Accumulation of Polycyclic Aromatic Hydrocarbons in Soils and Mosses of Southern Tundra at Different Distances from the Thermal Power Plant

A number of polycyclic aromatic hydrocarbon (PAH) structures have been identified in organic horizons of surface-gley tundra soils (Stagnic Cambisols) and the moss Pleurozium schreberi. The total content of polyarenes in soils and P. schreberi exceeds the background values in 3.5–5 times. A tendency of increasing content of polyarenes with the distance from the source to 1 km has been revealed. High coefficients of variation have been found between the contents of PAHs in snow cover, organic soil horizons, and mosses. Light hydrocarbons dominate in the composition of PAHs from the snow and ground covers and mosses. Naphthalene dominates on the surface of mosses in all of the studied plots, which is largely related to its intensive uptake by mosses under pollution conditions. It has been found that when the input of polyarenes onto the surface of tundra phytocenoses increases, the bioaccumulation of PAHs by P. schreberi is intensified, and PAHs begin to penetrate into moss. The increase in the concentration of high-molecularweight polyarenes in the environment plays the key role in the activation of PAH bioaccumulation by moss. It has been shown that P. schreberi can be used as an indicator species for monitoring the contamination of tundra phytocenoses by polyarenes. Both living and dead parts of P. schreberi are suitable for the environmental monitoring of PAH contamination.     

Estimation method of residual alkylating agents in water treated with chloring-containing oxidant

Concentrations of trace metals in mosses Hylocomium splendens (Hs) and Pleurozium schreberi (Ps) are compared along with wet deposition at 8 sites in Sweden. Cd, Mn, Zn and Cr concentrations were similar in both mosses, while Cu, Fe, Pb, Ni and V levels were 14 to 24% higher in Hs than in Ps. The comparison to wet deposition estimates indicates that concentrations in mosses are also influenced by other factors than the adsorption of precipitation. No correlation was observed between the wet deposition of Mn, Cr and Ni and moss concentrations.     

Are cadmium, lead and mercury concentrations in mosses across Europe primarily determined by atmospheric deposition of these metals?

Purpose

This study aimed at investigating correlations between heavy metal concentrations in mosses and modelled deposition values as well as other site-specific and regional characteristics to determine which factors primarily affect cadmium, lead and mercury concentrations in mosses. The resulting relationships could potentially be used to enhance the spatial resolution of heavy metal deposition maps across Europe.

Materials and methods

Modelled heavy metal deposition data and data on the concentration of heavy metals in naturally growing mosses were integrated into a geographic information system and analysed by means of bivariate rank correlation analysis and multivariate decision trees. Modelled deposition data were validated annually with deposition measurements at up to 63 EMEP measurement stations within the European Monitoring and Evaluation Programme (EMEP), and mosses were collected at up to 7,000 sites at 5-year intervals between 1990 and 2005.

Results and discussion

Moderate to high correlations were found between cadmium and lead concentrations in mosses and modelled atmospheric deposition of these metals: Spearman rank correlation coefficients were between 0.62 and 0.67, and 0.67 and 0.73 for cadmium and lead, respectively (p?<?0.001). Multivariate decision tree analyses showed that cadmium and lead concentrations in mosses were primarily determined by the atmospheric deposition of these metals, followed by emissions of the metals. Low to very low correlations were observed between mercury concentrations in mosses and modelled atmospheric deposition of mercury. According to the multivariate analyses, spatial variations of the mercury concentration in mosses was primarily associated with the sampled moss species and not with the modelled deposition, but regional differences in the atmospheric chemistry of mercury and corresponding interactions with the moss may also be involved.

Conclusions

At least for cadmium and lead, concentrations in mosses are a valuable tool in determining and mapping the spatial variation in atmospheric deposition across Europe at a high spatial resolution. For mercury, more studies are needed to elucidate interactions of different chemical species with the moss.     

Aquatic mosses for the detection and follow-up of accidental discharges in surface waters

Aquatic mosses have been used to study four accidental discharges of the heavy metals Cd, Zn and Hg or the chlorinated hydrocarbons pentachlorophenol (PCP) and lindane in highly contrasting river types. Hg, PCP and lindane moss concentrations reached 880, 4500 and 350 ng g^?1, respectively. In the case of Cd and Zn, water samples and transferred bioindicators were taken simultaneously throughout an accidental discharge. The very high dissolved metal concentrations reached during this accident (9 mg L^?1 Zn, 90 μg L^?1 Cd) induced accumulation by the mosses of up to 28 mg g^?1 for Zn and 225 μg g^?1 for Cd. The increase in concentrations in the mosses was as rapid and substantial as in the water, the time lag due to accumulation kinetics being almost zero. On the other hand, the memory effect enabled mosses to retain marked evidence of Cd, Zn, Hg, PCP and lindane up to 13 days after the accident when difference from background levels can hardly be detected in the water. The four case studies, which killed fish, but not the mosses, show that the previously established scales of quality based on the analysis of aquatic mosses are well suited to estimating the potential damage to the aquatic ecosystem as a whole.     

The Geochemistry of Ombrotrophic Sphagnum Species Growing in Different Microhabitats Of Eight German and Belgian Peat Bogs and the Regional Atmospheric Deposition

Comparing today’s atmospheric deposition records with the elemental concentration and the net-uptake rates of ombrotrophic Sphagnum mosses from eight German and Belgian peat bogs revealed that most of all the quality and number of regularly obtained deposition monitoring data is not satisfactory. Moreover, it seems likely that the deposition rate, determined by Sphagnum mosses, does not reliably reflect the record of the total open field deposition indicated by the deposition monitoring data. The moss data, too, show a distinct spatial variability possibly because the geochemistry of peat mosses differs according to the annual growth in height, the total surface area and the surface roughness of the receptor ‘peat moss’ (special interception deposition). Increased Ti concentration values, for example, combined with a high annual growth rate in height at the hollow moss S. cuspidatum resulted in generally high Ti net-uptake rates and a high Ti inventory (total Ti in sample). We, therefore, suggest that productive Sphagnum species might be able to fix more Ti particles on their larger surface area than less productive species do. Moreover, the results demonstrate that for reliably calculating Sphagnum elemental net-uptake rates, as well as for all quantification of Sphagnum or peat geochemistry on a time and area basis, an accurate knowledge of the period the collected samples were exposed to atmospheric deposition is required. In particular, to do reliable reconstructions of past atmospheric deposition rates using peat deposits, further studies are needed to precisely specify the spatial variability in the geochemistry of living Sphagnum mosses.     

Mechanisms for Translocation of Heavy Metals from Soil to Epigeal Mosses

The mechanisms for translocation of heavy metals from soil to epigeal mosses were investigated. The first mechanism was demonstrated for ¹³⁷Cs and involved the uplifting of the pollutant-containing dust from the soil, followed by the local secondary deposition on surfaces of epigeal mosses and epiphytic lichens. The second mechanism involved the diffusion of metal cations from the soil through water wetting the moss into the gametophyte. The mechanism was demonstrated by measuring the electric conductance of wetted gametophytes with single ends immersed in solutions of Cu and Na salts. In addition, the concentrations of Cu and Cd were compared in moss samples exposed to the natural soil and to the soil contaminated with the metals. The exposition to the contaminated soil resulted in the statistically significant increase of metal concentrations in the gametophytes.     

The nitrogen regime and biological fixation of nitrogen in moss communities (the Khibiny Mountains)

In the vegetation belts of the Khibiny Mountains, the dynamics of the contents of mineral and easily hydrolyzable (according to Cornfield) nitrogen compounds in the litter and the nitrogen-fixing capacity of epiphytic cyanobacteria on dominant mosses were studied. The nitrogen regime of most moss species was shown to be self-supporting probably due to the intense assimilation of molecular nitrogen by epiphytic cyanobacteria (during the growing period, up to 28% of the total nitrogen content in plants) and the low organic matter production by mosses.     

Accumulation Capacities of Particulate Matter in an Acrocarpous and a Pleurocarpous Moss Exposed at Three Differently Polluted Sites (Industrial, Urban and Rural)

The aim of this study was to compare the capacity of two morphologically different moss species to accumulate elements when exposed to three different types of air pollution (rural, urban and industrial). Transplants of Pseudoscleropodium purum and Ceratodon purpureus were exposed for 6 months, and the concentrations of 18 elements (Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, As, Mo, Cd, Sn, Sb, Ba, La, Pb and Bi) in the mosses samples were analysed by inductively coupled plasma–mass spectrometry. On the whole, the metals were accumulated by mosses, and this accumulation was correlated with concentrations in the atmospheric particles. Whereas P. purum is to be preferred for Al, Cu, Zn and Fe monitoring, C. purpureus was most efficient at accumulating Mo, Ti, V, As, Sn, La and Pb. In both species, a phenomenon of saturation was observed during the exposure at the most contaminated site (industrial).     

Towards sustainable commercial moss harvest in the Pacific Northwest of North America

The Pacific Northwest is the main source of commercially harvested forest moss in North America, but management guidelines have only included this nontimber forest product for ca. 15 years and research on sustainable harvest practices is barely a decade old. This review summarizes the results of recent research, identifies future research needs, and proposes guidelines for the sustainable management of tree moss (a mixture of mosses and liverworts). The epiphytic species most affected by harvest are Isothecium myosuroides, Neckera douglasii, and Porella navicularis, but dozens of taxa are thought to be impacted. Harvest impacts include reductions in biomass and cover and changes in relative species composition, but it is too early to tell if the species composition will return to pre-harvest conditions. Biomass recovery is slow and estimated rotation periods are 15-25 years. Inventory estimates are still lacking, but harvestable quantities of epiphytic moss are most abundant in low elevation and riparian areas and absent in stands that are very dark and/or lack hardwood tree and shrub species (e.g., <70-year-old Douglas-fir (Pseudotsuga menziesii) plantations). Future research should focus on locating unimpacted reference sites and evaluating the ecosystem functions provided by harvestable moss mats, including the provision of habitat and nutrient and water cycling. Management recommendations include prohibiting commercial moss harvest in forests managed toward old-growth condition, obtaining region-specific estimates of resource inventory and recovery rates, and rotating areas open for moss harvest to allow sufficient recovery between harvest entries.     

Mercury in vegetation and lake sediments from the U. S. arctic

Global atmospheric concentrations of mercury (Hg) appear to be increasing and with it the potential for ecosystem exposure and ecological effects. From 1990 to 1993 we examined U. S. arctic ecosystems over a broad spatial scale to develop baseline information on current concentrations of trace elements, heavy metals (including Hg), persistent organic compounds, and radionuclides in various components of the terrestrial and freshwater biosphere. Matrices reported here include, vegetation (lichens and mosses) and lake sediments. Total Hg in two lichen and two moss species from Alaska were generally low (0.02–0.112 μg/g dw), compared to reported values from other arctic locations and showed a statistically significant negative relationship between total Hg content and distance from the marine coastline.²¹⁰Pb dated sediment cores indicated that average preindustrial total Hg accumulation rates were over four times greater in arctic Schrader lake than in subarctic Wonder Lake. Both lakes indicated a small increase (5–8%) in total Hg flux to the sediments during the last 145 years, much smaller than similar increases in total mercury for lakes in the north central U. S. The likely source of recent increases in Hg in these Alaskan ecosystems is long range atmospheric transport. While we can detect increases in mercury in lake sediments likely due to anthropogenic activities, values are low and there appears to be no immediate threat to terrestrial environments and inland freshwaters of arctic Alaska from long range atmospheric transport and deposition of Hg.     

Acidic precipitation in Western North America: Trends,sources, and altitude effects in New Mexico 1979–1985

Volume-weighted pH values in central New Mexico have averaged 3.8 to 5.1 during the period 1979–1985. Samples collected at a high altitude site (3200m) have lower pH values than found for low altitude samples (1400m). Both dry deposition and event-averaged pH values have been higher than the volume-weighted averages due to neutralization by terrestrial material. During the period 1980–1984, changes in pH values and wet sulfate loading have correlated to S0₂ emissions from regional non-ferrous smelters. Sulfur isotope analyses of sulfate extracted from regional rain samples yielded a δ³⁴S_CD(%) of + 3.91 ± 1.1, indicating very little regional differentiation which, in turn, suggests that the regional atmospheric sulfate scavenged by precipitation is well-mixed and relatively homogeneous.     

Cesium-137 Monitoring Using Mosses from Macedonia,N. Greece

137Cs activities in mosses collected from four sites in Macedonia, N. Greece were measured for regular periods of time during the last decade following the reactor accident in Chernobyl. Samples taken in 1985 allow to determine the 137Cs contamination before the accident. A clear increase of the cesium interception was observed for about two years after the accident. Later a gradual decrease was detected which depended on various factors such as moss species, location, growth rate and substrate. Higher 137Cs amounts were observed in epilithic (Grimmia) in comparison to epiphytic or epigeic ones ( Encalypta, Tortula). From the studied biotopes Mt. Vermion presented the highest 137Cs activities. The high 137Cs values found 10 yr after Chernobyl suggest that mosses are effective and inexpensive biological detectors of the distribution and burden of fallout radionuclides.     

Composition,distribution and sources of polycyclic aromatic hydrocarbons in sediments of the western harbour of alexandria,egypt

Aim and Background  Little data are available on the levels of polycyclic aromatic hydrocarbons (PAHs) in the sediments of the Mediterranean Sea Coast of Egypt in general and the Alexandria coastal zone in particular. It was therefore deemed necessary to set up a monitoring programme to determine the current concentrations of PAHs in bottom sediments, and to identify any area where high concentrations of these potential hazardous contaminants were present in the Western Harbour of Alexandria. Methods  The composition, distribution and the source of PAHs in surficial sediments of the harbour were investigated. To document the spatial PAH input, surficial sediment samples from 23 locations throughout the harbour were analysed. as]Results and Discussion The total PAH load determined in the surficial sediment samples ranged from 8 to 131150 ng g¹ dry wt, generally with most of the samples having total concentrations of PAHs greater than 5000 ng g¹ dry weight. The highest concentration of total PAHs was recorded in sediments of the inner harbour. Ratio values of specific compounds such as phenanthrene to anthracene, fluoranthrene to pyrene, methyl-phen-anthrene to phenanthrene, methyl-dibenzothiophenes to dibenzothiophenes, alkylated to non-alkylated and high molecular weight to low molecular weight PAH, were calculated to evaluate the possible source of PAH contamination in the harbour sediments. Conclusions  Two main sources of PAH in the study area have been found: pyrolytic and petrogenic. Interferences of rather petrogenic and pyrolytic PAH contaminations were noticed for most samples. The dominant sources of PAH appear to be the combustion processes through run-off, industrial and sewage discharges, and atmospheric input. The concentrations of PAHs were generally above levels expected to cause adverse biological effects. Recommendations and outlook  Information from this study and any other relevant studies should be useful in designing future strategies for environmental protection and management of the harbour.     

Mosses as bioindicators of heavy metal pollution in polish national parks

The concentrations of heavy metals (Cd, Co, Cr, Ni, Cu, Ph, Zn, Mn, Fe) and other elements (Mg, Na, K, Ca) were determined in the samples of Pleurozium schreberi and Hylocomium splendens from 12 Polish national parks. The significant differences in the concentrations of all heavy metals between particular parks were found. The lowest concentrations of these metals were recorded in the mosses from the national parks in northern Poland, the highest in southern Poland. Significant differences in the heavy metals contents of the mosses between central and peripheral park areas, between green and brown parts of mosses, as well as between moss species were also found.     

Assessment of Atmospheric Heavy Metals by Moss Monitoring with Isothecium Stoloniferum Brid. in the Fraser Valley, B.C., Canada

The atmospheric heavy metal pollution of the Fraser Valley, B.C., Canada was assessed in 1993 by analyzing 62 samples of the common woodland moss Isothecium stoloniferum for lead, cadmium, nickel, zinc, chromium, and manganese. The latter two metals did not show a distinct regional distribution, but lead, cadmium, nickel, and zinc showed distinct pattern along a west-east gradient. High values were found in the metropolitan Vancouver area, located in the west of the study region. Significantly lower values were recorded for mosses from the eastern more rural areas of the Fraser Valley. Metal pollutants are likely to be contained close to their emission sources by alternating south-east, north-west winds. Highest values overall were found in the North Shore Mountains, adjacent to Vancouver. This was related to higher precipitation and short range pollutant transport from the industrialized, heavily populated areas in the floodplain of the Fraser River.     

THE TRAPPING OF FLY-ASH PARTICLES IN THE SURFACE LAYERS OF SPHAGNUM-DOMINATED PEAT

The movement of fly-ash particles in a sequence ofSphagnum moss was studied in laboratory experiments and field investigations. The data obtained in the laboratory show that only 0.8% of particles, placed on the surface of a 6–10 cm thickSphagnum layer, were washed out with water (700–750 mm) during the 241 days of the experiment. The majority of added particles were fixed in the upper part (90% in 1–3 cm) of the moss layer. A SEM study indicates that sorption is slightly species-dependent due to the micromorphological parameters of theSphagnum species. The storage of particles bySphagnum mosses allows the use of natural sequences to study the history of atmospheric pollution. The distribution of particles in the upper part of moss layers in Viru Bog (50 km east of Tallinn, North Estonia) shows good agreement with the known air pollution history in Tallinn.     

A Study of the Oxygen Isotopic Composition of Precipitation Sulphate in Eastern Newfoundland

The properties of stable oxygen isotopes make them useful for studying processes involved in the atmospheric oxidation of sulphur compounds. Experimental work in the 1980s reported that the formation of primary combustion sulphates by high temperature oxidation of SO2(g) to SO4 leads to δ18OSO4 values between +40 and +45‰. This study reports sulphate oxygen isotopic compositions from precipitation events collected at two sites in eastern Newfoundland. Values as high as +41.7‰ were measured in natural precipitation samples collected near a small oil-fired power plant located on the campus of Memorial University of Newfoundland in St. John's. These values are higher by 16‰ than any previously reported for precipitation in the literature and in conjunction with other chemical data implicate the power plant as the pollution source. Values from the second site (Seal Cove) were similar to previously reported ranges for precipitation, despite its proximity to a much larger oil-fired, thermal generating station, suggesting that different oxidation mechanisms were dominant there. Oxygen isotopic compositions of precipitation sulphates can be an important complementary tool to other isotopic, trace metal and meteorological analysis in the tracing of sources of atmospheric sulphur compounds.     

Atmospheric deposition of trace elements in Norway: Temporal and spatial trends studied by moss analysis

The atmospheric deposition of sixteen trace elements, as inferred by their concentration in moss samples collected in 1985 from 500 sites in Norway, is compared with data from a similar survey in 1977. The deposition patterns of V, Zn, As, Se, Cd, Sb, and Pb are substantially influenced by long-range transport from other parts of Europe, but a general decline is evident from 1977 to 1985, most strongly for Pb. For Cr, Fe, Co, Ni, and Cu the deposition patterns are largely determined by contributions from point sources within Norway and on the Kola peninsula close to the Russian/ Norwegian border. The moss data for Br, I, and partly Se reflect airborne supply from the marine environment, whereas Al and Sc serve as indicators of contributions from soil dust. Contributions to the trace element concentrations in moss from sources other than atmospheric deposition are identified and discussed.     

Long-Range Atmospheric Transport and Local Pollution Sources on PAH Concentrations in a South European Urban Area. Fulfilling of the European Directive

A 12 months study on urban atmospheric concentrations of polycyclic aromatic hydrocarbons (PAH) contained in the particulate matter with an aerodynamic diameter less than or equal to 10 microns (PM10) was carried out in Zaragoza (Spain) from July 12th, 2001 to July 26th, 2002 by using a high-volume air sampler able to collect the PAH supported on a Teflon-coated fibre glass filter. Samples were analysed by using Gas Chromatography Mass Spectrometry (GC-MS/MS). PAH of high molecular weight, indeno[1,2,3-cd]pyrene (IcdP), benzo[g,h,i]perylene (BghiP) and coronene (Co) were the most abundant compounds. The concentrations of benz[a]pyrene equivalent carcinogenic power (BaP-eq) showed a mean value of 0.7 ng/m³ with 22.5% of the samples exceeding the 1.0 ng/m³ guide value established by the European Directive. These episodes were mainly produced during cold season. Regarding meteorological variables, a positive effect of the prevalent wind “cierzo” (NW direction) over the Zaragoza city was confirmed from the environmental point of view. The NE, E and S directions, corresponding to highway and industrial areas were the directions showing the high PAH atmospheric concentrations. Despite the proximity of a high-level traffic highway, stationary sources related to industry were the dominant source of PAH in the sampled area. Vehicular emissions and natural gas home heating also contributed to PAH concentrations. The predominance of local pollution sources versus long-range transport on PAH concentrations was shown. However, the contribution of long-range transport of anthropogenic origin from other European areas was reflected for specific dates on PAH concentrations and PM10 levels.     

Correlation between Environmental Conditions and the Distribution of Mosses Exposed to Urban Air Pollutants

Moss surveys have several advantages over conventional depositionmonitoring based on precipitation, and allow the study of regional differences and temporal trends of airborne pollution. The purposes of this study were to: (i) describe the moss species growing in one of the largest industrial cities in Asia, (ii) document edaphic and atmospheric conditions at each site, (iii) collect materials and data for a program of regular moss monitoring, previously lacking in the Far East, (iv) uncover correlations among atmospheric and edaphic factors expected to influence moss growth. As a result, a total of fifteen moss species were recorded in twenty-five sites in Seoul, Korea, and most sites had four or five species. Each species' density was affected by soil parameters, but density of Pogonatum nessii and Taxiphyllum taxirameum was also affected by CO. In contrast, SO₂ was the only environmental variablethat significantly affected the composition of moss communities. On the whole, species diversity rather than abundance of specific moss species might be a good indicator of atmospheric contamination in Seoul. This investigation will help fill the gap in knowledge of the interactions between environmental pollution and moss vegetation under field conditions.