Endosulfan, pentachlorobenzene and short-chain chlorinated paraffins in background soils from Western Europe

Soils are major reservoirs for many persistent organic pollutants (POPs). In this study, "newly" regulated POPs i.e. Σendosulfans (α-endosulfan, β-endosulfan, endosulfan sulfate), pentachlorobenzene (PeCB), and short-chain chlorinated paraffins (SCCPs) were determined in background samples from woodland (WL) and grassland (GL) surface soil, collected along an existing latitudinal UK-Norway transect. Statistical analysis, complemented with plots showing the predicted equilibrium distribution and mobility potential, was then explored to discuss factors controlling their spatial distribution. SCCPs were detected with the highest average concentrations (35 ± 100 ng/g soil organic matter (SOM)), followed by Σendosulfans (3 ± 3 ng/g SOM) and PeCB (1 ± 1 ng/g SOM). PeCB and Σendosulfans share many similarities in their distribution in these background soils as well as with several legacy POPs. A steep decline in concentrations of SCCPs with increasing latitude indicates that their occurrence is dictated by proximity to source regions, while concentrations of Σendosulfans peaked in regions experiencing elevated precipitation rates.

Essential and non-essential elements in natural vegetation in southern Norway: contribution from different sources

Concentrations of essential and non-essential elements in five widespread species of natural boreal vegetation were studied with respect to seasonal variation and contribution from different sources. The plant species included in the study were Betula pubescens, Sorbus aucuparia, Vaccinium myrtillus, Vaccinium uliginosum, Calluna vulgaris and Deschampsia flexuosa. Concentrations of elements essential to plants remained essentially constant or decreased slightly throughout the growing season. Concentrations of most non-essential elements increased or tended to increase on a dry mass basis from June to July as well as from July to September. The increasing trend for these elements was observed for all species except C. vulgaris. Principal component analysis (PCA) of the material indicated a common source for many of the non-essential elements; Sc, Ti, V, Ga, As, Y, Sb, lanthanides, Pb, Bi, and U, i.e. both elements presumably of geogenic origin and elements associated with trans-boundary air pollution. Uptake by plant roots appeared to be the main source of nutrient elements as well as some non-essential elements.

Influence of chemical composition of precipitation on migration of radioactive caesium in natural soils

The aim of the present work was to study the impact of the chemical composition of precipitation on radiocaesium mobility in natural soil. This was done through column studies. Three types of precipitation regimes were studied, representing a natural range found in Norway: Acidic precipitation (southernmost part of the country); precipitation rich in marine cations (highly oceanic coastal areas); and low concentrations of sea salts (slightly continental inland areas). After 50 weeks and a total precipitation supply of ∼10 000 L m(-2) per column, results indicate that acidic precipitation increased the mobility of (134)Cs added during the experiment. However, depth distribution of already present Chernobyl fallout (137)Cs was not significantly affected by the chemical composition of precipitation.

Leaching of polycyclic aromatic hydrocarbons from oil shale processing waste deposit: a long-term field study

The leaching behavior of selected polycyclic aromatic hydrocarbons (PAHs) from an oil shale processing waste deposit was monitored during 2005-2009. Samples were collected from the deposit using a special device for leachate sampling at field conditions without disturbance of the upper layers. Contents of 16 priority PAHs in leachate samples collected from aged and fresh parts of the deposit were determined by GC-MS. The sum of the detected PAHs in leachates varied significantly throughout the study period: 19-315 μg/l from aged spent shale, and 36-151 μg/l from fresh spent shale. Among the studied PAHs the low-molecular weight compounds phenanthrene, naphthalene, acenaphthylene, and anthracene predominated. Among the high-molecular weight PAHs benzo[a]anthracene and pyrene leached in the highest concentrations. A spent shale deposit is a source of PAHs that could infiltrate into the surrounding environment for a long period of time.

Geographical trends in 137Cs fallout from the Chernobyl accident and leaching from natural surface soil in Norway

In order to follow the turnover of (137)Cs in natural soils and estimate future trends in exposure of livestock, samples of natural surface soils were collected at 0-3 cm depth at 464 sites in 1995 and 463 sites in 2005 covering the country. In both cases the geographical pattern observed was similar to the original distribution from 1986, but the decline of (137)Cs activity in the surface soil was not the same everywhere. In 1995 the (137)Cs reduction since 1986 was found to be considerably greater in coastal areas than farther inland. The main reason for this appears to be the much greater deposition of marine cations such as Mg(2+) and Na(+) in the coastal areas, replacing Cs ions fixed on soil particle surfaces. This cation exchange appeared to be particularly strong near the southern coast where deposition of NH4(+) from transboundary air pollution is evident in addition to the marine cations. During 1995-2005 the (137)Cs decline in the surface soil was more uniform over the country than in the preceding 10-year period but still significantly higher in coastal areas than inland. Differences in precipitation chemistry may have influenced the uptake of (137)Cs in terrestrial food chains.

Analysis of selected biomonitors to evaluate the suitability for their complementary use in monitoring trace element atmospheric deposition

The biomonitoring properties of oak tree bark compared with the epiphytic moss Hypnum cupressiforme and the influence of the tree bark, as its growth substrate, on the content of heavy metals in moss were investigated. Samples of the epiphytic moss H. cupressiforme and oak tree bark (Quercus spp.) were collected in Eastern Romania at a total of 44 sampling sites. Parallel moss and bark samples were collected from the same sides of the trunk circumference. V, Cr, Ni, Cu, Zn, As, Mo, Cd, In, Tl, Sn, Pb, and Bi were determined by ICP-MS. Principal component analysis was used to identify possible sources of metals in bark and moss. Six factors explaining 87 % of the total variance in the data set were chosen. The main factors represent long-range atmospheric transport of elements (Zn, Cd, (Pb), Bi, (Mo), (Tl)), local emissions from industrial sources (As, Cr, Ni, V), road traffic (Pb, Zn) and agricultural activities (Cu, (Zn)). The element concentrations in moss and bark samples are of the same order of magnitude. For almost all the elements, higher concentrations were obtained in moss. Significant correlations between concentrations in moss and bark samples were obtained for 7 of the 13 elements: V, Ni, Cu, Zn, Cd, In, and Bi, all typical anthropogenic pollutants. The use of tree bark for monitoring purposes might be an alternative in areas where there is a scarcity of mosses.

Distributions of (137)Cs and (210)Pb in moss collected from Belarus and Slovakia

In the present work, moss samples collected in Slovakia and Belarus were assayed with respect to gamma-emitting radionuclides. The results for (137)Cs and (210)Pb are discussed. Moss was used for the first time in Belarus, as a biological indicator of radioactive environmental pollution in consequence of the Chernobyl accident in 1986. In Belarus, the maximum activity of (137)Cs was observed in the Gomel region near Mazyr (6830 Bq/kg) and the minimum activity in the Vitebsyevsk Region near Luzhki-Yazno (5 Bq/kg). "Hot spots" were also observed near the towns Borisow and Yuratsishki. The results of measurements of (137)Cs in moss samples collected in 2000, 2006 and 2009 in the same localities of Slovakia are presented and compared with the results of air monitoring of (137)Cs carried out in Slovakia from 1977 until 2010. Measurements of the (210)Pb concentration in moss samples collected over the territory of Slovakia showed, that the median value exceed 2.3 times median value of (210)Pb obtained for Belarus moss. For that reason, the inhalation dose for man from (210)Pb and (137)Cs in Slovakia is more than twice as high as in Belarus, in spite of the initially very high (137)Cs exposure in the latter country.

Spatiotemporal distribution of airborne elements monitored with the moss bags technique in the Greater Thriasion Plain, Attica, Greece

The well-known moss bags technique was applied in the heavily polluted Thriasion Plain region, Attica, Greece, in order to study the spatiotemporal distribution, in the atmosphere, of the following 32 elements: Na, Al, Cl, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, Zn, As, Se, Br, Sr, Mo, Sb, I, Ba, La, Ce, Sm, Tb, Dy, Yb, Hf, Ta, Hg, Th, and U. The moss bags were constituted of Sphagnum girgensohnii materials. The bags were exposed to ambient air in a network of 12 monitoring stations scattered throughout the monitoring area. In order to explore the temporal variation of the pollutants, four sets of moss bags were exposed for 3, 6, 9, and 12 months. Instrumental neutral activation analysis was used for the determinations of the elements. The data were analyzed using the Pearson correlations, the partial redundancy analysis, and the biplot statistical methods. Some pairs of elements were highly correlated indicating a probable common source of origin. The levels of the measured pollutants were unevenly distributed throughout the area and different pollutants exhibited different spatial patterns. In general, higher loads were observed in the stations close to and within the industrial zone. Most of the measured elements (e.g., Al, Ca, Ni, I, Zn, Cr, and As) exhibited a monotonic accumulation trend over time. Some elements exhibited different dynamics. The elements Mn, Mo, and Hg showed a decreasing trend, probably due to leaching and/or volatilization processes over time. Na and Br initially showed an increasing trend during the winter and early spring periods but decreased drastically during the late warm period. The results further suggest that the moss bags technique would be considered valuable for the majority of elements but should be used with caution in the cases of elements vulnerable to leaching and/or volatilization. It also suggests that the timing and the duration of the exposure of moss materials should be considered in the interpretation of the results.

Soil pollution with trace elements at selected sites in Romania studied by instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) was used to determine concentrations of 42 elements in samples of surface soil collected at seven sites polluted from various anthropogenic activities and a control site in a relatively clean area. Elements studied were Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Hg, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, U, V, W, Yb, Zn, and Zr. The results are compared with data for trace elements atmospheric deposition in lichen transplants from the same sites. The most severe soil contamination was observed at Copsa Mica from non-ferrous metallurgy. Appreciable soil contamination was also indicated at Baia Mare (non-ferrous mining and metallurgy), Deva (coal-fired power plant, cement and building materials industry), Galati (ferrous metallurgy), Magurele and Afumati (general urban pollution), and Oradea (chemical and light industries). In most cases excessive levels of toxic metals in soils matched correspondingly high values in lichen transplants. Compared to Romanian norms, legal upper limits were exceeded for Zn and Cd at Copsa Mica. Also, As and Sb occurred in excessive levels at given sites.

Distribution and turnover of (137)Cs in birch forest ecosystems: influence of precipitation chemistry

The aim of the present work was to study radioactive caesium in soil and plants from birch forests subject to different chemical climate. Four areas and three types of precipitation regimes were considered, representing a natural climatic range found in Norway: (A) acidic precipitation (southernmost part of the country); (B) precipitation rich in "sea salts"/marine cations (coastal areas); and (C) + (D) low concentrations of sea salts (inland areas). The results showed significant regional differences in plant uptake between the investigated areas. For instance the aggregated soil-to-plant transfer coefficients (Tag) were generally up to 7-8 times higher for the area receiving acid rain. Differences in caesium speciation partly explained the regional variability - e.g. the exchangeable fraction ranged from 1 to 40% (with the largest fraction of exchangeable caesium found in southernmost Norway). Transfer coefficients estimated on the basis of exchangeable fractions showed no significant differences between the areas of highest (A) and lowest (C) Tags. However, exchangeable fractions taken into consideration, the uptake of (137)Cs in plants in the acid rain-influenced area is still about twice that in the sea salt influenced area B. A significantly lower concentration of soluble base cations and a higher share of acid components in soils in area A is a likely explanation for this observation.

Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses

Previous analyses at the European scale have shown that cadmium and lead concentrations in mosses are primarily determined by the total deposition of these metals. Further analyses in the current study show that Spearman rank correlations between the concentration in mosses and the deposition modelled by the European Monitoring and Evaluation Programme (EMEP) are country and metal-specific. Significant positive correlations were found for about two thirds or more of the participating countries in 1990, 1995, 2000 and 2005 (except for Cd in 1990). Correlations were often not significant and sometimes negative in countries where mosses were only sampled in a relatively small number of EMEP grids. Correlations frequently improved when only data for EMEP grids with at least three moss sampling sites per grid were included. It was concluded that spatial patterns and temporal trends agree reasonably well between lead and cadmium concentrations in mosses and modelled atmospheric deposition.

Uptake of different forms of antimony by wheat and rye seedlings

PURPOSE

The objectives of the research were to study how antimony (Sb) chemical form present in the growth medium can affect Sb uptake by plants and estimate effects of Sb on wheat and rye seedlings, in particular, assess variations in concentrations of nutrients resulting from bioaccumulation of Sb.

METHODS

Seedlings were (1) germinated in media spiked with Sb(III) or Sb(V) and then transferred to clean water, and (2) germinated in Sb-free medium and then grown in water enriched with Sb. Variations of Sb concentrations in the seedlings were studied, and effects of Sb bioaccumulation on plant development and concentrations of macro- and trace elements in the plants were assessed.

RESULTS

Rye was capable of accumulating more Sb than wheat. This resulted in necrosis of the rye leaves. During germination in Sb-rich medium rye and wheat accumulated Sb differently. When the seedlings germinated in Sb-amended medium were then grown in clean water, Sb concentration in all plant parts decreased. Plant concentrations of Sb increased significantly when seedlings germinated in Sb-free medium were transferred to Sb-spiked water. However, with time saturation with Sb in the plants was observed. The bioaccumulation of Sb led to significant variations in concentrations of various elements in different plant parts.

CONCLUSIONS

Wheat and rye seedlings were capable of identifying different Sb forms and demonstrated certain differences in the ability to uptake Sb and survive under high external Sb concentrations. An increase of Sb in the plants caused important variations in the concentrations of many essential nutrients.

Three decades of atmospheric metal deposition in Norway as evident from analysis of moss samples

Monitoring of atmospheric deposition of metals in Norway on a nationwide scale using samples of terrestrial moss started in 1977 and has been repeated every 5 years. This has facilitated a detailed record of temporal and spatial trends of metal deposition all over the country as a supplement to measurements based on bulk deposition sampling on a small number of sites. Pb, Zn, Cd, As, Sb, V, Sn, Mo, and Bi all show highest deposition in the far south due to trans-boundary pollution from other parts of Europe, but the contribution from long-range atmospheric transport to metal deposition has decreased substantially over the years. The distributions of Fe, Ni, Cu, Cr, and Co are more affected by local sources, but a decreasing time trend is also evident for these elements. Se is mainly derived from processes in the marine environment. Deposition of metals from Cu-Ni smelters in Russia situated close to the Norwegian border has shown a steadily increasing trend over the time period concerned.

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations (≥ 1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km × 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r(2) = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution.

Has the burden and distribution of PCBs and PBDEs changed in European background soils between 1998 and 2008? Implications for sources and processes

Background soils were collected from 70 locations on a latitudinal transect in the United Kingdom and Norway in 2008, ten years after they had first been sampled in 1998. The soils were analyzed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCs), to see whether there had been any change in the loadings or distributions of these persistent organic pollutants (POPs). The same transect has also been used to sample air between the mid-1990s and the present, so the air and soil spatial and temporal trends provide information on air-soil transfers, source-receptor relationships, long-range atmospheric transport (LRAT), and recycling phenomena. Comparisons of the 2008 and 1998 data sets show a general decline for PBDEs in surface soil, and a smaller averaged net decline of PCBs. Changes between the years were observed for total POP concentrations in soil and also for correlations with site and sample characteristics assumed to affect those concentrations. POP concentrations were correlated to distance and strength of possible sources, a relationship that became weaker in the 2008 data. Fractionation, a commonly discussed process for the global cycling of POPs was also lost in the 2008 data. As in 1998, soil organic matter content continues to have a strong influence on the loadings of POPs in surface soils, but changes in the PCB loads were noted. These factors indicate an approach to air-surface soil equilibrium and a lessening of the influence of primary sources on POP concentrations in soil between 1998 and 2008.

Mosses as biomonitors of atmospheric heavy metal deposition: spatial patterns and temporal trends in Europe

In recent decades, mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals. Since 1990, the European moss survey has been repeated at five-yearly intervals. Although spatial patterns were metal-specific, in 2005 the lowest concentrations of metals in mosses were generally found in Scandinavia, the Baltic States and northern parts of the UK; the highest concentrations were generally found in Belgium and south-eastern Europe. The recent decline in emission and subsequent deposition of heavy metals across Europe has resulted in a decrease in the heavy metal concentration in mosses for the majority of metals. Since 1990, the concentration in mosses has declined the most for arsenic, cadmium, iron, lead and vanadium (52-72%), followed by copper, nickel and zinc (20-30%), with no significant reduction being observed for mercury (12% since 1995) and chromium (2%). However, temporal trends were country-specific with sometimes increases being found.

Trends in European background air reflect reductions in primary emissions of PCBs and PBDEs

Data are presented for polychlorinated biphenyls (PCBs) and polybrominated diphenyls ethers (PBDEs) in passive air samplers (PAS) collected along a rural/remote latitudinal transect from southern UK to northern Norway during 2004-2008. This study is part of an ongoing campaign, using semipermeable membrane devices (SPMDs) as PAS over two year intervals since 1994. Absolute sequestered amounts of selected PCB congeners have decreased in a first order fashion between 1994-2008, with the average time of 8.4+/-3.2 years for atmospheric concentrations to decline by 50%. PCBs have continued to fractionate with latitude during this period. PBDE concentrations declined by 50% between 2000 and 2008 every 2.2+/-0.4 years. Results are discussed in terms of sources, long-range atmospheric transport, global fractionation, and clearance processes. It is concluded that the spatial and temporal trends in background European air mainly reflect the strength of primary diffusive emissions of these compounds and subsequently their ongoing declines. The direct evidence for this is similar rates of decline at all the sites; similar rates of decline for all congeners; no systematic change in the fractionation pattern since 1994. The latest results indicate a reduction in the rate of decline for PCBs (and hence in primary emissions).

Effects of experimental CO2 leakage on solubility and transport of seven trace metals in seawater and sediment

The impact of CO(2) leakage on solubility and distribution of trace metals in seawater and sediment has been studied in lab scale chambers. Seven metals (Al, Cr, Ni, Pb, Cd, Cu, and Zn) were investigated in membrane-filtered seawater samples, and DGT samplers were deployed in water and sediment during the experiment. During the first phase (16 days), "dissolved" (<0.2 microm) concentrations of all elements increased substantially in the water. The increase in dissolved fractions of Al, Cr, Ni, Cu, Zn, Cd and Pb in the CO(2) seepage chamber was respectively 5.1, 3.8, 4.5, 3.2, 1.4, 2.3 and 1.3 times higher than the dissolved concentrations of these metals in the control. During the second phase of the experiment (10 days) with the same sediment but replenished seawater, the dissolved fractions of Al, Cr, Cd, and Zn were partly removed from the water column in the CO(2) chamber. DNi and DCu still increased but at reduced rates, while DPb increased faster than that was observed during the first phase. DGT-labile fractions (Me(DGT)) of all metals increased substantially during the first phase of CO(2) seepage. DGT-labile fractions of Al, Cr, Ni, Cu, Zn, Cd and Pb were respectively 7.9, 2.0, 3.6, 1.7, 2.1, 1.9 and 2.3 times higher in the CO(2) chamber than that of in the control chamber. Al(DGT), Cr(DGT), Ni(DGT), and Pb(DGT) continued to increase during the second phase of the experiment. There was no change in Cd(DGT) during the second phase, while Cu(DGT) and Zn(DGT) decreased by 30% and 25%, respectively in the CO(2) chamber. In the sediment pore water, DGT labile fractions of all the seven elements increased substantially in the CO(2) chamber. Our results show that CO(2) leakage affected the solubility, particle reactivity and transformation rates of the studied metals in sediment and at the sediment-water interface. The metal species released due to CO(2) acidification may have sufficiently long residence time in the seawater to affect bioavailability and toxicity of the metals to biota.

Monitoring of trace element atmospheric deposition using dry and wet moss bags: accumulation capacity versus exposure time

To clarify the peculiarities of trace element accumulation in moss bags technique (active biomonitoring), samples of the moss Sphagnum girgensohnii Rusow were exposed in bags with and without irrigation for 15 days up to 5 months consequently in the semi-urban area of Belgrade (Serbia) starting from July 2007. The accumulation capacity for 49 elements determined by ICP-MS in wet and dry moss bags was compared. The concentration of some elements, i.e. Al, V, Cr, Fe, Zn, As, Se, Sr, Pb, and Sm increased continuously with exposure time in both dry and wet moss bags, whereas concentration of Na, Cl, K, Mn, Rb, Cs, and Ta decreased. Irrigation of moss resulted in a higher accumulation capacity for most of the elements, especially for Cr, Zn, As, Se, Br, and Sr. Principal component analysis was performed on the datasets of element concentrations in wet and dry moss bags for source identification. Results of the factor analysis were similar but not identical in the two cases due to possible differences in element accumulation mechanisms.

Soils and geomedicine

Geomedicine is the science dealing with the influence of natural factors on the geographical distribution of problems in human and veterinary medicine. Discussions on potential harmful impacts on human and animal health related to soil chemistry are frequently focused on soil pollution. However, problems related to natural excess or deficiency of chemical substances may be even more important in a global perspective. Particularly problems related to trace element deficiencies in soils have been frequently reported in agricultural crops as well as in livestock. Deficiencies in plants are often observed for boron, copper, manganese, molybdenum, and zinc. In animals deficiency problems related to cobalt, copper, iodine, manganese, and selenium are well known. Toxicity problems in animals exposed to excess intake have also been reported, e.g., for copper, fluorine, and selenium. Humans are similar to mammals in their relations to trace elements and thus likely to develop corresponding problems as observed in domestic animals if their supply of food is local and dependent on soils providing trace element imbalances in food crops. In large parts of Africa, Asia, and Latin America, people depend on locally grown food, and geomedical problems are common in these parts of the world. Well-known examples are Keshan disease in China associated with selenium deficiency, large-scale arsenic poisoning in Bangladesh and adjacent parts of India, and iodine deficiency disorders in many countries. Not all essential elements are derived only from the soil minerals. Some trace elements such as boron, iodine, and selenium are supplied in significant amounts to soils by atmospheric transport from the marine environment, and deficiency problems associated with these elements are therefore generally less common in coastal areas than farther inland. For example, iodine deficiency disorders in humans are most common in areas situated far from the ocean. There is still a great need for further research on geomedical problems.