Interaction of contaminated sediment from a salt marsh with estuarine water: evaluation by leaching and ecotoxicity assays and salts from leachate evaporation

Purpose

Wastes from a former Portuguese steel plant were deposited between 1961 and 2001 on the riverbank of a tributary of the Tagus River creating a landfill connected to the river, posing a potential contamination risk to the Tagus estuary ecosystem. This study aims to assess the transfer of chemical elements from contaminated sediments to the estuarine water from cycles of sediment leaching so as to evaluate the ecotoxicity of the leachates, and to analyze the solid phases crystallized from those leachates.

Materials and methods

Landfill sediment and estuarine water samples were collected during low tide. Sediment samples were analyzed for pH, electric conductivity (EC), C_org, NPK, and iron oxides. Leaching assays (four replicates) were done using estuarine water (200 cm³/replicate) and 1.5 kg of sediment per reactor. Each reactor was submitted to four leaching processes (0, 28, 49, and 77 days). The sediment was kept moist between leaching processes. Sediment (total (acid digestion) and available fraction (diluted organic acid extraction-Rhizo)) elemental concentrations were determined by inductively coupled plasma–instrumental neutron activation analysis (ICP/INAA). Leachates, and estuarine and sediment pore waters were analyzed for metals/metalloids by ICP/mass spectrometry (MS) and carbonates/sulfate/chloride by standard methodologies. Ecotoxicity assays were performed in leachates and estuarine and pore waters using Artemia franciscana and Brachionus plicatillis. Aliquots of the leachates were evaporated to complete dryness (23–25 °C) and crystals analyzed by X-ray powder diffraction (XRD).

Results and discussion

Sediment with pH?=?8 and high EC and C_org was contaminated with As, Cd, Cr, Cu, Pb, and Zn. The element concentrations in the available fraction of the sediment were low compared to the sediment total concentrations (<1 % for Rhizo extraction). The concentrations of potentially hazardous elements in the estuarine water were relatively low, except for Cd. Concentrations of hazardous elements in the leachates were very low. Calcium, K, Mg, Na, and chloride concentrations were high but did not vary significantly among the four leaching experiments. Total concentrations of carbonate were much higher in leachates than in estuarine water. Both estuarine water and leachates showed negligible toxicity. Crystals identified in the solids obtained from the leachates by evaporation were halite, anhydrite, epsomite, dolomite, and polyhalite.

Conclusions

The sediment showed the capacity to retain the majority of the potentially hazardous chemical elements. Remobilization of chemical elements from sediment by leaching was essentially negligible. The variation of total concentrations of Ca, carbonate, and sulfate in leachates indicates that the sediment contained reactive sulfides. Due to its composition, the sediment seems to be a dynamic system of pollution control, which should not be disturbed.

     

Essential oils from plants and in vitro shoots of Hypericum androsaemum L

The essential oil yields obtained by hydrodistillation of the aerial parts of Hypericum androsaemum cultivated plants varied from 0.94 to 4.09 mg/g of biomass dry weight, depending of the harvest time. The respective analyses performed by gas chromatography and gas chromatography-mass spectrometry revealed more than 80 compounds, 72 of which were identified. Most of the compounds were sesquiterpene hydrocarbons, which, depending of the harvest time, corresponded to 43-78% of the total essential oil. The other compounds were distributed as monoterpene hydrocarbons, oxygen-containing sesquiterpenes, n-alkanes, 1-alkenes, and oxygen-containing monoterpenes, these being a minor group. In H. androsaemum in vitro shoots, sesquiterpene hydrocarbons represented >80% of the respective essential oil. Differences in the essential oil composition were found depending on the harvest time and origin, in vivo versus in vitro, of the plant material. The essential oil sampled in November was characterized by the highest levels of sesquiterpene hydrocarbons and a high number of n-alkanes and 1-alkenes, from C(18) to C(28), whereas that sampled in June of the following year showed the highest levels of n-nonane and 1-octene as well as monoterpene hydrocarbons, the second most representative group.     

Dissolved and Particulate Heavy Metals in the Salado River (Santa FE, Argentina)

The objective of this work is to analyze Fe, Mn, Cr, Cd, Cu, Pb, and Zn distributions in the water column in terms of total, dissolved, and particulate concentrations in the Salado River (Santa Fe – Argentina); their relationship with total, dissolved and suspended solids; and the impact of two pollution sources on the watercourse: a stream that collects domestic and industrial wastewater discharges of the region and a direct discharge that releases urban and industrial effluents to the river. Water samples obtained from 5 surveys were analyzed. The Salado River transported a load of heavy metals that ranged from 700 g/s to 2200 g/s of Fe, 20 g/s to 60 g/s of Mn and 1 g/s to 3 g/s of Cr. Results show that most metals were found in particulate form, that the metal input from the direct discharge may be significant at low water levels, whereas a lesser impact was produced by the stream, and that both pollution sources were negligible at high water levels.     

Chemical characterization of the aroma of Grenache rosé wines: aroma extract dilution analysis,quantitative determination,and sensory reconstitution studies

The aroma of a Grenache rosé wine from Calatayud (Zaragoza, Spain) has been elucidated following a strategy consisting of an aroma extract dilution analysis (AEDA), followed by the quantitative analysis of the main odorants and the determination of odor activities values (OAVs) and, finally, by a series of reconstitution and omission tests with synthetic aroma models. Thirty-eight aroma compounds were found in the AEDA study, 35 of which were identified. Twenty-one compounds were at concentrations higher than their corresponding odor thresholds. An aroma model prepared by mixing the 24 compounds with OAV > 0.5 in a synthetic wine showed a high qualitative similarity with the aroma of the rosé wine. The addition of compounds with OAV < 0.5 did not improve the model, whereas the aroma of a model containing only odorants with OAV > 10 was very different from that of the wine. Omission tests revealed that the most important odorant of this Grenache rosé wine was 3-mercapto-1-hexanol, with a deep impact on the wine fruity and citric notes. The synergic action of Furaneol and homofuraneol also had an important impact on wine aroma, particularly in its fruity and caramel notes. The omission of beta-damascenone, which had the second highest OAV, caused only a slight decrease on the intensity of the aroma model. Still weaker was the sensory effect caused by the omission of 10 other compounds, such as fatty acids and their ethyl esters, isoamyl acetate, and higher alcohols.     

Interactive responses to water deficits and crop load in olive (Olea europaea L., cv. Morisca). II: Water use, fruit and oil yield

To understand the relations between water use and yield in response to crop load, two experiments were conducted in olive (cv. Morisca), during six consecutive years (2002-2007) in an experimental orchard located in Badajoz, Southwest Spain. Experiment 1, assessed the responses during the early years of the orchard (2002-2004) using four irrigation treatments that applied fractions of the estimated crop evapotranspiration (ET_c) (125%, 100%, 75% and 0%) and three crop load levels (100%, 50% and 0% of fruit removal, termed Off, Medium and On treatments). Experiment 2 assessed the response of more mature trees (2005-2007) to three irrigation treatments (115%, 100%, and 60% of ET_c) and the natural crop load which were Off, On, and Medium in 2005, 2006 and 2007, respectively. Yield was reduced by water deficits and so did the estimated tree transpiration which was linearly related to yield (y = 1.2302x − 21.15, R² = 0.8864), showing the high sensitivity of cultivar Morisca to water deficits. The relations between fruit number and fruit weight showed that high crop loads had lower fruit weights and oil yield, a decrease that was more pronounced as water deficits increased. The yield response to water supply in the control and excess treatments, and the observations on the water relations of these two treatments suggest that the calculations made using the FAO method (Doorenbos and Pruit, 1974) with the crop coefficient proposed by Pastor et al. (1998) and the reduction coefficient (Fereres et al., 1982) to apply 100% of ET_c in the control treatment, underestimated the ET_c of the orchard. The results indicate that, although the absence of fruits lead to reduced water use as compared to situations of medium and high crop loads, canopy size was much more determinant of orchard water requirements than crop load.     

Monitoring of blood vessels and tissues by a population of monocytes with patrolling behavior

The cellular immune response to tissue damage and infection requires the recruitment of blood leukocytes. This process is mediated through a classical multistep mechanism, which involves transient rolling on the endothelium and recognition of inflammation followed by extravasation. We have shown, by direct examination of blood monocyte functions in vivo, that a subset of monocytes patrols healthy tissues through long-range crawling on the resting endothelium. This patrolling behavior depended on the integrin LFA-1 and the chemokine receptor CX(3)CR1 and was required for rapid tissue invasion at the site of an infection by this "resident" monocyte population, which initiated an early immune response and differentiated into macrophages.     

The global circulation of seasonal influenza A (H3N2) viruses

Antigenic and genetic analysis of the hemagglutinin of approximately 13,000 human influenza A (H3N2) viruses from six continents during 2002-2007 revealed that there was continuous circulation in east and Southeast Asia (E-SE Asia) via a region-wide network of temporally overlapping epidemics and that epidemics in the temperate regions were seeded from this network each year. Seed strains generally first reached Oceania, North America, and Europe, and later South America. This evidence suggests that once A (H3N2) viruses leave E-SE Asia, they are unlikely to contribute to long-term viral evolution. If the trends observed during this period are an accurate representation of overall patterns of spread, then the antigenic characteristics of A (H3N2) viruses outside E-SE Asia may be forecast each year based on surveillance within E-SE Asia, with consequent improvements to vaccine strain selection.     

Wind as a long-distance dispersal vehicle in the Southern Hemisphere

Anisotropic (direction-dependent) long-distance dispersal (LDD) by wind has been invoked to explain the strong floristic affinities shared among landmasses in the Southern Hemisphere. Its contribution has not yet been systematically tested because of the previous lack of global data on winds. We used global winds coverage from the National Aeronautics and Space Administration SeaWinds scatterometer to test whether floristic similarities of Southern Hemisphere moss, liverwort, lichen, and pteridophyte floras conform better with (i) the anisotropic LDD hypothesis, which predicts that connection by "wind highways" increases floristic similarities, or (ii) a direction-independent LDD hypothesis, which predicts that floristic similarities among sites increase with geographic proximity. We found a stronger correlation of floristic similarities with wind connectivity than with geographic proximities, which supports the idea that wind is a dispersal vehicle for many organisms in the Southern Hemisphere.