Analysis of serpentinophytes from north-east of Portugal for trace metal accumulation--relevance to the management of mine environment

In north–east of Portugal, the serpentinized area is about 8000 ha with a characteristic geology and flora. The serpentine plant community and respective soils were analyzed to examine the trace metal budget in different tissues of the plants exhibiting resistance to trace metals. One hundred and thirty five plant species belonging to 39 families and respective soils have been analyzed for total Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Substantial amounts of Ni, Cr, Co and Mn were detected in plant tissues which are listed below: Ni: Alyssum serpyllifolium (38 105); Bromus hordeaceus (1467); Linaria spartea (492); Plantago radicata (140); Lavandula stoechas (118) and Cistus salvifolius (114); Cr: L. spartea (706.7); Ulmus procera (173.4); A. serpyllifolium (129.3); Cistus ladanifer (40.8); L. stoechas (29.5); P. radicata (27.81); Setariopsis verticillata (25.7); Plantago lanceolata (24); Digitalis purpurea (23.4); Logfia minima (23.1); Arenaria querioides (23); Hieracium peleteranum (22.7); Arenaria montana (14.5); Co: A. serpyllifolium (145.1); L. spartea (63.2); P. radicata (10.4); H. peleteranum (7.3); Lepidium heterophyllum (6.9); A. querioides (6.6); C. salvifolius (6.5); C. ladanifer (6.3); L. stoechas (6.1); Anthyllis lotoides (6.1); L. minima (6.1); Euphorbia falcata (5.7) and B. hordeaceus (5.6); Mn: A. serpyllifolium (830); L. spartea (339); L. stoechas (187.1); L. minima (182.7); Castanea sativa (125); Spergula pentandra (124); P. radicata (119); Cytisus striatus (115.4); Quercus pyrenaica (110); Teucrium scorodonia (109.4); Fraxinus vulgaris (109); Anthyllis sampaiana (108); Quercus ilex (108). The significance of serpentine flora, need for conservation of these fragile and environmentally invaluable plant resources for possible use for in situ remediation of metalliferous substrates are presented in this paper.     

The evaluation of stability during the composting of different starting materials: comparison of chemical and biological parameters

Three blends formed by: (i) food processing waste (CP(FP)), (ii) waste water sewage sludge (CP(WW)), and (iii) their mixture (CP(FP+WW)), blended with tree pruning as bulking agent, were composted over 3 months. During composting the blends were monitored for the main physical-chemical characteristics: temperature, oxygen saturation level (O(2)%), pH, total and volatile solids, total organic carbon, and organic nitrogen (N(org)). In addition to the main parameters, the dissolved organic carbon (DOC), the inorganic nitrogen and the Oxygen Uptake Rate (OUR) were monitored. All the mixtures easily reached a peak temperature around 70°C, related to the lowest O(2)%. After 90 d, CP(FP), CP(FP+WW), and CP(WW) showed an organic matter mineralization of 43%, 35% and 33%, respectively; CP(FP) fitted an exponential model while both CP(FP+WW), and CP(WW) fitted a logistic model. During composting an OUR reduction of 79%, 78% and 73% was registered in CP(FP), CP(FP+WW), and CP(WW), respectively; the OUR successfully fitted the adopted exponential model and well reflected the stabilization process in time. The N(org) recovery at the end of the process was positive only in CP(WW) (11.6%). The DOC significantly decreased during the composting process but did not successfully fit any model. The mineral nitrogen did not follow the typical pattern with NH(4)(+) disappearance and NO(3)(-) accumulation. Strong NO(3)(-) losses were evident in all blends, while NH(4)(+) accumulations were detectable only in CP(FP), and CP(FP+WW). The NH(4)(+)/NO(3)(-) ratio did not satisfactorily reflect the composting process over time. The comparison of the first order (exponential) and logistic (sigmoidal) models applied to the OUR and OM course highlights the role of mineral nitrogen as limiting factor during composting of the more stabilized sludge.     

Estrogenic and thyroid hormone activity of a series of hydroxy-polychlorinated biphenyls

A series of novel synthetic monohydroxy polychlorinated biphenyls (OH-PCBs) (5 trichloro-, 5 tetrachloro- and 5 pentachloro-compounds) have been characterized (1H and 13C NMR and high resolution MS) and their estrogenic and thyroid hormone activities assessed using a yeast two-hybrid assay, both with and without possible metabolic activation by rat liver S9 preparation. Moderate estrogenic activity was found for 2,3,4(')-trichlorobiphenyl-4-ol (compound 5) but this was eliminated when exposed to the S9 mix. 2,2('),3('),4,6-Pentachlorobiphenyl-3-ol (13) and 2('),3,3('),6-tetrachlorobiphenyl-4-ol (10) both showed weak estrogenicity in the absence of the S9 mix. The estrogenicity of compound (10) was enhanced 10-fold by exposure to S9 metabolic activation but that of compound (13) remained unchanged. 2('),4,5('),6-Tetrachlorobiphenyl-2-ol (6) showed strong thyroid hormonal activity (5% of that of T4) whereas 3('),4,6-trichlorobiphenyl-3-ol (4), compound (10) and 2,3('),4,5('),6-pentachlorobiphenyl-3-ol (14) showed moderate activity, and 2('),3,3('),5-tetrachlorobiphenyl-2-ol (8) and 3,3('),5,5('),6-pentachlorobiphenyl-2-ol (11) showed weak activity. The activity of (4) was eliminated by S9 metabolic activation whereas those of (6) and (14) were weakened and that of (10) remained unchanged.     

Diminution of migration of phthalic acid esters in tequila beverage by the year of production

Abstract

The presence of diethyl-phthalate (DEP), dibutyl-phthalate (DBP), butylbenzyl-phthalate (BBP), diethylhexyl-phthalate (DEHP) and diisononyl-phthalate (DINP) was determined in 295 tequila samples. They were grouped by age of maturation (white, aged, extra aged or ultra aged) and year of production (between 2013 and 2018). Gas Chromatography coupled with Mass Spectrometry was used for identification and quantification. The results showed that 65 samples (22% of the total) were phthalate free. DEP (0.13-0.27?mg/kg), BBP (0.05–2.91?mg/kg) and DINP (1.64–3.43?mg/kg) were detected in 11 (3.73%), 37 (12.54%) and 5 (1.69%) samples, respectively. But, these concentrations did not exceed the maximum permitted limits (MPL) of phthalates for alcoholic beverages. DBP (0.01–2.20?mg/kg) and DEHP (0.03–4.64?mg/kg) were detected in 96 (32.54%) and 224 (75.93%) samples, from them only 10 (3.39%) and 15 (5.08%) samples, respectively, exceeded the MPL for alcoholic beverages and they were few tequilas produced in the year 2014 or before. DEHP was the most frequent phthalate found in tequila and observed DEHP concentrations were 2-times higher in ultra aged tequilas compared to those in white tequilas. We concluded that all tequilas produced in 2015 and after, satisfied the international standards for these compounds.     

Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

Concentrations of methylmercury in invertebrates from wetlands of the Prairie Pothole Region of North America

Prairie wetlands may be important sites of mercury (Hg) methylation resulting in elevated methylmercury (MeHg) concentrations in water, sediments and biota. Invertebrates are an important food resource and may act as an indicator of MeHg exposure to higher organisms. In 2007-2008, invertebrates were collected from wetland ponds in central Saskatchewan, categorized into functional feeding groups (FFGs) and analyzed for total Hg (THg) and MeHg. Methylmercury and THg concentrations in four FFGs ranged from 0.2-393.5 ng · g(-1) and 9.7-507.1 ng · g(-1), respectively. Methylmercury concentrations generally increased from gastropods with significantly lower average MeHg concentrations compared to other invertebrate taxa. Surrounding land use (agricultural, grassland and organic agricultural) may influence MeHg concentrations in invertebrates, with invertebrate MeHg concentrations being higher from organic ponds (457.5 ± 156.7 ng · g(-1)) compared to those from grassland ponds (74.8 ± 14.6 ng · g(-1)) and ponds on agricultural lands (32.8 ± 6.2 ng · g(-1)).     

Visualisation of the complexity of EUSES

The interdependencies of parameters applied in the models of EUSES are visualised in a directed connectivity graph. The parameters (inputs, defaults, state variables, outputs) are represented by boxes (nodes) and their relations by lines (edges). The visualisation, on the one hand, clarifies the complexity of the models in EUSES and, on the other hand, creates an overview and transparency. The parameters’ relations to each other can be recognised faster, and the models can be better understood. The complexity was quantified by the number (variety), kind (substance parameter, physico-chemical parameter, concentration, other parameters), and depth (dimension) of the parameter and the number of relations (connectivity). The variety of EUSES (without the modelsSimple Treat andSimple Box whose interior structure is not documented and without the effect and risk characterisation) amounts to 466, the connectivity to 961, and the maximal dimension is 21.     

Mechanisms of biodegradation of dibenzoate plasticizers

Biodegradation mechanisms were elucidated for three dibenzoate plasticizers: diethylene glycol dibenzoate (D(EG)DB), dipropylene glycol dibenzoate (D(PG)DB), both of which are commercially available, and 1,6-hexanediol dibenzoate, a potential green plasticizer. Degradation studies were done using Rhodococcus rhodochrous in the presence of pure alkanes as a co-substrate. As expected, the first degradation step for all of these systems was the hydrolysis of one ester bond with the release of benzoic acid and a monoester. Subsequent biodegradation of the monobenzoates of diethylene glycol (D(EG)MB) and dipropylene glycol (D(PG)MB) was very slow, leading to significant accumulation of these monoesters. In contrast, 1,6-hexanediol monobenzoate was quickly degraded and characterization of the metabolites indicated that the biodegradation proceeded by way of the oxidation of the alcohol group to generate 6-(benzoyloxy) hexanoic acid followed by β-oxidation steps. This pathway was blocked for D(EG)MB and D(PG)MB by the presence of an ether function.The use of a pure hydrocarbon as a co-substrate resulted in the formation of another class of metabolites; namely the esters of the alcohols formed by the oxidation of the alkanes and the benzoic acid released by hydrolysis of the original diesters. These metabolites were biodegraded without the accumulation of any intermediates.     

Identification of highly brominated analogues of Q1 in marine mammals

Three novel halogenated organic compounds (HOCs) have been identified in the blubber of marine mammals from coastal New England with the molecular formulae C(9)H(3)N(2)Br(6)Cl, C(9)H(3)N(2)Br(7), and C(9)H(4)N(2)Br(5)Cl. They were identified using high and low resolution gas chromatography mass spectrometry (GCMS) and appear to be highly brominated analogues of Q1, a heptachlorinated HOC suspected to be naturally produced. These compounds were found in Atlantic white sided dolphin (Lagenorhynchus acutus), bottlenose dolphin (Tursiops truncatus), common dolphin (Delphinus delphis), Risso's dolphin (Grampus griseus), harbor porpoise (Phocoena phocoena), beluga whale (Delphinapterus leucas), fin whale (Balaenoptera physalus), grey seal (Halichoerus grypus), harp seal (Phoca groenlandica) and a potential food source (Loligo pealei) with concentrations as high as 2.7 microg/g (lipid weight). The regiospecificity of C(9)H(3)N(2)Br(6)Cl is suggestive of a biogenic origin. Debromination of C(9)H(3)N(2)Br(6)Cl may be significant in the formation of C(9)H(4)N(2)Br(5)Cl.     

Influence of metal ion on sorption of p-nitrophenol onto sediment in the presence of cetylpyridinium chloride

Heavy metals and surfactants have a significant effect on the sorption of organic contaminants. In this study, batch equilibrium experiments were carried out to investigate the influence of Pb(NO(3))(2) on the sorption of p-nitrophenol (PNP) onto sediments in the presence of cationic surfactant cetylpyridinium chloride (CPC). Results indicated that in the complex system containing PNP, Pb(NO(3))(2) and CPC, the sorption of PNP decreased with increasing concentration of Pb(NO(3))(2) due primarily to competing for adsorption sites. Likewise, partitioning of PNP in adsorbed surfactant layers and micelles decreased with increasing level of Pb(NO(3))(2). Moreover, the influence of different metal ions (Pb(2+), Cd(2+), Zn(2+)) was examined and results indicated that the presence of heavy metals inhibited the sorption of PNP in the order: Pb(2+)>Cd(2+)>Zn(2+). The competitive effect of the heavy metals was in agreement with the hydration energy and hydrated radius. The results are believed to provide a useful insight into describing the transport and fate of PNP in natural environments.     

Involvement of siderophores in the reduction of metal-induced inhibition of auxin synthesis in Streptomyces spp

Unlike synthetic metal chelators, microbe-assisted phytoremediation provides plants with natural metal-solubilizing chelators which do not constitute a potential source of environmental pollution. Concurrently with microbial chelators, plant growth promotion can be enhanced through bacterially-produced phytohormones. In this work, the simultaneous production of siderophores and auxins by Streptomyces was studied to gain insight for future application in plant growth and phytoremediation in a metal-contaminated soil. Standard auxin and siderophore detection assays indicated that all of the investigated Streptomyces strains can produce these metabolites simultaneously. However, Al(3+), Cd(2+), Cu(2+), Fe(3+) and Ni(2+), or a combination of Fe(3+) and Cd(2+), and Fe(3+) and Ni(2+) affected auxin production negatively, as revealed by spectrophotometry and gas chromatography-mass spectrometry. This effect was more dramatic in a siderophore-deficient mutant. In contrast, except for Fe, all the metals stimulated siderophore production. Mass spectrometry showed that siderophore and auxin-containing supernatants from a representative Streptomyces species contain three different hydroxamate siderophores, revealing the individual binding responses of these siderophores to Cd(2+) and Ni(2+), and thus, showing their auxin-stimulating effects. We conclude that siderophores promote auxin synthesis in the presence of Al(3+), Cd(2+), Cu(2+) and Ni(2+) by chelating these metals. Chelation makes the metals less able to inhibit the synthesis of auxins, and potentially increases the plant growth-promoting effects of auxins, which in turn enhances the phytoremediation potential of plants.     

Spectroscopic investigation of magnetite surface for the reduction of hexavalent chromium

The reduction of Cr(VI) to Cr(III) by magnetite in the presence of added Fe(II) was characterized through batch kinetic experiments and the effect of Fe(II) addition and pH were investigated in this study. The addition of Fe(II) into magnetite suspension improved the reductive capacity of magnetite. Eighty percent of Cr(VI) was reduced by magnetite (6.5 g l(-1)) with Fe(II) (80 mg l(-1)) within 1 h, while 60% of Cr(VI) was removed by magnetite only. However, the extent of improved reductive capacity of magnetite with Fe(II) was less than that predicted by the summation of each reduction capacity of magnetite and Fe(II). The reduction of Cr(VI) in the magnetite suspension with Fe(II) increased with the increase of molar ratio of Fe(II) to Cr(VI) (0.6, 1, 1.5, 2.3) in the range of 0-2.3 and with the decrease of pH in the range of pH 8.0-5.5. The speciation of chromium, iron, and oxygen on the surface of magnetite was investigated by X-ray photoelectron spectroscopy. Cr 2p3/2, Fe 2p3/2, and O 1s peaks were mainly observed at 576.7 and 577.8 eV, at 711.2 eV, and at 530.2 and 531.4 eV, respectively. The results indicates that Cr(III) and Fe(III) were the dominant species on the surface of magnetite after reaction and that the dominant species covered the magnetite surface and formed metal (oxy)hydroxide.     

Accumulation of nutrients in soils affected by perennial colonies of piscivorous birds with reference to biogeochemical cycles of elements

The accumulation of selected N, K, and P forms in soils within three perennial colonies of black cormorant (Phalacrocorax carbo sinensis) and grey heron (Ardea cinerea) located in northern and eastern Poland were investigated. Soil samples were collected beneath the nests from the most representative for each colony plots. Control samples were taken outside the colonies within sites adjacent to the nesting areas but not affected by bird excrement. From each genetic horizon (20 horizons) in soil profiles, a cumulative sample of about 25-30 kg of soil was taken for analysis. Nitrogen by Kjeldahl, ammonium ions (N(NH(4))), nitrates (N(NO(3))), exchangeable potassium (K(ex)), available potassium (K(av)), and available phosphorus (P(av)) were determined. The soils affected by birds demonstrated a very strong enrichment with N, K, and P in comparison to the control sites, especially in the topsoil horizons. The content of N(NH(4)) in individual soil horizons from the colonies was from 1.7 to 10.1 times higher than the respective control, N(NO(3)) from 2.9 to 215.7, K(ex) from 2.0 to 35.1, K(av) from 1.1 to 48.1, and P(av) in the range from 2.4 to 53.0 times. The highest increment of chemical elements was noticeable in the soils of territories inhabited by cormorants and the least in forest occupied by herons. Some relationships between soil texture and accumulation of biogenic nutrients were determined. Clay loam soil showed the greatest enrichment with analysed forms of elements with the exception of N(NH(4)).     

Effect of the cationic composition of sorption solution on the quantification of sorption-desorption parameters of heavy metals in soils

We obtained the sorption isotherms of Cd, Cu, Pb and Zn in clay, clay saline and organic soils. The distribution coefficients (K(d)) were determined in 0.02 eq l(-1) CaCl(2) and in a solution that simulated the soil solution cationic composition. The K(d) values greatly varied with the composition of the sorption solution and the initial metal concentration. The sorption experiments were complemented with the quantification of the extractable metal, to estimate the reversibility of metal sorption. The extraction yields depended on the metal-soil combination, and the initial metal concentration, showing no correlation with previous K(d) values. The effect of the solution composition in mobility predictions was estimated through a Retention Factor, defined as the ratio of the K(d) versus the extraction yield. Results showed that risk was over- or underestimated using the CaCl(2) medium in soils with a markedly different soil solution composition.     

Characteristics of leachate from pyrolysis residue of sewage sludge

The pyrolysis residue (SP) of sewage sludge (SS) produced at 500 degrees C was subjected to batch and column leaching tests to investigate the release of its organic and inorganic constituents and metals. For comparison, incineration ash (SI) obtained from a SS incinerator was also tested. Pyrolysis and incineration reduced organic matter of SS from 0.78 kg kg(-1)-dry SS to 0.16 and 0.01 kg kg(-1)-dry SS, respectively. Heavy metals remained in SP without being volatilized, although Cd and Pb were transferred into the off-gas during incineration. In the batch leaching test with the leaching liquid-to-solid mass ratio (L/S)=10, the pH of the SS, SP, and SI filtrates was 6.3, 7.9, and 11.0, respectively. The total organic carbon concentrations were in the order SS (877 l mg l(-1))>SP (99 mg l(-1))>SI (26 mg l(-1)). The SP and SI filtrates met the landfill standard for the Cd and Pb concentrations (<0.3 mg l(-1)). In the column tests, although the SP contained more organic matter than that of SI, its carbon discharge into the leachate under aerobic conditions was similar to that of SI under anaerobic conditions. The leaching of heavy metals, such as Cd, Cr, Pb, and Zn, was also suppressed in SP during the active decomposition of organic matter. We demonstrated that pyrolysis reduces the potential release of pollutants from sewage sludge in landfill, making it a promising method of treating sewage sludge before landfilling.     

Effects of nitrogen dioxide on biochemical and physiological characteristics of soybean

One month old soybean (Glycine max (L.) Merrill) cv. 'Williams' plants were exposed to nitrogen dioxide (NO2 at 0.1, 0.2, 0.3, and 0.5 microl liter(-1) and carbon filtered air (control), 7 h per day for five days, under controlled environment. Data were collected on net photosynthetic rate (PN), stomatal resistance (SR), and dark respiration rate (DR), immediately following the fifth day of exposure and 24 h after termination of exposure. Chlorophyll a (Ch a), chlorophyll b (Ch b), total chlorophyll (tot Ch) and foliar nitrogen (N) were measured before and after exposures. Growth characteristics--relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), and root shoot ratio (RSR) -- were computed for treated plants using standard growth equations. Increases of 18% and 23% in PN were observed immediately following exposure to 0.2 microl liter(-1) NO2 and after 24 h recovery period, respectively. With 0.5 microl liter(-1) NO2 treatment, reductions in PN of 23% and 50% were observed, immediately after exposure and following 24 h recovery, respectively. DR rates with 0.2 l liter(-1) treatment were higher than the control. Chlorophyll a and tot Ch showed significant reduction with 0.5 microl liter(-1) NO2 treatment. The percent reduction in Ch a and tot Ch with 0.5 microl liter(-1) NO2 were 45% and 47%, respectively. Increases in foliar nitrogen content after 0.2 and 0.3 microl liter(-1) NO2 treatments were 46% and 69%, respectively. Nitrogen dioxide at 0.5 microl liter(-1) reduced RGR and NAR by 47% and 51%, respectively. Leaf area ratio was 42% higher in 0.5 microl liter(-)1 NO2 treated plants, compared with the control; this increase was insufficient to compensate for the decrease in NAR resulting in a net decline in RGR. Nitrogen dioxide up to 0.2 microl liter(-1) increased PN and foliar-N content of soybean. With 0.5 microl liter(-1) NO2, significant decreases were observed in PN, leaf chlorophyll, foliar-N, NAR and RGR. Nitrogen dioxide up to 0.2 microl liter(-)1 has a favorable influence on overall growth characteristics of soybean; however, inhibitory effects were seen with NO2 treatment at 0.5 microl liter(-1).     

Assessment of the environmental significance of heavy metal pollution in surficial sediments of the River Po

The magnitude and ecological relevance of metal pollution of the middle Po river deriving from the River Lambro tributary was investigated by applying different (complementary) sediment quality assessment approaches: (1) comparisons of concentrations with regional reference data, and (2) comparisons with consensus-based sediment quality guidelines (SQGs), as well as by investigations of the partitioning patterns of target heavy metals (Cd, Cu, Ni, Pb, Zn). Total metal concentrations in the surficial sediments revealed significant pollution inputs on the whole river stretch investigated, with a distinct peak at the inlet of the River Lambro. Based on the geoaccumulation index of target heavy metals, the middle reach of River Po has to be considered as moderately polluted with Cd (1相似文献   

Effect of Pencycuron on Microbial Parameters of Waterlogged Soil

A laboratory study was conducted to monitor the effect of pencycuron [1-(4-chlorobenzyl)-1-cyclopentyl-3-phenylurea] on microbial parameters of alluvial (AL) soil (Typic udifluvent) and coastal saline (CS) soil (Typic endoaquept) under waterlogged condition. Pencycuron at field rate (FR), 2FR and 10FR affected the microbial biomass C (MBC), soil ergosterol content and fluorescein diacetate hydrolyzing activity (FDHA) differentially. The DCM amendment did not seem to have any counteractive effect on the toxicity of pencycuron on the microbial variables. The change in microbial metabolic quotient (qCO₂) and microbial respiration quotient (Q_R), indicated pencycuron induced disturbance at 10FR. Present study revealed that the metabolically activated microbial population was more suppressed compared to the dormant population.     

Effect of pencycuron on microbial parameters of waterlogged soil

A laboratory study was conducted to monitor the effect of pencycuron [1-(4-chlorobenzyl)-1-cyclopentyl-3-phenylurea] on microbial parameters of alluvial (AL) soil (Typic udifluvent) and coastal saline (CS) soil (Typic endoaquept) under waterlogged condition. Pencycuron at field rate (FR), 2FR and 10FR affected the microbial biomass C (MBC), soil ergosterol content and fluorescein diacetate hydrolyzing activity (FDHA) differentially. The DCM amendment did not seem to have any counteractive effect on the toxicity of pencycuron on the microbial variables. The change in microbial metabolic quotient (qCO2) and microbial respiration quotient (QR), indicated pencycuron induced disturbance at 10FR. Present study revealed that the metabolically activated microbial population was more suppressed compared to the dormant population.