prepare mosses for later exposure in active biomonitoring, the best method is averaging with simultaneous conditioning of mosses in demineralised water. This treatment causes the CV coefficient to fall below 10% for most of the metals determined in the moss samples. It has also been shown that maintaining moss collection methodology in accordance with ICP Vegetation standards (open/wooded area-tree canopy) also has a significant impact on the result obtained. Statistical analysis confirmed (Wilcoxon test) that the method of processing the mosses significantly influenced the results obtained. Thanks to the appropriate preparation of the mosses before exposition, they can be used in active biomonitoring of, for example, urban areas.

Accumulation of natural radionuclides (7Be, 210Pb) and micro-elements in mosses, lichens and cedar and larch needles in the Arctic Western Siberia

This is a study of the atmospheric-origin natural radionuclides (⁷Be and ²¹⁰Pb) and a wide range of micro- and macro-element accumulation in mosses, lichens, cedar and larch needles in Arctic western Siberia (Yamal-Nenets Autonomous District). Based on the specific activities measurements of atmospheric precipitation markers (⁷Be and ²¹⁰Pb), this study found that the concentration of dust particles in the studied objects incrementally increases in the following order, from lowest concentration to highest: cedar needles, larch needles, lichens and mosses. Concentrations of Zr, Hf, Ti, Th, Fe, V, Li, Na, Si, Be, Y, rare earth elements (REE) and Sc in this area also increase in the same ascending sequence. Enrichment factors of these elements (EF) relative to the North American Shale Composite (NASC) are close to unity, which proves their terrigenous origin. Also, the terrigenous origin of the elements in the studied biological objects is confirmed by their high correlation coefficients with Sc. This means that their concentration in the studied biological objects is the result of a background of solid atmospheric precipitation. Enrichment factors of biogenic elements and their analogues (P, Se, Mn, Mg, Ca, K, Zn, Sr, Ba, Rb, Cs) are significantly greater than unity, and this is associated with high concentrations of these elements in the biological part of the samples. A radially symmetric distribution of Pb content in biological objects is observed over the surface of the studied area (with a center located within the city of Novy Urengoy). This leads to the conclusion that there is a point source around which anthropogenic precipitation of Pb takes place. This distribution is most clearly manifested by the example of larch and cedar needles. Anthropogenic deposition of other elements has not been detected in this study area.

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.

Distribution of radionuclides in moss-lichen cover and needles on the same grounds of landscape-climatic zones of Siberia

The radiation status of the landscape and climatic zones of Siberia at the turn of the 20th and 21st centuries is characterized using bioindicators/biomonitors: lichens, mosses, and needles, according to the results obtained at the sites of their joint growth. The maximal activity of ¹³⁷Cs in these components is observed in the forest-tundra landscaped zone, polluted during the period of nuclear tests from the nuclear test site "Novaya Zemlya" and also due to slow migration of these elements to the soil under the arctic conditions. In the southern territories the specific activity of radiocesium in the moss-lichen cover and needles of conifers corresponds to the regional background, in the forest-tundra zone it sometimes exceeds it, but in general does not pose a threat to human health. Determined differences in the contents of radioactive elements in lichens and mosses that grow together on sites in different landscape zones of Siberia statistically not significant within one or two standard deviations, and recorded only in the range of 3ϭ at the level of significance 0.05. Specificity of radionuclide distribution in lichens, mosses and needles (differences for epigeals and epiphytic lichens; different species selected at one site, annual and perennial needles, etc.) made it possible to identify the causes of variations in their activities in different zones, along with landscape features of these zones. In the needles of conifers potassium concentration exceeds the content in lichens, at lower levels of thorium and ¹³⁷Cs. The contents of uranium and thorium in the studied components in all landscape-climatic zones correspond to the natural ones, except for the single local territories, because of the possible anthropogenic influence.