Plant uptake of radionuclides in lysimeter experiments

The results of seven years lysimeter experiments to determine the uptake of 60Co, 137Cs and 226Ra into agricultural crops (endive, maize, wheat, mustard, sugarbeet, potato, Faba bean, rye grass) are described. The lysimeter consists of twelve monolithic soil profiles (four soil types and three replicates) and is located in Seibersdorf/Austria, a region with a pannonian climate (pronounced differences between hot and semi-arid summers and humid winter conditions, annual mean of precipitation: 517 mm, mean annual temperature: 9.8 degrees C). Besides soil-to-plant transfer factors (TF), fluxes were calculated taking into account biomass production and growth time. Total median values of TF's (dry matter basis) for the three radionuclides decreased from 226Ra (0.068 kg kg(-1)) to 137Cs (0.043 kg kg(-1)) and 60Co (0.018 kg kg(-1)); flux values exhibited the same ranking. The varying physical and chemical properties of the four experimental soils resulted in statistically significant differences in transfer factors or fluxes between the investigated soils for 137Cs and 226Ra, but not for 60Co. Differences in transfer between plant species and plant parts are distinct, with graminaceous species showing, on average, TF values 5.8 and 15 times lower than dicotyledonous species for 137Cs and 60Co, respectively. This pattern was not found for 226Ra. It can be concluded that 137Cs transfer is heavily influenced by soil characteristics, whilst the plant-specific factors are the main source of TF variability for 60Co. The variability of 226Ra transfer originates both from soil properties and plant species behaviour.     

Radionuclides in some edible and medicinal macrofungal species from Tara Mountain,Serbia

Edible and medicinal macrofungi used in human diet represent not only important sources of nutritive elements but toxic substances as well (heavy metals and radionuclides). Radioactivity levels of four radionuclides (⁴⁰K, ¹³⁷Cs, ²²⁶Ra, ²²⁸Ra) were determined in the basidiomata (fruiting bodies of a Basidiomycetes) of six lignicolous (Fomitopsis pinicola, Ganoderma applanatum, Hericium clathroides, Megacollybia platyphylla, Pluteus cervinus, Trametes gibbosa) and three mycorrhizal (Boletus luridus, Boletus sp. 1, Boletus sp. 2) species as well as their soil (wood) substrates by gamma spectrometry (high-resolution high-purity germanium (HPGe) detector). The aim was to investigate their ability for radionuclide absorption according to transfer factors (from soil and wood), to predict potential bioindicator species as well as species with potential risk for human use. Samples were taken during years 2011 and 2012, at two sites in forest ecosystem of Tara Mountain (Serbia). Observed concentration ranges per dry weight were as follows: 29–3,020 Bq/kg (⁴⁰K), 21.9–735 Bq/kg (¹³⁷Cs), 3–39 Bq/kg (²²⁶Ra), and 2.0–18 Bq/kg (²²⁸Ra). Obtained results indicate that the type of basidiome (fleshy/tough), most likely due to a different metabolic rate, has a very important role in radionuclide accumulation. The highest activity concentrations of all analyzed radionuclides were found in species with fleshy basidiomata—P. cervinus, H. clathroides, M. platyphylla, and Boletus species. A species-specific influence on radionuclide uptake was more prominent comparing to habitat differences and the role of fungal trophic mode. No significant variations were observed regarding radionuclide activity among the same fungal species from different sampling sites.     

Effects of municipal solid waste compost and mineral fertilizer amendments on soil properties and heavy metals distribution in maize plants (Zea mays L.)

Soil amendments based on crop nutrient requirements are considered a beneficial management practice. A greenhouse experiment with maize seeds (Zea mays L.) was conducted to assess the inputs of metals to agricultural land from soil amendments. Maize seeds were exposed to a municipal solid waste (MSW) compost (50 Mg ha⁻¹) and NPK fertilizer (33 g plant⁻¹) amendments considering N plant requirement until the harvesting stage with the following objectives: (1) determine the accumulation of total and available metals in soil and (2) know the uptake and ability of translocation of metals from roots to different plant parts, and their effect on biomass production. The results showed that MSW compost increased Cu, Pb and Zn in soil, while NPK fertilizer increased Cd and Ni, but decreased Hg concentration in soil. The root system acted as a barrier for Cr, Ni, Pb and Hg, so metal uptake and translocation were lower in aerial plant parts. Biomass production was significantly enhanced in both MSW and NPK fertilizer-amended soils (17%), but also provoked slight increases of metals and their bioavailability in soil. The highest metal concentrations were observed in roots, but there were no significant differences between plants growing in amended soil and the control soil. Important differences were found for aerial plant parts as regards metal accumulation, whereas metal levels in grains were negligible in all the treatments.     

Transfer characteristics of cadmium and lead from soil to the edible parts of six vegetable species in southeastern China

The transfer characteristics of Cd and Pb from soils to the edible parts of six vegetable species were calculated from plant and corresponding surface soil samples collected from the fields in Fujian Province, southeastern China. The soil-to-plant transfer factors (TF) calculated from both total and DTPA-extractable Cd and Pb in the soils decreased with increasing total or DTPA-extractable Cd and Pb, indicating that the TF values of Cd and Pb depend on the soil metal content. For most plants studied, there was a significant relation between the TF values and the corresponding soil metal concentrations (total or DTPA-extractable) that was best described by an exponential equation (y=axb). We recommend that the representative TF value for a given crop-metal system should be estimated from the regression models between the transfer factors and the corresponding soil metal concentrations and at a given soil metal concentration.     

Characteristics of volatile compound emission and odor pollution from municipal solid waste treating/disposal facilities of a city in Eastern China

Transfer station, incineration plant, and landfill site made up the major parts of municipal solid waste disposal system of S city in Eastern China. Characteristics of volatile compounds (VCs) and odor pollution of each facility were investigated from a systematic perspective. Also major index related to odor pollution, i.e., species and concentration of VCs, olfactory odor concentration, and theoretic odor concentration, was quantified. Oxygenated compounds and hydrocarbons were the most abundant VCs in the three facilities. Different chemical species were quantified, and the following average concentrations were obtained: transfer station, 54 VCs, 2472.47 μg/m³; incineration plant, 75 VCs, 33,129.25 μg/m³; and landfill site, 71 VCs, 1694.33 μg/m³. Furthermore, the average olfactory odor concentrations were 20,388.80; 50,677.50; and 4951.17, respectively. The highest odor nuisance was detected in the waste tipping port of the incineration plant. A positive correlation between the olfactory and chemical odor concentrations was found with R ² = 0.918 (n = 15, P < 0.01). The result shows odor pollution risk transfer from landfill to incineration plant when adopting thermal technology to deal with the non-source-separated waste. Strong attention thus needs to be paid on the enclosed systems in incineration plant to avoid any accidental odor emission.

     

Australian native plant species Carpobrotus rossii (Haw.) Schwantes shows the potential of cadmium phytoremediation

Many polluted sites are typically characterized by contamination with multiple heavy metals, drought, salinity, and nutrient deficiencies. Here, an Australian native succulent halophytic plant species, Carpobrotus rossii (Haw.) Schwantes (Aizoaceae) was investigated to assess its tolerance and phytoextraction potential of Cd, Zn, and the combination of Cd and Zn, when plants were grown in soils spiked with various concentrations of Cd (20–320 mg kg^?1 Cd), Zn (150–2,400 mg kg^?1 Zn) or Cd + Zn (20?+?150, 40?+?300, 80?+?600 mg kg^?1). The concentration of Cd in plant parts followed the order of roots > stems > leaves, resulting in Cd translocation factor (TF, concentration ratio of shoots to roots) less than one. In contrast, the concentration of Zn was in order of leaves > stems > roots, with a Zn TF greater than one. However, the amount of Cd and Zn were distributed more in leaves than in stems or roots, which was attributed to higher biomass of leaves than stems or roots. The critical value that causes 10 % shoot biomass reduction was 115 μg g^?1 for Cd and 1,300 μg g^?1 for Zn. The shoot Cd uptake per plant increased with increasing Cd addition while shoot Zn uptake peaked at 600 mg kg^?1 Zn addition. The combined addition of Cd and Zn reduced biomass production more than Cd or Zn alone and significantly increased Cd concentration, but did not affect Zn concentration in plant parts. The results suggest that C. rossii is able to hyperaccumulate Cd and can be a promising candidate for phytoextraction of Cd from polluted soils.     

<Emphasis Type="Italic">Ailanthus Altissima</Emphasis> and <Emphasis Type="Italic">Phragmites Australis</Emphasis> for chromium removal from a contaminated soil

The comparative effectiveness for hexavalent chromium removal from irrigation water, using two selected plant species (Phragmites australis and Ailanthus altissima) planted in soil contaminated with hexavalent chromium, has been studied in the present work. Total chromium removal from water was ranging from 55 % (Phragmites) to 61 % (Ailanthus). After 360 days, the contaminated soil dropped from 70 (initial) to 36 and 41 mg Cr/kg (dry soil), for Phragmites and Ailanthus, respectively. Phragmites accumulated the highest amount of chromium in the roots (1910 mg Cr/kg_{(dry tissue)}), compared with 358 mg Cr/kg_{(dry tissue)} for Ailanthus roots. Most of chromium was found in trivalent form in all plant tissues. Ailanthus had the lowest affinity for Cr^VI reduction in the root tissues. Phragmites indicated the highest chromium translocation potential, from roots to stems. Both plant species showed good potentialities to be used in phytoremediation installations for chromium removal.     

Arsenic distribution in soils and plants of an arsenic impacted former mining area

A mining area affected by the abandoned exploitation of an arsenical tungsten deposit was studied in order to assess its arsenic pollution level and the feasibility of native plants for being used in phytoremediation approaches. Soil and plant samples were collected at different distances from the polluting sources and analysed for their As content and distribution. Critical soil total concentrations of As were found, with values in the range 70-5330 mg kg⁻¹ in the uppermost layer. The plant community develops As tolerance by exclusion strategies. Of the plant species growing in the most polluted site, the shrubs Salix atrocinerea Brot. and Genista scorpius (L.) DC. exhibit the lowest bioaccumulation factor (BF) values for their aerial parts, suggesting their suitability to be used with revegetation purposes. The species Scirpus holoschoenus L. highlights for its important potential to stabilise As at root level, accumulating As contents up to 3164 mg kg⁻¹.     

Leaves of higher plants as biomonitors of radionuclides (137Cs, 40K, 210Pb and 7Be) in urban air

Leaves of linden (Tilia tomentosa L. and Tilia cordata Mill.) and horse chestnut (Aesculus hippocastanum L.) were analysed as biomonitors of radionuclides in urban air. Samples of soils, leaves and aerosols were collected in Belgrade, Serbia. Activities of ¹³⁷Cs, ⁴⁰K, ²¹⁰Pb and ⁷Be in the samples were measured on an HPGe detector by standard gamma spectrometry. “Soil-to-leaves” transfer factors were calculated. Student’s t test and linear Pearson correlation coefficients were used for statistical analysis. Differences in local conditions at the sampling sites were not significant, and the mechanisms of the radionuclides’ accumulation in both plant species are similar. Ceasium-137 was detected in some of the leaf samples only. Transfer factors for ¹³⁷Cs and ⁴⁰K were (0.03–0.08) and 1.3, respectively. The concentrations of ²¹⁰Pb and ⁷Be in leaves were higher in autumn than in spring, and there were some similarities in their seasonal patterns in leaves and in air. Weak to medium correlation was obtained for the ²¹⁰Pb and ⁷Be activities in leaves and aerosols. Large positive correlation was obtained for the ²¹⁰Pb activities in linden leaves and the mean activity in aerosols for the preceding months. Different primary modes of radionuclides accumulation in leaves were observed. Since large positive correlation was obtained for the ²¹⁰Pb activity in linden leaves and the mean in aerosols for the preceding months, mature linden leaves could be used as biomonitors of recent ²¹⁰Pb activity in air.     

Correlation of foliar MT2b expression with Cd and Zn concentrations in hybrid aspen (Populus tremula × tremuloides) grown in contaminated soil

Metal uptake and its effect on foliar metallothionein 2b (MT2b) mRNA levels were studied in hybrid aspen (Populus tremula × tremuloides) in field conditions. The trees were planted on a site contaminated with several metals, including cadmium (mean 5.1 mg kg⁻¹), chromium (80 mg kg⁻¹), copper (180 mg kg⁻¹), nickel (81 mg kg⁻¹), vanadium (240 mg kg⁻¹) and zinc (520 mg kg⁻¹). Of the ten trace elements analyzed, only Cd and Zn accumulated in the leaves with maximal foliar concentrations of 35 and 2400 mg kg⁻¹ (dry weight), respectively. There was a strong correlation between Cd and Zn concentrations and bioaccumulation factors (concentration in plant/soil) in the leaves, branches and roots, suggesting similar transport mechanisms for these two metals. The levels of MT2b correlated with Cd and Zn concentrations in the leaves, demonstrating that increased MT2b expression is one of the responses of hybrid aspen to chronic metal exposure.     

Impact of temperature on the dynamics of organic matter and on the soil-to-plant transfer of Cd,Zn and Pb in a contaminated agricultural soil

Predicting the soil-to-plant transfer of metals in the context of global warming has become a major issue for food safety. It requires a better understanding of how the temperature alters the bioavailability of metals in cultivated soils. This study focuses on one agricultural soil contaminated by Cd, Zn and Pb. DGT measurements were performed at 10, 20 and 30 °C to assess how the bioavailability of metals was affected by a rise in soil temperature. A lettuce crop was cultivated in the same conditions to determine if the soil-to-plant transfer of metals increased with a rise in soil temperature. A gradual decline in Cd and Zn bioavailability was observed from 10 to 30 °C, which was attributed to more intense complexation of metals in the pore water at higher temperatures. Together with its aromaticity, the affinity of dissolved organic matter (DOM) for metals was indeed suspected to increase with soil temperature. One main output of the present work is a model which satisfactorily explains the thermal-induced changes in the characteristics of DOM reported in Cornu et al. (Geoderma 162:65–70, 2011) by assuming that the mineralization of initial aliphatic compounds followed a first-order reaction, increased with soil temperature according to the Arrhenius law, and due to a priming effect, led to the appearance of aromatic molecules. The soil-to-plant transfer of Cd and Zn was promoted at higher soil temperatures despite a parallel decrease in Cd and Zn bioavailability. This suggests that plant processes affect the soil-to-plant transfer of Cd and Zn the most when the soil temperature rises.     

Exposure of Brassica juncea (L) to arsenic species in hydroponic medium: comparative analysis in accumulation and biochemical and transcriptional alterations

Arsenic (As) contamination in the environment has attracted considerable attention worldwide. The objective of the present study was to see the comparative effect of As species As(III) and As(V) on accumulation, biochemical responses, and gene expression analysis in Brassica juncea var. Pusa Jaganath (PJn). Hydroponically grown 14-day-old seedlings of B. juncea were treated with different concentrations of As(III) and As(V). Accumulation of total As increased with increasing concentration of both As species and exposure time, mainly in roots. Reduction in seed germination, root–shoot length, chlorophyll, and protein content were observed with increasing concentration and exposure time of both As species, being more in As(III)-treated leaves. PJn variety showed that antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX)) and stress-related parameters (cysteine, proline, and malondialdehyde (MDA)) were stimulated and allows plant to tolerate both As species. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis in leaves showed significant changes in protein profile with more stringent effect with As(III) stress. Semiquantitative RT-PCR analysis showed regulation in expression of phytochelatin synthase (PCS), metallothionine-2 (MT-2), glutathione reductase (GR), and glutathione synthetase (GS) genes under both As(III) and As(V) stresses. Results suggested that accumulation and inhibition on physiological parameters differ according to the As species, while molecular and biochemical parameters showed a combinatorial type of tolerance mechanism against As(III) and As(V) stresses.     

Cadmium tolerance in six poplar species

Selection of poplar species with greater Cd tolerance and exploiting the physiological mechanisms involved in Cd tolerance are crucial for application of these species to phyto-remediation. The aim of this study is to investigate variation in Cd tolerance among the six poplar species and its underlying physiological mechanisms. Cuttings of six Populus species were cultivated for 10 weeks before exposure to either 0 or 200 μM CdSO₄ for 20 days. Gas exchange in mature leaves was determined by a portable photosynthesis system. Cd concentrations in tissues were analyzed by a flame atomic absorbance spectrometry. Subsequently, Cd amount per plant, bio-concentration factor (BCF) and translocation factor (T _f) were calculated. Nonenzymatic compounds and activities of antioxidative enzymes in tissues were analyzed spectrophotometrically. Cd exposure caused decline in photosynthesis in four poplar species including Populus cathayana (zhonghua 1). Among the six species, P. cathayana (zhonghua 1) displayed the highest Cd concentrations in tissues, the largest Cd amount in aerial parts, the highest BCF in aerial parts and T _f under Cd exposure. Under Cd stress, increases in total soluble sugars in roots but decreases in starch in roots, wood, and leaves of P. cathayana (zhonghua 1) were found. Induced O ₂ ^?? and H₂O₂ production in roots and leaves, and increases in free proline, soluble phenolics, and activities of antioxidative enzymes were observed in P. cathayana (zhonghua 1). Based on results of this pot experiment, it is concluded that P. cathayana (zhonghua 1) is superior to other five species for Cd phyto-remediation, and its well-coordinated physiological changes under Cd exposure confer the great Cd tolerance of this species.     

Heavy metal bioaccumulation in selected medicinal plants collected from Khetri copper mines and comparison with those collected from fertile soil in Haridwar,India

Heavy metal distribution in medicinal plants is gaining importance not only as an alternative medicine, but also for possible concern due to effects of metal toxicity. The present study has been focused on emphasizing the heavy metal status and bioaccumulation factors of V, Mn, Fe, Co, Cu, Zn, Se (essential metals) and Cr, Ni, Cd, As and Pb (potentially toxic metals) in medicinal plants grown under two different environmental conditions e.g., near to Khetri copper mine and those in fertile soils of Haridwar, both in India, using Instrumental Neutron Activation Analysis (relative method) and Atomic Absorption Spectrometry. The copper levels in the medicinal plants from Khetri were found to be 3-4 folds higher (31.6–76.5 mg kg^?1) than those from Haridwar samples (7.40–15.3 mg kg^?1), which is correlated with very high copper levels (763 mg kg^?1) in Khetri soil. Among various heavy metals, Cr (2.60–5.92 mg kg^?1), Cd (1.47–2.97 mg kg^?1) and Pb (3.97–6.63 mg kg^?1) are also higher in concentration in the medicinal plants from Khetri. The essential metals like Mn (36.4–69.3 mg kg^?1), Fe (192–601 mg kg^?1), Zn (24.9–49.9 mg kg^?1) and Se (0.13–0.91 mg kg^?1) and potentially toxic metals like Ni (3.09–9.01 mg kg^?1) and As (0.41–2.09 mg kg^?1) did not show much variations in concentration in the medicinal plants from both Khetri and Haridwar. The medicinal plants from Khetri, e.g., Ocimum sanctum, Cassia fistula, Withania somnifera and Azadirachta Indica were found rich in Ca and Mg contents while Aloe barbadensis showed moderately high Ca and Mg. Higher levels of Ca-Mg were found to correlate with Zn (except Azadirachta Indica). The bioaccumulation factors (BAFS) of the heavy metals were estimated to understand the soil-to-plant transfer pattern of the heavy metals. Significantly lower BAF values of Cu and Cr were found in the medicinal plants from Khetri, indicating majority fraction of these metals are precipitated and were immobilized species unsuitable for plant uptake. Overall, Withania somnifera (Ashwagandha) showed very high metal bioaccumulation.     

Carbon isotope analysis for source identification of atmospheric formaldehyde and acetaldehyde in Dinghushan Biosphere Reserve in South China

Formaldehyde and acetaldehyde are two most abundant carbonyls in ambient air. Biogenic emission has been proposed as a significant source other than anthropogenic emissions and atmospheric secondary formation. Here at a forest site in South China, the carbon isotopic compositions of formaldehyde and acetaldehyde emitted from leaves of three tree species (Litsea rotundifolia, Canarium album and Castanea henryi) were measured in comparison with the bulk carbon isotopic compositions of tree leaves. δ¹³C data of the emitted aldehydes (from ?31‰ to ?46‰) were quite different for tree species, which were all more depleted in ¹³C than the tree-leaf bulk δ¹³C values (from ?27‰ to ?32‰). Formaldehyde in ambient air at the forest site had δ¹³C values different from those of leaf-emitted formaldehyde, indicating other sources for ambient formaldehyde apart from direct emission from leaves, most probably the photooxidation of biogenic hydrocarbon like isoprene and monoterpene. The δ¹³C differences of acetaldehyde between ambient data and those of tree leaves emission were less than 1‰, implying direct biogenic emission as the dominant source.     

Radiometric and environmental impacts of mill tailings at experimental plant processing unit,Allouga, Egypt

Abstract

Uranium mining and ore processing are known to be harmful to the environment and human health if the waste generated is not managed properly. The aim of the present study is to determine the radiological indices in the mill tailings and review the possible attempts to utilize and minimize its hazardous effect. The activity concentrations of natural radionuclides, ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K have been measured by gamma spectrometry using HP-Ge detector. The average activity concentrations of ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K in the tailings wastes were 2071.8, 59.92, 6921.262, and 445. 57?Bq/kg respectively which are higher than the international average limit. The ranges of hazard indices such as Radium equivalent activity (Ra_eq), external hazard index (H_ex), internal hazard index (H_in), γ-radiation hazard index I_γ, Dose rate (nGy/h) and annual effective dose equivalent (AED), were estimated. Uraniumm isotopic ratios in the ore –material and mill tailing samples indicate migration out of radionuclides to the surrounding environment causing contamination and many dangerous diseases. Fairly, all investigated tailing waste samples do not satisfy the universal standards, the studied wastes relatively still have high uranium contents and need reprocessing.     

Volatile organic compounds (VOCs) emitted from 40 Mediterranean plant species:: VOC speciation and extrapolation to habitat scale

Forty native Mediterranean plant species were screened for emissions of the C5 and C10 hydrocarbons, isoprene and monoterpenes, in five different habitats. A total of 32 compounds were observed in the emissions from these plants. The number of compounds emitted by different plant species varied from 19 (Quercus ilex) to a single compound emission, usually of isoprene. Emission rates were normalised to generate emission factors for each plant species for each sampling event at standard conditions of temperature and light intensity. Plant species were categorised according to their main emitted compound, the major groups being isoprene, α-pinene, linalool, and limonene emitters. Estimates of habitat fluxes for each emitted compound were derived from the contributing plant species’ emission factors, biomass and ground cover. Emissions of individual compounds ranged from 0.002 to 505 g ha⁻¹ h⁻¹ (camphene from garrigue in Spain in autumn and isoprene from riverside habitats in Spain in late spring; respectively). Emissions of isoprene ranged from 0.3 to 505 g ha⁻¹ h⁻¹ (macchia in Italy in late spring and autumn; and riverside in Spain in late spring; respectively) and α-pinene emissions ranged from 0.51 to 52.92 g ha⁻¹ h⁻¹ (garrigue in Spain in late spring; and forest in France in autumn; respectively). Habitat fluxes of most compounds in autumn were greater than in late spring, dominated by emissions from Quercus ilex, Genista scorpius and Quercus pubescens. This study contributes to regional emission inventories and will be of use to tropospheric chemical modellers.     

Variable emissions of microbial volatile organic compounds (MVOCs) from root-associated fungi isolated from Scots pine

Soils emit a large variety of volatile organic compounds. In natural ecosystems, measurements of microbial volatile organic compound (MVOC) exchange rates between soil and atmosphere are difficult due to e.g. the spatial heterogeneity of the belowground organisms, and due to the many potential sources for the same compounds. We measured in laboratory conditions the MVOC emission rates and spectra of eight typical fungi occurring in boreal forest soils. The studied species are decomposers (Gymnopilus penetrans, Ophiostoma abietinum), ectomycorrhizal (Cenococcum geophilum, Piloderma olivaceum, Suillus variegatus, Tomentellopsis submollis) and endophytic fungi (Meliniomyces variabilis, Phialocephala fortinii). The MVOC emissions contained altogether 21 known and 6 unidentified compounds whose emission rates were >0.1 μg g(DW)^?1 h^?1. The most abundant compounds were the short-chain carbonyl compounds (acetone and acetaldehyde). The greatest carbonyl emissions were measured from P. olivaceum (1.9 mg acetone g(DW)^?1 h^?1) and P. fortinii (0.114 mg acetaldehyde g(DW)^?1 h^?1). Terpenoid emissions (isoprene, mono- and sesquiterpenes) were detected from some fungal cultures, but in relatively small amounts. We conclude that soil micro-organisms can potentially be responsible for significant emissions of volatiles, especially short-chain oxygenated compounds, to the below-canopy atmosphere.     

Measurements of β and α hexachlorocyclohexane in <Emphasis Type="Italic">Juglans regia</Emphasis> and <Emphasis Type="Italic">Prunus spinosa</Emphasis> trees in a contaminated area,central Italy

Vegetables play an important role in the human diet, and the transfer of toxic contaminants from the soil to plants has been little studied for most tree species and their edible portions. In an area affected by hexachlorocyclohexane (HCH) contamination, in the Sacco River Valley (central Italy), measurements of β- and α-HCH isomers were made on different parts of two tree species: Juglans regia and Prunus spinosa. Concentrations were analysed in roots, branches, leaves, fruits, and seeds. A spatial evaluation of the results highlighted an inverse association of contamination with distance from the river, which is the main route of transport in the environment. Results in J. regia showed decreasing values in this order: branches > leaves > husks > nutmeat. Results in P. spinosa showed decreasing values in the following order: branches > leaves > fruits. In J. regia, nutmeat values were all below limit of detection (LOD, 0.0005 mg/kg), except in one case in which a very low concentration of β-HCH was found (0.006 mg/Kg), compliant with maximum residue limits (MRLs). The ability of J. regia to store large quantities of β-HCH in wooden and leafy parts but not in edible kernels makes this plant a potential and precious tool in remediation and economical reconversion of polluted areas. It is also valuable for food and wood manufacturing.     

Phytoextraction of rare earth elements in herbaceous plant species growing close to roads

The aim of study was to determine the phytoextraction of rare earth elements (REEs) to roots, stems and leaves of five herbaceous plant species (Achillea millefolium L., Artemisia vulgaris L., Papaver rhoeas L., Taraxacum officinale and Tripleurospermum inodorum), growing in four areas located in close proximity to a road with varied traffic intensity. Additionally, the relationship between road traffic intensity, REE concentration in soil and the content of these elements in plant organs was estimated. A. vulgaris and P. rhoeas were able to effectively transport REEs in their leaves, independently of area collection. The highest content of REEs was observed in P. rhoeas leaves and T. inodorum roots. Generally, HREEs were accumulated in P. rhoeas roots and leaves and also in the stems of T. inodorum and T. officinale, whereas LREEs were accumulated in T. inodorum roots and T. officinale stems. It is worth underlining that there was a clear relationship between road traffic intensity and REE, HREE and LREE concentration in soil. No positive correlation was found between the concentration of these elements in soil and their content in plants, with the exception of T. officinale. An effective transport of REEs from the root system to leaves was observed, what points to the possible ability of some of the tested plant species to remove REEs from soils near roads.