<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.     

Endogenous <Emphasis Type="Italic">trans</Emphasis>-zeatin content in plants with different metal-accumulating ability: a field survey

A field survey was conducted to evaluate soil metal pollution and endogenous trans-zeatin content in the leaves of plants growing at six sites in a metal-polluted area located in Gejiu, Yunnan, China. Five plant species were collected, and the physicochemical properties and concentrations of five metals in the soil were analyzed. The trans-zeatin content in plant leaves was measured by high-performance liquid chromatography. Based on the Nemerow pollution index, the six sites were classified into four levels of pollution (i.e., low, medium, high, and severely high). The degree of soil metal pollution was cadmium (Cd) > arsenic (As) > lead (Pb) > zinc (Zn) > copper (Cu). The leaf trans-zeatin content in Pteris vittata (an arsenic hyperaccumulator) increased significantly by 98.6 % in soil with a severely high level of pollution compared with soil at a low level of pollution. However, in non-hyperaccumulators Bidens pilosa var. radiata and Ageratina adenophora, a significant decrease in leaf trans-zeatin content of 35.6 and 87.6 %, respectively, was observed. The leaf trans-zeatin content in Artemisia argyi also decreased significantly by 73.6 % in high metal-polluted soil compared with that in medium metal-polluted soil. Furthermore, significant correlations were observed between leaf trans-zeatin content in Pteris vittata and As, Pb, and Cd concentrations in the soil; however, either no correlation or a negative one was observed in the other plant species. Therefore, a high content of trans-zeatin in the leaves of Pteris vittata may play an important role in its normal growth and tolerance to metals.     

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.     

Enhanced UV-B and Elevated CO<Subscript>2</Subscript> Impacts Sub-Arctic Shrub Berry Abundance,Quality and Seed Germination

This study investigated the effects of long-term-enhanced UV-B, and combined UV-B with elevated CO₂ on dwarf shrub berry characteristics in a sub-arctic heath community. Germination of Vaccinium myrtillus was enhanced in seeds produced at elevated UV-B, but seed numbers and berry size were unaffected. Elevated UV-B and CO₂ stimulated the abundance of V. myrtillus berries, whilst UV-B alone stimulated the berry abundance of V. vitis-idaea and Empetrum hermaphroditum. Enhanced UV-B reduced concentrations of several polyphenolics in V. myrtillus berries, whilst elevated CO₂ increased quercetin glycosides in V. myrtillus, and syringetin glycosides and anthocyanins in E. hermaphroditum berries. UV-B × CO₂ interactions were found for total anthocyanins, delphinidin-3-hexoside and peonidin-3-pentosidein in V. myrtillus berries but not E. hermaphroditum. Results suggest positive impacts of UV-B on the germination of V. myrtillus and species-specific impacts of UV-B × elevated CO₂ on berry abundance and quality. The findings have relevance and implications for human and animal consumers plus seed dispersal and seedling establishment.     

Visible light photocatalytic antibacterial activity of Ni-doped and N-doped TiO<Subscript>2</Subscript> on <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> and <Emphasis Type="Italic">Escherichia coli</Emphasis> bacteria

The Ni-doped and N-doped TiO₂ nanoparticles were investigated for their antibacterial activities on Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria. Their morphological features and characteristics such as particle size, surface area, and visible light absorbing capacity were compared and discussed. Scanning electron microscopy, X-ray diffraction, and UV–visible spectrophotometry were used to characterize both materials. The inactivation of E. coli (as an example of Gram-negative bacteria) and S. aureus (as an example of Gram-positive bacteria) with Ni-doped and N-doped TiO₂ was investigated in the absence and presence of visible light. Antibacterial activity tests were conducted using undoped, Ni-doped, and N-doped TiO₂. The N-doped TiO₂ nanoparticles show higher antibacterial activity than Ni-doped TiO₂. The band gap narrowing of N-doped TiO₂ can induce more visible light absorption and leads to the superb antibacterial properties of this material. The complete inactivation time for E. coli at an initial cell concentration of 2.7?×?10⁴ CFU/mL was 420 min which is longer than the 360 min required for S. aureus inactivation. The rate of inactivation of S. aureus using the doped TiO₂ nanoparticles in the presence of visible light is greater than that of E. coli. The median lethal dose (LD50) values of S. aureus and E. coli by antibacterial activity under an 18-W visible light intensity were 80 and 350 mg/ml for N-doped TiO₂, respectively.     

Non-enhanced phytoextraction of cadmium,zinc, and lead by high-yielding crops

Heavy metal soil contamination from mining and smelting has been reported in several regions around the world, and phytoextraction, using plants to accumulate risk elements in aboveground harvestable organs, is a useful method of substantially reducing this contamination. In our 3-year experiment, we tested the hypothesis that phytoextraction can be successful in local soil conditions without external fertilizer input. The phytoextraction efficiency of 15 high-yielding crop species was assessed in a field experiment performed at the Litavka River alluvium in the P?íbram region of Czechia. This area is heavily polluted by Cd, Zn, and Pb from smelter installations which also polluted the river water and flood sediments. Heavy metal concentrations were analyzed in the herbaceous plants’ aboveground and belowground biomass and in woody plants’ leaves and branches. The highest Cd and Zn mean concentrations in the aboveground biomass were recorded in Salix x fragilis L. (10.14 and 343 mg kg^?1 in twigs and 16.74 and 1188 mg kg^?1 in leaves, respectively). The heavy metal content in woody plants was significantly higher in leaves than in twigs. In addition, Malva verticillata L. had the highest Cd, Pb, and Zn concentrations in herbaceous species (6.26, 12.44, and 207 mg kg^?1, respectively). The calculated heavy metal removal capacities in this study proved high phytoextraction efficiency in woody species; especially for Salix × fragilis L. In other tested plants, Sorghum bicolor L., Helianthus tuberosus L., Miscanthus sinensis Andersson, and Phalaris arundinacea L. species are also recommended for phytoextraction.     

Monitoring an outdoor smoking area by means of PM<Subscript>2.5</Subscript> measurement and vegetal biomonitoring

The extension of pollutant accumulation in plant leaves associated with its genotoxicity is a common approach to predict the quality of outdoor environments. However, this approach has not been used to evaluate the environmental quality of outdoor smoking areas. This study aims to evaluate the effects of environmental tobacco smoke (ETS) by assessing particulate matter 2.5 μm (PM_2.5) levels, the pollen abortion assay, and trace elements accumulated in plant leaves in an outdoor smoking area of a hospital. For this, PM_2.5 was measured by active monitoring with a real time aerosol monitor for 10 days. Eugenia uniflora trees were used for pollen abortion and accumulated element assays. Accumulated elements were also assessed in Tradescantia pallida leaves. The median concentration of PM_2.5 in the smoking area in all days of monitoring was 66 versus 34 μg/m³ in the control area (P?<?0.001). In addition, the elements Al, Cd, Cu, Ni, Pb, Rb, Sb, Se, and V in Tradescantia pallida and Al, Ba, Cr, Cu, Fe, Mg, Pb, and Zn in Eugenia uniflora were in higher concentration in the smoking area when compared to control area. Smoking area also showed higher rate of aborted grains (26.1?±?10.7 %) compared with control (17.6?±?4.5 %) (P?=?0.003). Under the study conditions, vegetal biomonitoring proved to be an effective tool for assessing ETS exposure in outdoor areas. Therefore, vegetal biomonitoring of ETS could be a complement to conventional analyses and also proved to be a cheap and easy-handling tool to assess the risk of ETS exposure in outdoor areas.     

Accumulation of heavy metals in native Andean plants: potential tools for soil phytoremediation in Ancash (Peru)

Metal contamination is a recurring problem in Peru, caused mainly by mine tailings from a past active mining activity. The Ancash region has the largest number of environmental liabilities, which mobilizes high levels of metals and acid drainages into soils and freshwater sources, posing a standing risk on human and environmental health. Native plant species spontaneously growing on naturally acidified soils and acid mine tailings show a unique tolerance to high metal concentrations and are thus potential candidates for soil phytoremediation. However, little is known about their propagation capacity and metal accumulation under controlled conditions. In this study, we aimed at characterizing nine native plant species, previously identified as potential hyperaccumulators, from areas impacted by mine tailings in the Ancash region. Plants were grown on mine soils under greenhouse conditions during 5 months, after which the concentration of Cd, Cu, Ni, Pb, and Zn was analyzed in roots, shoots, and soils. The bioaccumulation (BAF) and translocation factor (TF) were calculated to determine the amount of each metal accumulated in the roots and shoots and to identify which species could be better suited for phytoremediation purposes. Soil samples contained high Cd (6.50–49.80 mg/kg), Cu (159.50–1187.00 mg/kg), Ni (3.50–8.70 mg/kg), Pb (1707.00–4243.00 mg/kg), and Zn (909.00–7100.00 mg/kg) concentrations exceeding national environmental quality standards. After exposure to mine tailings, concentrations of metals in shoots were highest in Werneria nubigena (Cd, 16.68 mg/kg; Cu, 41.36 mg/kg; Ni, 26.85 mg/kg; Zn, 1691.03 mg/kg), Pennisetum clandestinum (Pb, 236.86 mg/kg), and Medicago lupulina (Zn, 1078.10 mg/kg). Metal concentrations in the roots were highest in Juncus bufonius (Cd, 34.34 mg/kg; Cu, 251.07 mg/kg; Ni, 6.60 mg/kg; Pb, 718.44 mg/kg) and M. lupulina (Zn, 2415.73 mg/kg). The greatest BAF was calculated for W. nubigena (Cd, 1.92; Cu, 1.20; Ni, 6.50; Zn, 3.50) and J. bufonius (Ni, 3.02; Zn, 1.30); BCF for Calamagrostis recta (Cd, 1.09; Cu, 1.80; Ni, 1.09), J. bufonius (Cd, 3.91; Cu, 1.79; Ni, 18.36), and Achyrocline alata (Ni, 137; Zn, 1.85); and TF for W. nubigena (Cd, 2.36; Cu, 1.70; Ni, 2.42; Pb, 1.17; Zn, 1.43), A. alata (Cd, 1.14; Pb, 1.94), J. bufonius (Ni, 2.72; Zn, 1.63), and P. clandestinum (Zn, 1.14). Our results suggest that these plant species have a great potential for soil phytoremediation, given their capability to accumulate and transfer metals and their tolerance to highly metal-polluted environments in the Andean region.     

Effects of organic acids on the photosynthetic and antioxidant properties and accumulations of heavy metals of <Emphasis Type="Italic">Melilotus officinalis</Emphasis> grown in Cu tailing

The effect of citric acid (CA), acetic acid (Ac), and ethylene diamine tetraacetic acid (EDTA) on the photosynthetic and antioxidant properties and the accumulation of some heavy metals (HMs) of Melilotus officinalis seedling growing in Cu mine tailings for 25 days were studied. Results showed that the formation of photosynthesizing cells of M. officinalis was inhibited by EDTA at 2 mmol/kg. Photosynthetic pigment contents under EDTA of 2 mmol/kg were reduced by 26, 40, and 19 %, respectively, compared to the control. The proline contents in aboveground and underground parts increased as the level of EDTA was enhanced. CA and Ac enhanced the activities of superoxide dismutase (SOD) and peroxidase (POD) in the aboveground parts and EDTA inhibited the activity of POD in the underground parts. The addition of CA promoted significantly the growth of M. officinalis, while the biomass decreased significantly under 2 mmol/kg EDTA. Cu contents in the aboveground parts treated with 0.5 and 2.0 mmol/kg EDTA reached 175.50 and 265.17 μg/g dry weight, respectively. Ac and EDTA treatments promoted Cd to translocate from root to aboveground parts. The result indicated that M. officinalis was a tolerant species of Cu tailing and can be used to remediate Cu contaminated environment, and rationally utilization of organic acids, especially EDTA, in the phytoremediation can improve the growth and metals accumulation of M. officinalis.     

Combined bioremediation of atrazine-contaminated soil by <Emphasis Type="Italic">Pennisetum</Emphasis> and <Emphasis Type="Italic">Arthrobacter</Emphasis> sp. strain DNS10

Strain DNS10 was isolated from the black soil collected from the northeast of China which had been cultivated with atrazine as the sole nitrogen source. Pennisetum is a common plant in Heilongjiang Province of China. The main objective of this paper was to evaluate the efficiency of plant–microbe joint interactions (Arthrobacter sp. DNS10 + Pennisetum) in atrazine degradation compared with single-strain and single-plant effects. Plant–microbe joint interactions degraded 98.10 % of the atrazine, while single strain and single plant only degraded 87.38 and 66.71 % after a 30-day experimental period, respectively. The results indicated that plant–microbe joint interactions had a better degradation effect. Meanwhile, we found that plant–microbe joint interactions showed a higher microbial diversity. The results of microbial diversity illustrated that the positive effects of cropping could improve soil microbial growth and activity. In addition, we planted atrazine-sensitive plants (soybean) in the soil after repair. The results showed that soybean growth in soil previously treated with the plant–microbe joint interactions treatment was better compared with other treatments after 20 days of growth. This was further proved that the soil is more conducive for crop cultivation. Hence, plant–microbe joint interactions are considered to be a potential tool in the remediation of atrazine-contaminated soil.     

Metal uptake capability of <Emphasis Type="Italic">Cyperus articulatus</Emphasis> L. and its role in mitigating heavy metals from contaminated wetlands

Wetland plants are biological filters that play an important role in maintaining aquatic ecosystem and can take up toxic metals from sediments and water. The present study investigated the seasonal variation in the accumulation potential of heavy metals by Cyperus articulatus in contaminated watercourses. Forty quadrats, distributed equally in 8 sites (six contaminated sites along Ismailia canal and two uncontaminated sites along the River Nile), were selected seasonally for sediment, water, and plant investigations. Autumn was the flourishing season of C. articulatus with the highest shoot density, length, and diameter as well as aboveground biomass, while summer showed the least growth performance. The photosynthetic pigments were markedly reduced under contamination stress. C. articulatus plants accumulated concentrations of most heavy metals, except Pb, in their roots higher than the shoots. The plant tissues accumulated the highest concentrations of Fe, Cd, Ni, and Zn during autumn, while Cu and Mn during spring, and Cr and Co during winter. It was found that Cd, Cu, Ni, Zn, Pb, and Co had seasonal bioaccumulation factor (BF) > 1 with the highest BF for Cd, Ni, and Zn during autumn, Co, Cu, and Pb in winter, spring, and summer, respectively. The translocation factor of most heavy metals, except Pb in spring, was <1 indicating potential phytostabilization of these metals. In conclusion, autumn is an ideal season for harvesting C. articulatus in order to monitor pollution in contaminated wetlands.     

Effects of sediment burial disturbance on macro and microelement dynamics in decomposing litter of <Emphasis Type="Italic">Phragmites australis</Emphasis> in the coastal marsh of the Yellow River estuary,China

From April 2008 to November 2009, a field decomposition experiment was conducted to investigate the effects of sediment burial on macro (C, N) and microelement (Pb, Cr, Cu, Zn, Ni, and Mn) variations in decomposing litter of Phragmites australis in the coastal marsh of the Yellow River estuary. Three one-off sediment burial treatments [no sediment burial (0 mm year^?1, S₀), current sediment burial (100 mm year^?1, S₁₀), and strong sediment burial (200 mm year^?1, S₂₀)] were laid in different decomposition sites. Results showed that sediment burials showed significant influence on the decomposition rate of P. australis, in the order of S₁₀ (0.001990 day^?1)?≈?S₂₀ (0.001710 day^?1)?>?S₀ (0.000768 day^?1) (p?<?0.05). The macro and microelement in decomposing litters of the three burial depths exhibited different temporal variations except for Cu, Zn, and Ni. No significant differences in C, N, Pb, Cr, Zn, and Mn concentrations were observed among the three burial treatments except for Cu and Ni (p?>?0.05). With increasing burial depth, N, Cr, Cu, Ni, and Mn concentrations generally increased, while C, Pb, and Zn concentrations varied insignificantly. Sediment burial was favorable for C and N release from P. australis, and, with increasing burial depth, the C release from litter significantly increased, and the N in litter shifted from accumulation to release. With a few exceptions, Pb, Cr, Zn, and Mn stocks in P. australis in the three treatments evidenced the export of metals from litter to environment, and, with increasing burial depth, the export amounts increased greatly. Stocks of Cu and Ni in P. australis in the S₁₀ and S₂₀ treatments were generally positive, evidencing incorporation of the two metals in most sampling times. Except for Ni, the variations of C, N, Pb, Cr, Cu, Zn, and Mn stocks in P. australis in the S₁₀ and S₂₀ treatments were approximated, indicating that the strong burial episodes (S₂₀) occurred in P. australis marsh in the future would have little influence on the stocks of these elements. With increasing burial depths, the P. australis was particularly efficient in binding Cu and Ni and releasing C, N, Pb, Cr, Zn, and Mn, implying that the potential eco-toxic risk of Pb, Cr, Zn, and Mn exposure might be very serious. This study emphasized the effects of different burials on nutrient and metal cycling and mass balance in the P. australis marsh of the Yellow River estuary.     

Tolerance of Japanese knotweed <Emphasis Type="Italic">s</Emphasis>.<Emphasis Type="Italic">l</Emphasis>. to soil artificial polymetallic pollution: early metabolic responses and performance during vegetative multiplication

The expansion of invasive Japanese knotweed s.l. is of particular concern because of its aptitudes to rapidly colonize diverse environments, especially anthropized habitats generally characterized by their pollution with heavy metals. Whether the presence of heavy metals impacts the performance traits of this plant is a central question to better understand its invasive properties, though no controlled approach to assess these effects was yet reported. In this aim, we undertook greenhouse experiments where rhizome fragments of Japanese knotweed s.l. (Fallopia japonica and Fallopia × bohemica) were grown during 1 and 3 months, in a soil pot artificially polluted or not with heavy metals added in mixture (Cd, Cr, Pb, Zn). Our results showed that (i) the presence of heavy metals delayed rhizome regeneration and induced lowered plant part weights but did not affect plant height after 3 months; (ii) the effect of metals on the metabolic profiles of belowground part extracts was only detectable after 1 month and not after 3 months of growth, though it was possible to highlight the effect of metals independently of time and genotype for root extracts, and torosachrysone seemed to be the most induced compound; and (iii) the hybrid genotype tested was able to accumulate relatively high concentrations of metals, over or close to the highest reported ones for this plant for Cr, Cd and Zn, whereas Pb was not accumulated. These findings evidence that the presence of heavy metals in soil has a low impact on Fallopia sp. overall performance traits during rhizome regeneration, and has a rather stimulating effect on plant growth depending on pollution level.     

Evaluation of the giant reed (<Emphasis Type="Italic">Arundo donax</Emphasis>) in horizontal subsurface flow wetlands for the treatment of recirculating aquaculture system effluent

Introduction

Two emergent macrophytes, Arundo donax and Phragmites australis, were established in experimental subsurface flow, gravel-based constructed wetlands (CWs) receiving untreated recirculating aquaculture system wastewater.

Materials and methods

The hydraulic loading rate was 3.75 cm day^?1. Many of the monitored water quality parameters (biological oxygen demand [BOD], total suspended solids [TSS], total phosphorus [TP], total nitrogen [TN], total ammoniacal nitrogen [TAN], nitrate nitrogen [NO₃], and Escherichia coli) were removed efficiently by the CWs, to the extent that the CW effluent was suitable for use on human food crops grown for raw produce consumption under Victorian state regulations and also suitable for reuse within aquaculture systems.

Results and discussion

The BOD, TSS, TP, TN, TAN, and E. coli removal in the A. donax and P. australis beds was 94%, 67%, 96%, 97%, 99.6%, and effectively 100% and 95%, 87%, 95%, 98%, 99.7%, and effectively 100%, respectively, with no significant difference (p?>?0.007) in performance between the A. donax and P. australis CWs. In this study, as expected, the aboveground yield of A. donax top growth (stems + leaves) (15.0?±?3.4 kg wet weight) was considerably more than the P. australis beds (7.4?±?2.8 kg wet weight). The standing crop produced in this short (14-week) trial equates to an estimated 125 and 77 t ?ha^?1 year^?1 biomass (dry weight) for A. donax and P. australis, respectively (assuming that plant growth is similar across a 250-day (September–April) growing season and a single-cut, annual harvest).

Conclusion

The similarity of the performance of the A. donax- and P. australis-planted beds indicates that either may be used in horizontal subsurface flow wetlands treating aquaculture wastewater, although the planting of A. donax provides additional opportunities for secondary income streams through utilization of the energy-rich biomass produced.

     

Physiological and biochemical responses of <Emphasis Type="Italic">Machilus ichangensis</Emphasis> Rehd. et Wils and <Emphasis Type="Italic">Taxus chinensis</Emphasis> (Pilger) Rehd. to elevated O<Subscript>3</Subscript> in subtropical China

Considerable researches have documented the negative effects of ozone on woody species in North America and Europe; however, little is known about how woody tree species respond to elevated O₃ in subtropical China, and most of the previous studies were conducted using pot experiment. In the present study, Machilus ichangensis Rehd. et Wils (M. ichangensis) and Taxus chinensis (Pilger) Rehd. (T. chinensis), evergreen tree species in subtropical China, were exposed to non-filtered air (NF), 100 nmol mol^?1 O₃ (E1) and 150 nmol mol^?1 O₃ (E2), in open-top chambers under field conditions from 21st March to 2nd November 2015. In this study, O₃ fumigation significantly reduced net photosynthesis rate (Pn) in M. ichangensis in the three measurements and in T. chinensis in the last measurement. Also, non-stomatal factors should be primarily responsible for the decreased Pn. O₃ fumigation-induced increase in malondialdehyde, superoxide dismutase, and reduced ascorbic acid levels indicated that antioxidant defense mechanism had been stimulated to prevent O₃ stress and repair the oxidative damage. Yet, the increase of antioxidant ability was not enough to counteract the harm of O₃ fumigation. Because of the decrease in CO₂ assimilation, the growth of the two tree species was restrained ultimately. The sensitivity of the two tree species to O₃ can be determined: M. ichangensis > T. chinensis. It suggests a close link between the rising O₃ concentrations and the health risk of some tree species in subtropics in the near future.     

Assessment of trace metal contamination in the sea cucumber (<Emphasis Type="Italic">Holothuria tubulosa</Emphasis>) and sediments from the Dardanelles Strait (Turkey)

This study was performed to determine the concentrations of some trace metals (Cd, Cu, Pb, Ni, Zn, and Fe) in Holothuria tubuosa (Gmelin, 1788) belonging to Echinoderm species and in sediments that they live at three different stations (Gelibolu, Umur Bey/Lapseki, and Dardanos) on Dardanelles Strait between April 2013 and March 2014. The mean trace metal concentrations determined in H. tubulosa and sediment were as follows: Cd 0.18 mg/kg, Cu 2.43 mg/kg, Pb 2.09 mg/kg, Ni 14.58 mg/kg, Zn 16.86 mg/kg, and Fe 73.46 mg/kg and Cd 0.70 mg/kg, Cu 5.03 mg/kg, Pb 14.57 mg/kg, Ni 27.15 mg/kg, Zn 54.52 mg/kg, and Fe 3779.9 mg/kg, respectively. It was detected that the statistical difference between trace metals determined seasonally in muscle tissue of H. tubulosa was significant (p?>?0.05). As a result of the study, it was detected that H. tubulosa is a bioindicator species in determining Ni trace metal in sediment. The results were compared to the limit values of National and International Food Safety, and it was detected that Cd and Ni concentrations measured in sediment were above LEL of Ni and Cd concentrations according to Sediment Quality Guidelines.     

Removal of PCBs in contaminated soils by means of chemical reduction and advanced oxidation processes

Although the chemical reduction and advanced oxidation processes have been widely used individually, very few studies have assessed the combined reduction/oxidation approach for soil remediation. In the present study, experiments were performed in spiked sand and historically contaminated soil by using four synthetic nanoparticles (Fe⁰, Fe/Ni, Fe₃O₄, Fe_3???x Ni _x O₄). These nanoparticles were tested firstly for reductive transformation of polychlorinated biphenyls (PCBs) and then employed as catalysts to promote chemical oxidation reactions (H₂O₂ or persulfate). Obtained results indicated that bimetallic nanoparticles Fe/Ni showed the highest efficiency in reduction of PCB28 and PCB118 in spiked sand (97 and 79 %, respectively), whereas magnetite (Fe₃O₄) exhibited a high catalytic stability during the combined reduction/oxidation approach. In chemical oxidation, persulfate showed higher PCB degradation extent than hydrogen peroxide. As expected, the degradation efficiency was found to be limited in historically contaminated soil, where only Fe⁰ and Fe/Ni particles exhibited reductive capability towards PCBs (13 and 18 %). In oxidation step, the highest degradation extents were obtained in presence of Fe⁰ and Fe/Ni (18–19 %). The increase in particle and oxidant doses improved the efficiency of treatment, but overall degradation extents did not exceed 30 %, suggesting that only a small part of PCBs in soil was available for reaction with catalyst and/or oxidant. The use of organic solvent or cyclodextrin to improve the PCB availability in soil did not enhance degradation efficiency, underscoring the strong impact of soil matrix. Moreover, a better PCB degradation was observed in sand spiked with extractable organic matter separated from contaminated soil. In contrast to fractions with higher particle size (250–500 and <500 μm), no PCB degradation was observed in the finest fraction (≤250 μm) having higher organic matter content. These findings may have important practical implications to promote successively reduction and oxidation reactions in soils and understand the impact of soil properties on remediation performance.     

Investigation of low-level <Superscript>242</Superscript>Pu contamination on nutrition disturbance and oxidative stress in <Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.

Plutonium associated with higher molecular weight molecules is presumed to be poorly mobile and hardly plant available. In our present study, we investigate the uptake and effects of Pu treatments on Solanum tuberosum plants in amended Hoagland medium at concentrations of [²⁴²Pu] = 100 and 500 nm, respectively. We found a direct proof of oxidative stress in the plants caused by these rather low concentrations. For the confirmation of oxidative stress, we explored the production of nitric oxide (NO) and hydrogen peroxide (H₂O₂) by epifluorescence microscopy. Oxidative stress markers like lipid peroxidation and superoxide radicals (O₂ ^??) are monitored through histochemical analysis. The biochemical parameters i.e. chlorophyll and carotenoids are measured as an indicator of cellular damage in the tested plants including the enzymatic parameters such as catalase and glutathione reductase. From our work, we conclude that Pu in low concentration has no significant effects on the uptake of many trace and macroelements. In contrast, the content of O₂ ^?? , malondialdehyde (MDA), and H₂O₂ increases with increasing Pu concentration in the solution, while the opposite effects was found for NO, catalase, and glutathione reductase. These findings prove that even low concentration of Pu regulates ROS production and generate oxidative stress in S. tuberosum L.     

Fate and transport of perfluoro- and polyfluoroalkyl substances including perfluorooctane sulfonamides in a managed urban water body

Transport and fate of perfluoro- and polyfluoroalkyl substances (PFASs) in an urban water body that receives mainly urban runoff was investigated. Water, suspended solids, and sediment samples were collected during the monsoon (wet) and inter-monsoon (dry) season at different sites and depths. Samples were analyzed for C7 to C12 perfluoroalkyl carboxylate homologues (PFCAs) (PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA), perfluorohexane, perfluorooctane, and 6:2-fluorotelomer sulfonate (PFHxS, PFOS, and 6:2FtS, respectively), perfluorooctane sulfonamide (FOSA), N-ethyl FOSA (sulfluramid), N-ethyl sulfonamidoethanol (N-EtFOSE), and N-methyl and N-ethyl sulfonamidoacetic acid (N-EtFOSAA and N-MeFOSAA, respectively). Concentrations in wet samples were only slightly higher. The sum total PFAS (ΣPFAS) concentrations dissolved in the aqueous phase and sorbed to suspended solids (SS) ranged from 107 to 253 ng/L and 11 to 158 ng/L, respectively. PFOA, PFOS, PFNA, PFHxS, and PFDA contributed most (approximately 90 %) to the dissolved ΣPFASs. N-EtFOSA dominated the particulate PFAS burden in wet samples. K _D values of PFOA and PFOS calculated from paired SS and water concentrations varied widely (1.4 to 13.7 and 1.9 to 98.9 for PFOA and PFOS, respectively). Field derived K _D was significantly higher than laboratory K _D suggesting hydrophobic PFASs sorbed to SS resist desorption. The ΣPFAS concentrations in the top sedimentary layer ranged from 8 to 42 μg/kg and indicated preferential accumulation of the strongly sorbing long-chain PFASs. The occurrence of the metabolites N-MeFOSAA, N-EtFOSAA and FOSA in the water column and sediments may have resulted from biological or photochemical transformations of perfluorooctane sulfonamide precursors while the absence of FOSA, N-EtFOSA and 6:2FtS in sediments was consistent with biotransformation.