The use of lichen (Cetraria nivalis) and moss (Rhacomitrium lanuginosum) as monitors for atmospheric deposition in Greenland

Spatial distribution of multi-elements in moss revealing heavy metal precipitation in London Island, Svalbard, Arctic

The Arctic is a sink for major pollutants in the Northern Hemisphere, and is an ideal place to investigate the migration of concerned metals on the local environment. In this study, 13 elements including Li, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, As, Cd, Hg, and Pb were determined in mosses (Dicranum angustum) from London Island in Ny-Ålesund. The results showed that the concentrations of different elements varied greatly at different altitudes, while their distributions in low (0-200 m) and high (200-300 m) altitudes based on cluster analysis were significantly different. Among them, Li, Ti, V, Cr, Mn, Fe, Co, Cu, and As showed significant positive correlations with elevation. This result may be due to the influence of key environmental factors such as elements transported by the airborne dust carried by winds, and surface runoff from snow meltwater. Multiple receptor models (PCA, PMF, and UNMIX) were employed to discuss the sources of metals in mosses from London Island. Elements that showed positive correlation with altitude were attributed to natural sources, and Zn, Cd, Hg, and Pb, which lacked apparent correlation with elevation, were interpreted as from anthropogenic sources by the models. Among them, Zn, Cd, and Hg were from long-range deposition, while Pb was from mixed industrial sources.

Mining pollution in Greenland - the lesson learned: A review of 50 years of environmental studies and monitoring

This review provides an overview of environmental studies and monitoring at mine sites in Greenland since the first environmental studies were conducted in the early 1970s. Mining at three legacy mine sites in Greenland (Ivittuut, Mestersvig and Maarmorilik) caused significant metal pollution, mostly with lead and zinc, due to lack of adequate environmental studies and regulation. These legacy mine sites have later served as study areas for development of methods for environmental monitoring, which can also be applied to other sites. The review describes the most significant mines in Greenland's mining history together with procedures for conducting the environmental monitoring work. A comprehensive description is provided on the research results and development of monitoring practices during the past 50 years for assessing dispersion, bioaccumulation and toxicological effects of pollutants in both the marine and terrestrial environment. Further, the current practices for sample preparation, chemical analyses and storage of samples and data are described. From the studies it is clear that monitoring needs to be site- and mine-specific, adaptive, diverse and take conditions unique to the Arctic into account, such as permafrost, seasonal drainage and fjord stratification dynamics. Based on the results, lessons learned for future monitoring programs are given. Moreover, spatial and temporal trends of the legacy pollution at the Greenland mine sites are discussed. Finally, it is shown how research and monitoring results have been applied to regulate mining activities in Greenland to minimise the environmental impact, and some future perspectives are presented. Many of the results and conclusions in the review are considered applicable to environmental monitoring of mining and other industrial activities in other areas than Greenland, both inside and outside of the Arctic.

Spatial variation of residual total petroleum hydrocarbons and ecological risk in oilfield soils

Total petroleum hydrocarbon (TPH) pollution in oilfield soils is a worldwide environmental problem. In this study, we analysed the spatial variation of residual TPH components and the ecological risk they pose. The soils of five selected oilfields in China, across 11 degrees of latitude and 17 degrees of longitude were selected for the investigation. The results showed that the non-zonal composition of the residual TPHs in the soil was similar to the that of the crude oil input. Principal component analysis (PCA) suggested that the effect of zonal environmental factors explained 81.5% of the variability in the residual indexes of saturated and aromatic hydrocarbons. The first principal component, the soil clay and organic matter, correlated positively with the residual TPH index. The second principal component, the accumulated temperature, however, correlated negatively with the residual TPH index in the soil. Moreover, the application of the soil quality index (SoQI) and a Monte Carlo simulation for estimating the residual TPH content suggested that the ecological risk caused by residual TPHs in the soil decreased when the oilfield latitude and clay and organic matter content in the oilfield soil were lower. This study provides a basis for the assessment and monitoring of ecological risk in oilfield soils worldwide.

Spatial distribution of mercury and other potentially toxic elements using epiphytic lichens in Nova Scotia

The use of naturally occurring epiphytic lichens can be an effective tool for regional monitoring of mercury (Hg) and other potentially toxic elements (PTEs). Nova Scotia, Canada is a hotspot for mercury and other trace metal accumulation in ecosystems; partially attributed to long-range transport of air pollution. The relative contribution of local and international sources of Hg to local air in Nova Scotia is unknown. This study assessed the potential of epiphytic lichens (Usnea spp.) as passive samplers for PTE air pollution in Nova Scotia. Lichens (n = 190) collected across mainland Nova Scotia were analyzed for PTEs. Results indicate that there are 3 distinct clusters of PTEs which suggest patterns and sources for each elemental cluster. Hg was correlated with longitude and prevailing wind direction, and Hg was not significantly different in site-specific hotspot sampling nor year of sampling. Our data support the hypothesis that Hg in lichens is from historical and ongoing long-range transport and diffuse emission patterns rather than localized pollution sources. PTE concentrations were shown to have median values that are similar to other remote regions (such as the Antarctic) however the maximum values were observed to be substantially higher for some elements (e.g. lead, cadmium). This research supports the use of lichens as biomonitors and provides a baseline for future monitoring efforts to identify changes in PTE distribution in Nova Scotia with ongoing industrial activity and a changing climate.

Presence and distributions of POPS in soil, atmospheric deposition, and bioindicator samples in an industrial-agricultural area in Turkey

In this study, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were detected in the soil, lichen pine needle, and total deposition samples in the Meriç-Ergene Basin, which is one of the most important regions in terms of industrial and agricultural activities in Turkey. POP concentrations were measured in 192 samples selected to represent four seasons over a 1-year period across four different regions: an intensive industrial area, an industrial + residential area, an agricultural area, and a background area. Total PAH concentrations are found in the range of 69.6-887.6 ng/g, 74.6-1277.7 ng/g, 113.4-588.9 ng/g, and 0.00-937.8 ng/m²-day; total PCB concentrations are 9.98-62.9 ng/g, 6.8-68.1 ng/g, 11.3-32.7 ng/g, and 0.00-144.4 ng/m²-day; total OCPs concentrations are 5.9-83.2 ng/g, 7.3-85.6 ng/g, 9.9-97.1 ng/g, and 0.00-137.6 ng/m²-day respectively for soil, lichen, pine needles, and bulk samples. The data were evaluated according to pollutant groups and spatial and temporal changes. The highest PAH and PCB values were detected in lichen samples from industrial areas. The highest OCP values were detected for total deposition and soil samples and in the agricultural area. The results showed that two- to three-ring PAHs, hepta-PCBs, and cyclodienes were the most widespread pollutant groups. Statistical analyses were performed to evaluate the accumulation and indication properties of the matrices in the study for 0.05 significance level. The pollutant group in which matrices are most similar is PAHs. Total deposition samples showed the most different pattern in terms of indications, especially for PCBs. For OCP results, the concentration values obtained in soil samples were different from all other matrices. It was determined that the indication properties of the matrices identified as pollutant indicators differ markedly from the pollutant type, and this difference is at the lowest level for PAH pollutants. Graphical abstract ᅟ.

Using moss and lichens in biomonitoring of heavy-metal contamination of forest areas in southern and north-eastern Poland

In the years 2014-2016 biomonitoring studies were conducted in the forest areas of south and north-eastern Poland: the Karkonosze Mountains, the Beskidy Mountains, the Borecka Forest, the Knyszyńska Forest and the Białowieska Forest. This study used epigeic moss Pleurozium schreberi and epiphytic lichens Hypogymnia physodes. Samples were collected in spring, summer and autumn. Approximately 500 samples of moss and lichens were collected for the study. In the samples, Mn, Ni, Cu, Zn, Cd, Hg and Pb concentrations were determined. Based on the obtained results, the studied areas were ranked by extent of heavy-metal deposition: Beskidy > Karkonosze Mountains > forests of north-eastern Poland. Some seasonal changes in concentrations of metals accumulated in moss and lichens were also indicated. There was observed, i.a., an increase in Cd concentration at the beginning of the growing season, which may be related to low emissions during the heating season. Analysis of the surface distribution of deposition of metals in the studied areas showed a significant contribution of nearby territorial emissions and unidentified local emission sources. The contribution of distant emission to Zn, Hg and Pb deposition levels in the Karkonosze and Beskidy region was also indicated.

Metals in Racomitrium lanuginosum from Arctic (SW Spitsbergen, Svalbard archipelago) and alpine (Karkonosze, SW Poland) tundra

Arctic-alpine tundra habitats are very vulnerable to the input of relatively small amounts of xenobiotics, and thus their level in such areas must be carefully controlled. Therefore, we collected the terrestrial widespread moss Racomitrium lanuginosum (Hedw.) Brid. in Spitsbergen in the Arctic moss lichen tundra and, for comparison, in the Arctic-alpine tundra in the Karkonosze (SW Poland). Concentrations of the elements Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Na, Ni, Pb, V, and Zn in this species and in the parent rock material were measured. We tested the following hypothesis: R. lanuginosum from Spitsbergen contains lower metal levels than the species from the Karkonosze collected at altitudes influenced by long-range transport from former Black Triangle industry. Principal component and classification analysis (PCCA) ordination revealed that mosses of Spitsbergen were distinguished by a significantly higher Na concentration of marine spray origin and mosses of Karkonosze were distinguished by significantly higher concentrations of Cd, Cr, Cu, Fe, Hg, Li, Mn, Pb, V, and Zn probably from long-range atmospheric transport. The influence of the polar station with a waste incinerator resulted in significantly higher Co, Li, and Ni concentrations in neighbouring mosses in comparison with this species from other sites. This investigation contributes to the use of R. lanuginosum as a bioindicator for metal contamination in Arctic and alpine tundra regions characterised by severe climate habitats with a restricted number of species. This moss enables the control of pollution usually brought solely by long-range atmospheric transport in high mountains as well as in Arctic areas.

Towards improved comparability of studies addressing atmospheric concentrations of semivolatile organic compounds based on their sequestration in pine needles

Coniferous needles can be used as a passive air sampler of semivolatile organic compounds (SVOC) and an indicator of atmospheric pollution patterns and trends. There is limited information on whether different parts of the plant (e.g., foliage leaves, dwarf shoots, twig, etc.) contain different levels of SVOC. Only few studies have compared levels of SVOC surface layer of wax and to their total content in all needle tissues and what affects an uptake and distribution of SVOC. It is important to have better understanding of the extent to which sampling and sample preparation procedures affect measured levels of SVOC in pine needles and reduce comparability of data from samples processed in different ways. In the present study, we assessed an impact of various sampling and sample preparation techniques on the levels of SVOC in Pinus sylvestris needles. While the impact of various storing, washing and drying methods was not significant, presence of dwarf shoots in the sample or structural damage of needles affected the results significantly. Results show that levels of SVOC in dwarf shoots are 2-8 times higher than those in foliage leaves. Therefore, dwarf shoots must be carefully removed before foliage leaves extraction to improve comparability of results. There were different patterns in SVOC on the surface of the foliage leaves compared to the whole leaves. An uptake of these substances by the surface wax as well as their occurrence in the internal structure was of function of the physico-chemical properties of the substances (log K_ow, molar weight).

Moss and lichen biomonitoring of atmospheric mercury: A review

Long-range transport and residence time of elemental Hg (Hg°) in air promote global dispersion and deposition in remote ecosystems. Many biotic and abiotic factors contribute to the photoreduction and phytovolatilization of Hg from terrestrial ecosystems, and the assessment of deposition and volatilization fluxes is very challenging. Mosses and lichens are widespread in nature and constitute the dominant vegetation in alpine and polar ecosystems. This review surveys the results of Hg biomonitoring with cryptogams in areas with different Hg sources and deposition processes. Lichen and moss ecophysiology, and factors affecting Hg uptake and bioaccumulation are discussed. Although some laboratory experiments indicate a linear accumulation of Hg in cryptogams exposed to Hg°, without any significant release, in nature the Hg accumulated in cryptogams is in a dynamic equilibrium with Hg in air and decreases when organisms are transplanted to clean environments. Mercury concentrations in mosses and lichens have often been used to estimate concentrations and deposition fluxes of atmospheric Hg; however, Hg° exchanges between cryptogams and air, and the time necessary for mosses and lichens to equilibrate elemental composition with changing atmospheric chemistry, preclude reliable estimates. Biological processes of Hg uptake and exchange with air cannot be reproduced by mechanical collectors, and comparisons between Hg concentrations in biomonitors and those in atmospheric deposition are scarcely reliable. However, the Hg biomonitoring with mosses and lichens is easy and cheap and allows to locate "hot spots" of natural or anthropogenic emissions and to assess spatio-temporal changes in Hg deposition patterns. Climate change is affecting the global Hg cycle through the melting of sea-ice in coastal Polar Regions, and modifying Hg sequestration in mountain ecosystems. Despite limitations, large-scale monitoring of Hg with mosses and lichens may be used as a tool to evaluate the impact of global processes in remote ecosystems.

Atmospheric chemistry of mercury in Antarctica and the role of cryptogams to assess deposition patterns in coastal ice-free areas

Mercury in the Antarctic troposphere has a distinct chemistry and challenging long-term measurements are needed for a better understanding of the atmospheric Hg reactions with oxidants and the exchanges of the various mercury forms among air-snow-sea and biota. Antarctic mosses and lichens are reliable biomonitors of airborne metals and in short time they can give useful information about Hg deposition patterns. Data summarized in this review show that although atmospheric Hg concentrations in the Southern Hemisphere are lower than those in the Northern Hemisphere, Antarctic cryptogams accumulate Hg at levels in the same range or higher than those observed for related cryptogam species in the Arctic, suggesting an enhanced deposition of bioavailable Hg in Antarctic coastal ice-free areas. In agreement with the newest findings in the literature, the Hg bioaccumulation in mosses and lichens from a nunatak particularly exposed to strong katabatic winds can be taken as evidence for a Hg contribution to coastal ecosystems by air masses from the Antarctic plateau. Human activities on the continent are mostly concentrated in coastal ice-free areas, and the deposition in these areas of Hg from the marine environment, the plateau and anthropogenic sources raises concern. The use of Antarctic cryptogams as biomonitors will be very useful to map Hg deposition patterns in costal ice-free areas and will contribute to a better understanding of Hg cycling in Antarctica and its environmental fate in terrestrial ecosystems.

Determination of elemental baseline using peltigeralean lichens from Northeastern Canada (Québec): Initial data collection for long term monitoring of the impact of global climate change on boreal and subarctic area in Canada

Northeastern Canada is mostly free of anthropogenic activities. The extent to which this territory has been impacted by anthropogenic atmospheric depositions remains to be studied. The main goal of our study was to establish background levels for metals in boreal muscicolous/terricolous macrolichens over non-urbanized areas of northeastern Canada (Québec). Concentrations of 18 elements (Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, and Pb) were determined for three species of the genus Peltigera (Peltigera aphthosa (L.) Willd. s.l., Peltigera neopolydactyla (Gyeln.) Gyeln. s.l., Peltigera scabrosa Th. Fr. s.l.), and Nephroma arcticum (L.) Torss., along a 1080 km south-north transect and along a of 730 km west-east transect. We report that elemental contents in the sampled lichen thalli are very low and similar to background levels found in other studies performed in pristine places (high elevation or remote ecosystems) throughout the world. Overall, our results demonstrate that most of the boreal and subarctic zone of Québec (northeastern Canada) is still pristine. The elemental baseline established in these lichen populations will contribute to monitor metal pollution in boreal and sub-polar ecosystems due to global climate change and future industrial expansion.

Importance of open marine waters to the enrichment of total mercury and monomethylmercury in lichens in the Canadian High Arctic

Caribou, which rely on lichens as forage, are a dietary source of monomethylmercury (MMHg) to many of Canada's Arctic Aboriginal people. However, little is understood about the sources of MMHg to lichens in the High Arctic. We quantified MMHg, total mercury (THg) and other chemical parameters (e.g., marine and crustal elements, δ(13)C, δ(15)N, organic carbon, calcium carbonate) in lichen and soil samples collected along transects extending from the coast on Bathurst and Devon islands, Nunavut, to determine factors driving lichen MMHg and THg concentrations in the High Arctic. Lichen MMHg and THg concentrations ranged from 1.41 to 17.1 ng g(-1) and from 36.0 to 361 ng g(-1), respectively. Both were highly enriched over concentrations in underlying soils, indicating a predominately atmospheric source of Hg in lichens. However, MMHg and THg enrichment at coastal sites on Bathurst Island was far greater than on Devon Island. We suggest that this variability can be explained by the proximity of the Bathurst Island transect to several polynyas, which promote enhanced Hg deposition to adjacent landscapes through various biogeochemical processes. This study is the first to clearly show a strong marine influence on MMHg inputs to coastal terrestrial food webs with implications for MMHg accumulation in caribou and the health of the people who depend on them as part of a traditional diet.

Atmospheric mercury in the Canadian Arctic. Part I: a review of recent field measurements

Long-range atmospheric transport and deposition are important sources of mercury (Hg) to Arctic aquatic and terrestrial ecosystems. We review here recent progress made in the study of the transport, transformation, deposition and reemission of atmospheric Hg in the Canadian Arctic, focusing on field measurements (see Dastoor et al., this issue for a review of modeling studies on the same topics). Redox processes control the speciation of atmospheric Hg, and thus impart an important influence on Hg deposition, particularly during atmospheric mercury depletion events (AMDEs). Bromine radicals were identified as the primary oxidant of atmospheric Hg during AMDEs. Since the start of monitoring at Alert (NU) in 1995, the timing of peak AMDE occurrence has shifted to earlier times in the spring (from May to April) in recent years, and while AMDE frequency and GEM concentrations are correlated with local meteorological conditions, the reasons for this timing-shift are not understood. Mercury is subject to various post-depositional processes in snowpacks and a large portion of deposited oxidized Hg can be reemitted following photoreduction; how much Hg is deposited and reemitted depends on geographical location, meteorological, vegetative and sea-ice conditions, as well as snow chemistry. Halide anions in the snow can stabilize Hg, therefore it is expected that a smaller fraction of deposited Hg will be reemitted from coastal snowpacks. Atmospheric gaseous Hg concentrations have decreased in some parts of the Arctic (e.g., Alert) from 2000 to 2009 but at a rate that was less than that at lower latitudes. Despite numerous recent advances, a number of knowledge gaps remain, including uncertainties in the identification of oxidized Hg species in the air (and how this relates to dry vs. wet deposition), physical-chemical processes in air, snow and water-especially over sea ice-and the relationship between these processes and climate change.

Accumulation dynamics and cellular locations of Pb, Zn and Cd in resident and transplanted Flavocetraria nivalis lichens near a former Pb-Zn mine

Accumulation dynamics and cellular locations of lead (Pb), zinc (Zn) and cadmium (Cd) were studied in Flavocetraria nivalis lichens near the former Black Angel Pb-Zn Mine in West Greenland. Natural resident thalli were collected from four dust-contaminated sites near the mine. In addition, thalli were taken from an uncontaminated reference site and transplanted to the contaminated sites followed by a collection 1 year after. Total thalli metal contents were determined, and thalli were subjected to a sequential extraction procedure. After 1 year of transplantation, total Pb thalli contents were significantly elevated compared with initial concentrations at all sites (for Zn and Cd contents only at the two sites closest to the mine). However, transplanted thalli contained significantly less Pb (26 ± 12%), Zn (64 ± 13%) and Cd (34 ± 7 %) compared with resident thalli from these sites. Results from the sequential extraction procedure showed marked differences among Pb, Zn and Cd in the extracellular, intracellular and residual fraction. The lower total metal concentrations in transplanted compared with resident thalli at the contaminated sites were mostly due to a larger metal content bound in the residual fraction in resident thalli. In contrast, the metal content bound in the extracellular fraction were not significantly different in transplanted and resident thalli. The results indicate that extracellular-bound Pb, Zn and Cd in F. nivalis can be used as a proxy for recent (annual) atmospheric metal deposition whereas the large residual metal fraction in resident lichens indicate an accumulation of metal-containing particles in the thalli over time that includes several years of uptake.

Atmospheric deposition studies of heavy metals in Arctic by comparative analysis of lichens and cryoconite

Lichens and cryoconite (rounded or granular, brownish-black debris occurring in holes on the glacier surface) from Ny-Ålesund were used for understanding the elemental deposition pattern in the area. Lichen samples collected from low-lying coastal region and cryoconite samples from high altitudinal glacier area were processed and analysed for elements such as aluminium (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V) and zinc (Zn) through inductively coupled plasma mass spectrometry. Results showed that heavy metals, Al and Fe, are present in high concentration in the cryoconite samples. Al was also present in high amounts in seven of the eight lichen samples studied. The general scheme of elements in the decreasing order of their concentrations for most of the cryoconite samples was Al > Fe > Mn > Zn > V > Pb > Cr > Ni > Cu > Co > As > Cs > Cd while that for the lichen samples was Al > Fe > Zn > Mn > Pb > Cu > Cs > Cr > Ni > V > Co > As > Cd. Similarity in trends in the two sample types confirms that the environment indeed contains these elements in that order of concentration which overtime got accumulated in the samples. Overall comparison showed most elements to be present in high concentrations in the cryoconite samples as compared to the lichen samples. Within the lichens, elemental accumulation data suggests that the low-lying site (L-2) from where Cladonia mediterranea sample was collected was the most polluted accumulating a number of elements at high concentrations. The probable reasons for such deposition patterns in the region could be natural (crustal contribution and sea salt spray) and anthropogenic (local and long-distance transmission of dust particles). In the future, this data can form a baseline for monitoring quantum of atmospheric heavy metal deposition in lichens and cryoconite of Svalbard, Arctic.

Trends of lead and zinc in resident and transplanted Flavocetraria nivalis lichens near a former lead-zinc mine in West Greenland

This study investigated spatial and temporal trends of lead (Pb) and zinc (Zn) in resident and transplanted Flavocetraria nivalis lichens near the former Black Angel Mine in Maarmorilik, West Greenland. The objectives of the study were to evaluate resident and transplanted lichens for monitoring dust contamination and investigate trends in mine-related dust contamination near the mine. The mine operated between 1973 and 1990 and lichens were regularly sampled between 1986 and 2009. When the mine operated, elevated concentrations of Pb, Zn and other elements were observed in resident lichens up to 35 km from Maarmorilik. In the period after mine closure, Pb and Zn concentrations in resident lichens decreased with 1-11% and 0-6% per year, respectively. From 1996 to 2009, lichens were transplanted into the study area from an uncontaminated site and collected the following year. After 1 year, transplanted lichens showed elevated concentrations of Pb and Zn but contained consistently less Pb and Zn compared to resident lichens (24±23% and 63±37%, respectively). During the most recent sampling in 2009, transplanted lichens still showed significantly elevated Pb concentrations (up to a factor 270) within a distance of 20 km from Maarmorilik. Zinc concentrations were only significantly elevated at sites within 5 km from the mine. Time-series regression analyses showed no significant decreases in Pb and Zn in transplanted lichens at any of the sites during the period 1996-2009. In conclusion, our study showed that resident F. nivalis lichens could not be used to evaluate the recent annual dust contamination in Maarmorilik. Lichen transplants, however, were considered adequate for assessing spatial and temporal trends in Pb and Zn contamination from recently deposited dust. The continuous dispersal of contaminated dust in Maarmorilik almost 20 years after mine closure reveals a slow recovery from mining contamination in this arctic area.

Iridium, platinum and rhodium baseline concentration in lichens from Tierra del Fuego (South Patagonia, Argentina)

Lichen samples of Usnea barbata were used as possible biomonitors of the atmospheric background level of iridium (Ir), platinum (Pt) and rhodium (Rh) in the remote region of Tierra del Fuego (South Patagonia, Argentina). Lichens were collected in 2006 at 53 sites covering 7 different areas of the region (24 transplanted lichens of the northern region and 29 native lichen samples of the central-southern region). A microwave acidic digestion procedure was used to mineralize the samples and a sector field inductively coupled plasma mass spectrometry method was developed to quantify the elements. The study of the influence of interferences on analyte signals and a quality control procedure were carried out. The analytical protocol was further applied to evaluate Ir, Pt and Rh bioaccumulation in lichens. The detection limits obtained were 0.010 ng g⁻¹, 0.013 ng g⁻¹ and 0.030 ng g⁻¹ for Ir, Pt and Rh, respectively. Recoveries at different fortification levels were between 96.3% and 106% and precision was 3.3% on average. The metals concentration (as dry weight) spanned the following ranges: Ir, <0.010-1.011 ng g⁻¹; Pt, 0.016-2.734 ng g⁻¹; and Rh, 0.063-1.298 ng g⁻¹. Data on 7 areas were similar suggesting that no specific source, for example traffic or anthropogenic activity, influenced directly the metal concentrations in Tierra del Fuego. Values detected are more likely influenced by the long-range atmospheric transport of these pollutants and, in comparison with densely populated areas in the world, they can represent the baseline for low impacted areas.

Mercury in mosses Hylocomium splendens (Hedw.) B.S.G. and Pleurozium schreberi (Brid.) Mitt. from Poland and Alaska: understanding the origin of pollution sources

This report shows baseline concentrations of mercury in the moss species Hylocomium splendens and Pleurozium schreberi from the Kielce area and the remaining Holy Cross Mountains (HCM) region (south-central Poland), and Wrangell-Saint Elias National Park and Preserve (Alaska) and Denali National Park and Preserve (Alaska). Like mosses from many European countries, Polish mosses were distinctly elevated in Hg, bearing a signature of cross-border atmospheric transport combined with local point sources. In contrast, Alaskan mosses showed lower Hg levels, reflecting mostly the underlying geology. Compared to HCM, Alaskan and Kielce mosses exhibited more uneven spatial distribution patterns of Hg. This variation is linked to topography and location of local point sources (Kielce) and underlying geology (Alaska). Both H. splendens and P. schreberi showed similar bioaccumulative capabilities of Hg in all four study areas.

An isotopic investigation of mercury accumulation in terrestrial food webs adjacent to an Arctic seabird colony

At Cape Vera (Devon Island, Nunavut, Canada), a seabird colony of northern fulmars (Fulmarus glacialis) congregates and releases nutrients through the deposition of guano to the coastal terrestrial environment, thus creating nutrient-fertilized habitats important to insects, birds, and mammals. Here we determined whether mercury was similarly enriched in various terrestrial food web components in this High Arctic coastal ecosystem due to seabird inputs. Stable isotopes (delta(15)N, delta(13)C) were used to identify trophic linkages and possible routes of contaminant transfer in the food web. Values of delta(15)N were significantly higher in lichens and certain plants collected closer to the bird colony, demonstrating a gradient of seabird influence, and were higher at Cape Vera than our reference site at Cape Herschel, on eastern Ellesmere Island, an area relatively unaffected by seabirds. In contrast, delta(13)C showed little variation among terrestrial species, suggesting minimal influence by seabirds. Concentrations of total mercury (THg) in primary producers and phyto/zooplankton were not significantly correlated with distance from the seabird colony or delta(15)N values, and were similar to other taxa from the High Arctic. Our results provide novel data on THg in several Arctic taxa where concentrations have not been reported previously. Moreover, the analyses indicate that delta(15)N is significantly enriched in the adjacent environment by guano fertilization, but our study was unable to show an enrichment of THg and delta(13)C in the terrestrial food web near the seabird colony.

Can pine needles indicate trends in the air pollution levels at remote sites?

Data from ten years of integrated monitoring were used here to evaluate whether pine needles are a feasible tool for an assessment of long-term trends of the atmospheric contamination. Pine needles collected once a year were compared to high volume air samples collected for 24 h, every 7 days, and passive air samples integrated over 28-day periods. Results showed the same concentration patterns of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) captured in needles and high volume samples. Passive air samplers were less efficient in sampling the particle-bound compounds. Theoretical air volume equivalent to each needle sample (V(EQ)) was calculated as a ratio of the needle concentration over the mean air concentration. Results indicated different equivalent volumes for PAHs and organochlorines, possibly due to the faster degradation rates of PAHs in needles. The most important finding is that in the long term a needle monitoring gives very similar information on temporal trends of the atmospheric pollution as does a high volume air monitoring.

Critical review of mercury fates and contamination in the Arctic tundra ecosystem

Mercury (Hg) contamination in tundra region has raised substantial concerns, especially since the first report of atmospheric mercury depletion events (AMDEs) in the Polar Regions. During the past decade, steady progress has been made in the research of Hg cycling in the Polar Regions. This has generated a unique opportunity to survey the whole Arctic in respect to Hg issue and to find out new discoveries. However, there are still considerable knowledge gaps and debates on the fate of Hg in the Arctic and Antarctica, especially regarding the importance and significance of AMDEs vs. net Hg loadings and other processes that burden Hg in the Arctic. Some studies argued that climate warming since the last century has exerted profound effects on the limnology of High Arctic lakes, including substantial increases in autochthonous primary productivity which increased in sedimentary Hg, whereas some others pointed out the importance of the formation and postdeposition crystallographic history of the snow and ice crystals in determining the fate and concentration of mercury in the cryosphere in addition to AMDEs. Is mercury re-emitted back to the atmosphere after AMDEs? Is Hg methylation effective in the Arctic tundra? Where the sources of MeHg are? What is its fate? Is this stimulated by human made? This paper presents a critical review about the fate of Hg in the Arctic tundra, such as pathways and process of Hg delivery into the Arctic ecosystem; Hg concentrations in freshwater and marine ecosystems; Hg concentrations in terrestrial biota; trophic transfer of Hg and bioaccumulation of Hg through food chain. This critical review of mercury fates and contamination in the Arctic tundra ecosystem is assessing the impacts and potential risks of Hg contamination on the health of Arctic people and the global northern environment by highlighting and "perspectiving" the various mercury processes and concentrations found in the Arctic tundra.

Testing differences in methods of preparing moss samples

Various methods are currently used to prepare moss samples prior to their analysis in biomonitoring surveys. To date there has been no investigation of whether different results are obtained by using different preparation techniques. We therefore selected three preparation procedures (freezing, drying and acclimatization), currently applied in the European Moss Survey and other studies, to test whether significantly different concentrations of Al, As, Cd, Cr, Cu, Fe, Hg, K, Ni, Pb, Se, V and Zn are obtained. In addition, we considered the effect that the degree and type of contamination of the sampling sites and the different times of the year may have on the results. We found significant differences in the concentrations of all elements in the moss samples subjected to the different procedures and recommend standardization of the methods of sample preparation for valid comparison of the results. We further recommend that the samples are picked over directly in the field, to remove adhering material, and then cleaned prior to analysis.

Lichens as bioindicators of atmospheric heavy metal pollution in Singapore

Lichens have been used as bioindicators in various atmospheric pollution assessments in several countries. This study presents the first data on levels of heavy metals (As, Cd, Cu, Ni, Pb, and Zn) in lichens at different locations in Singapore, Southeast Asia. Singapore is a fully industrialised island nation, with a prevailing tropical climate and a population of 4 million people within a confined land area of less than 700 km2. The ubiquitous lichen species, Dirinaria picta was collected from six sample sites across Singapore and analysed for heavy metals using inductively coupled plasma mass spectrometry (ICPMS). No significant relationship existed between metal levels in lichen and soil, indicating that accumulated metals in lichen are primarily derived from the atmosphere. Peak concentrations of zinc (83.55 microg g(-1)), copper (45.13 microg g(-1)) and lead (16.59 microg g(-1)) in lichens were found at Sembawang, Jurong and the National University of Singapore campus which are locations associated with heavy petroleum and shipping industries, and road traffic respectively. The mean heavy metal levels of lichen samples in Singapore were found to be at the upper range of values reported in the literature for temperate countries.

Determination of baseline element composition of lichens using samples from high elevations

The results of a survey aimed at providing baseline element composition of lichens from unpolluted or very low polluted areas are reported. Lichen samples collected at high elevation areas in Himalayas (Nepal), Mt. Kenya (Kenya) and the Alps (Italy) were analyzed for their trace element content, mostly by INAA, allowing for a multi-element analysis. The elemental composition of lichen samples was essentially influenced by natural occurrence, mainly airborne soil dust. However, also anthropogenic input determined by long-distance atmospheric transport of pollutants was involved for some highly volatile elements such as Br, Cd and Sb. To avoid the influence of soil contamination and air pollution, and obtain baseline concentrations to be used as reference (the "natural" elemental composition of lichens), the average of the lowest concentrations is suggested.

Distribution of trace metals in moss biomonitors and assessment of contamination sources in Portugal

A biomonitoring survey using the moss species [Hypnum cupressiforme Hedw. and Scelopodium touretii (Brid.) L. Kock] was performed in the whole territory of Portugal, in order to evaluate the atmospheric deposition of the following elements: Cd. Cr, Cu, Fe, Mn, Ni, Pb and Zn. The concentrations of the same elements were also obtained in two types of soil samples, collected under the moss and in nearby plots without any plant coverage, and relationships between moss and soil concentrations was investigated using the multivariate statistical method of Co-inertia Analysis. Also, relationships between concentrations in moss and several anthropogenic, geologic, pedologic and environmental parameters were screened using the same method of Co-inertia Analysis. Higher concentrations of Cu, Pb and Zn were found in areas of higher population density, with higher gasoline consumption, while higher values of Fe and Cr occur in the driest region, with lower plant coverage, indicating strong contamination by resuspended soil particles. Results also show good agreement between moss and soil contents, even for elements with high contribution of anthropogenic sources. The spatial pattern in Portugal of element contents in mosses were also detected and discussed in relation to local contamination sources.

Biomarkers as biological indicators of xenobiotic exposure

The presence of a xenobiotic in the environment always represents a risk for living organisms. However, to talk about impregnation there is a need to detect toxicity in the organism, and the concept of intoxication is related to specific organ alterations and clinical symptoms. Moreover, the relationship between the toxic levels within the organism and the toxic response is rather complex and has a difficult forecast because it depends on several factors, namely toxicokinetic and genetic factors. One of the methods to quantify the interaction with xenobiotics and its potential impact on living organisms, including the human being, is monitoring by the use of the so-called biomarkers. They can provide measures of the exposure, toxic effect and individual susceptibility to environmental chemical compounds and may be very useful to assess and control the risk of long-term outcomes associated with exposure to xenobiotic (i.e. heavy metals, halogenated hydrocarbons, pesticides).