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Dynamics of Atmospheric Aerosol Number Size Distributions in the Eastern Mediterranean During the “SUB-AERO” Project
2011
Ždímal, Vladimir | Smolík, Jiri | Eleftheriadis, Kostas | Wagner, Zdeněk | Housiadas, Christos | Mihalopoulos, Nikos | Mikuška, Pavel | Večeřa, Zbynek | Kopanakis, Ilias | Lazaridis, Mihalis
Measurements of number size distributions of submicron aerosols have been performed at the Eastern part of Mediterranean as part of an extensive measurement campaign to study photo-oxidants and aerosols (SUB-AERO Project). The measurements were made at the Finokalia station on the island of Crete (Greece) and onboard the research vessel “Aegaeon”. Two campaigns were performed during July 2000 and January 2001 using two scanning mobility particle sizers. The particle distributions measured in the range between 7.8 < d p < 327 nm during the summer measurements and between 7.5 < d p < 316 nm during the winter measurements, where d p is the mobility particle diameter. The concentration of ultrafine particles (7.5 < d p < 30 nm) was higher during the winter period and varied mainly between 5 × 10¹ and 2 × 10³ cm⁻³ with concentration peak values for this mode exceeding 1 × 10⁴ cm⁻³. During the summer campaign, an average number concentration of 1 × 10² cm⁻³ at Finokalia and about 5 × 10¹ cm⁻³ aboard the “Aegaeon” vessel was measured. An average concentration of 1 × 10³ cm⁻³ was measured for the particles in the size range between 30 and 100 nm, whereas in the size range 100-300 nm, the measured concentration ranged between 1 × 10² and 5 × 10³ cm⁻³. Diurnal patterns in number concentrations were observed in connection with the transport of air masses and local sources. During the winter period, three nucleation events were observed in connection with the appearance of a particle mode at 20 nm.
Mostrar más [+] Menos [-]Microbiological Quality and Antibiotic Resistance Analysis of a Brazilian Water Supply Source
2011
da Silva, Trajano Felipe Barrabas Xavier | Ramos, Débora Toledo | Dziedzic, Maurício | de Oliveira, Cíntia Mara Ribas | de Vasconcelos, Eliane Carvalho
Water samples of the Passaúna River, Curitiba/Paraná (Brazil), were analyzed to determine total and thermotolerant coliform counts and Escherichia coli in order to provide information on human impacts on the water supply. Samples were collected and analyzed monthly, from March 2006 to February 2007, at five different locations along the river, and the multiple tube method was used to obtain total and thermotolerant coliform counts. The results varied from 130 MPN/100 mL to 1.6 × 106 MPN/100 mL for total coliforms, while for thermotolerant coliforms the variation was between 40 MPN/100 mL and 5 × 105 MPN/100 mL. The E. coli strains isolated from the samples were tested with 13 different antibiotics to determine their antibiotic resistance. The isolated strains were constantly sensitive to seven of the 13 antibiotics tested, and resistant to at least one of the other antibiotics. The results indicated that two factors could influence the increased contamination on this river, viz., seasonality parameters and domestic wastewater discharges. The determination of antibiotic resistance indices aimed to provide information on the anthropogenic influence. Only one of the locations investigated was considered critical due to the anthropogenic influence, with significant impacts from irregular domestic wastewater discharges.
Mostrar más [+] Menos [-]Cupric Reductase Activity in Copper-Resistant Amycolatopsis tucumanensis
2011
Dávila Costa, José Sebastián | Albarracín, Virginia Helena | Abate, Carlos Mauricio
Amycolatopsis tucumanensis, a recently recognized novel species showed remarkable copper resistance as well as efficient Specific Cupric Reductase Activity (SRACu) in both, copper adapted and non-adapted cells, under different temperatures of incubation. Its copper resistance strength was highlighted against other metal-resistant actinobacteria (Streptomyces sp. AB5A) and sensitive strains (Amycolatopsis eurytherma and Streptomyces coelicolor). Pre-adapted cells of A. tucumanensis displayed values of SRACu, on average, 65% higher than those obtained from non-adapted cells. In addition, preadaptation of A. tucumanensis improved the rate of Cu(II) reduction which was approximately, two-, seven- and ninefold higher than pre-adapted cells from Streptomyces sp. AB5A, A. eurytherma and S. coelicolor, respectively. A. tucumanensis showed the highest levels of SRACu at all temperatures and also the highest copper resistance profile, suggesting that these two abilities may be in close relationship. This ostensible versatility, related to the temperature, of adapted cells from A. tucumanensis might support the application of this strain under different bioremediation conditions. To our knowledge this is the first time that cupric reductase activity was demonstrated within the genus Amycolatopsis.
Mostrar más [+] Menos [-]Differential Sex, Morphotype and Tissue Accumulation of Mercury in the Crab Carcinus maenas
2011
Costa, Sónia | Viegas, Ivan | Pereira, Eduarda | Duarte, Armando C. | Palmeira, Carlos M. | Pardal, Miguel A.
Carcinus maenas is an invasive species of recognised economical and ecological importance in which mercury accumulation could be a pathway for bioamplification through food webs. Little information is available about differential accumulation between crab sexes and morphotypes. Taking this in mind, a set of different industrial discharge scenarios were investigated in 96-h laboratory experiments for assessing the accumulation of inorganic mercury from contaminated seawater into the tissues of C. maenas. Three groups of crabs (green males, green and red females) where exposed to 5, 50 and 250 μg Hg L−1. Differences among sexes, morphotypes and tissues were detected, depending on the mercury concentration. The muscle did not show differential accumulation between sexes or morphotypes. For mercury-exposed crabs, the contaminant was accumulated preferably in the gills (more than 75%) while, in control experiments, it was in the internal organs, muscle and hepatopancreas, and gills corresponded to less than 31% of the total mercury quantified. The different tissue contamination seems dependent on the major pathway of exposure, diet or water. Mercury accumulation by the crab was a rapid process and could represent a risk for the environment only after 96 h. In a scenario of a discharge point of 250 μg L−1, all tissues of crabs exposed would attain a very close, or even exceed the threshold concentration value for human consumption (0.5 mg kg−1).
Mostrar más [+] Menos [-]Enhanced Tolerance to Mercury in a Streptomycin-Resistant Strain of Euglena gracilis
2011
Devars, Silvia | Rodríguez-Zavala, José Salud | Moreno Sánchez, Rafael
Toxicity of Hg2+ was determined in two strains of Euglena gracilis var. bacillaris: the wild-type (B) and a streptomycin-resistant strain (Smr). Cells were cultured under 12-h dark/12-h light regime or under continuous darkness. In the dark/light cultures, cellular growth was severely diminished in the B strain by Hg2+, whereas only a slight decrease was attained in the Smr strain; Hg2+ also affected the photosynthetic and respiratory activities of the B strain, but not those of Smr strain. Under continuous darkness, cellular growth of both strains was lower than under dark/light cycles, but it was inhibited by Hg2+ to a much lesser extent. Cell culture by 5 days under continuous dark or by 8 days of dark/light cycles resulted in a higher intracellular content of mercury in B strain than in Smr strain. In contrast, in both culture conditions, the fraction of mercury removed from medium by B strain was lower than that attained by Smr strain, whereas the ability to bio-transform (reduce) Hg2+ was two times higher in the mutant strain. The results suggested that Smr strain cells acquired an ability to remove Hg2+ from the medium, which was not associated to accumulation and which conferred protection against mercury.
Mostrar más [+] Menos [-]Wet and Dry Deposition Fluxes of Polychlorinated Biphenyls (PCBs) in an Urban Area of Turkey
2011
Günindi, Manolya | Tasdemir, Yücel
Atmospheric polychlorinated bihenyls (PCBs) deposit by dry and wet deposition mechanisms, and therefore they constitute a significant polluting source for lands and surface waters. Various samplers have been used to determine the PCB pollution level resulting from deposition. In the presented study, a modified wet deposition sampler (WDS) was used for sampling both wet and dry deposition samples with the same instrument by which wet deposition reservoir of the WDS is opened and dry deposition reservoir is closed when rain starts. Wet and dry deposition samples were collected between June 2008 and June 2009. In the samples taken from BUTAL which is known as an urban area with heavy traffic, âPCB dry deposition fluxes were determined as 18â±â10 ng/m2â−day, and wet deposition fluxes for dissolved and particle phase were measured as 480â±â1,185 and 475â±â1,000 ng/m2â−day, respectively. The dissolved and particle-phase PCB concentrations in rain were 10â±â13 and 13â±â14 ng/l, respectively. The contribution of wet deposition to total PCB deposition was determined as 52%. PCB concentrations in the ambient air were measured to be 370â±â200 and 20â±â20 pg/m3 for gas and particle phases, respectively. Washout ratio was determined by proportioning rain concentration to concentration in air. The washout ratios of the samples were between 1,675–311,800 and 12,775–2,511,120 for dissolved and particulate phases, respectively.
Mostrar más [+] Menos [-]Stability of Fe- and Mn-(oxyhydr)oxides in Common Soil Dispersion Solutions
2011
Manh, Phung N. | Ali Khan, Moonis | Jeon, Byong-Hun | Kim, Jae Gon | Lee, Giehyeon
Soil dispersion is a prerequisite process for the separation of metal oxides from bulk soil when magnetic separation is employed to enhance the efficiency for soil treatment. This study examined the stability of goethite, hematite, birnessite, and manganite in common dispersion solutions. The stability of pH in the oxide suspension decreased in the order carbonate (50Â mM Na2CO3) > pyrophosphate (50Â mM Na4P2O7) > simple alkaline (1Â mM NaOH) solutions regardless of the oxides. Dissolution of the four oxides was negligible in the carbonate and the simple alkaline solutions. In the pyrophosphate solutions, however, the oxides were subject to ligand-promoted dissolution by pyrophosphate ion. The extent of dissolution was highest for goethite followed by manganite, hematite, and birnessite. Dissolved Fe and Mn concentrations reached 68.3 and 4.1Â μM for goethite and manganite suspensions, respectively, in 21Â days with 5Â mM pyrophosphate. Higher pyrophosphate concentrations (up to 150Â mM) did not substantially affect the extent of ligand-promoted dissolution due to the limited surface sites of the oxides. The results of this study suggest that the carbonate solution would be more desirable than the simple alkaline or the pyrophosphate solution for soil dispersion in the presence of common Fe or Mn oxides.
Mostrar más [+] Menos [-]Polybrominated Diphenyl Ethers Mobility in Biosolids-Amended Soils Using Leaching Column Tests
2011
Gorgy, Tamer | Li, Loretta Y. | Grace, John R. | Ikonomou, Michael G.
Leaching column tests were conducted to determine the mobility of polybrominated diphenyl ethers (PBDEs) in biosolids-amended soils. Deionized water was introduced from the bottom of a glass leaching column containing a 14-mm layer of biosolids-amended soils (210 g) under 42 mm of agricultural soil (600 g). After 4 weeks of leaching, 3.75 L of deionized water had passed through the 210-g biosolids–soil layer and 600 g soil, corresponding to 34 volumes of the leachate per volume of solid. The agricultural soil was divided into three 14-mm layers to determine the PBDE distribution along the flow path of the infiltrating water. PBDEs were found to leach from the biosolids-amended soils layer and migrate through the soil. The predominant congeners BDE47, 85, 99, 100, 153, 154, 183, and 209 decreased to 3–98% of their initial concentrations in the biosolids-amended soil, whereas the total concentration of these eight congeners decreased by 38%. PBDE concentrations in the first 14-mm soil layer increased from not detected (nd) to up to 234 × 103 pg/g dry weight basis (dw). Concentrations in the second and third soil layers increased from nd to 20 and 25 pg/g dw. PBDE in the leachate increased from nd to 310 × 103 pg/L. Mobilization of PBDEs is likely associated with dissolved organic matter and colloids in the infiltrating water.
Mostrar más [+] Menos [-]Evaluation of First Flush for Indicator Bacteria and Total Suspended Solids in Urban Stormwater Runoff
2011
Hathaway, Jon M. | Hunt, W. F. (William Frederick)
An urban watershed in Raleigh, NC, was evaluated for Escherichia coli (E. coli), fecal coliform, enterococci, and total suspended solids (TSS) over 20 storm events. Sampling procedures allowed collection of multiple discrete samples per event, resulting in a relatively detailed description of microbe and TSS export for each storm. Data were evaluated to determine if a first flush effect was present for indicator bacteria and TSS in stormwater runoff. Analyses suggested there was a significant first flush effect for fecal coliform and TSS, although the first flush effect for fecal coliform was relatively weak. For E. coli and enterococci, no significant first flush effect was noted. Overall, the first flush effect was not always present for indicator bacteria and, if present, tended to be weak. The first flush effect for TSS was substantially stronger than that of any indicator bacteria. Further analysis showed poor correlation between first flush strength and antecedent climate variables, storm characteristics, and flow characteristics. However, seasonal differences for first flush strength were noted. Specifically, winter storms showed a stronger first flush effect for all indicator bacteria. The results of this study indicate that stormwater runoff presents a potential public health hazard due to elevated indicator bacteria levels for all portions of the storm event. Further, stormwater management practices cannot be expected to treat proportionally more indicator bacteria when sized for the water quality event. Instead, removal will simply be a function of a management practice’s volume capture and microbe sequestration efficiency.
Mostrar más [+] Menos [-]Metal Uptake by Spontaneous Vegetation in Acidic Mine Tailings from a Semiarid Area in South Spain: Implications for Revegetation and Land Management
2011
Conesa, Héctor M. | Faz, Ãngel
Tailings are frequently a source of pollution in mining areas due to the spread of metals from their bare surfaces via wind or runoff water. Phytostabilization is an interesting and low-cost option to decrease environmental risks in these sites. In this study, an acidic mine tailing (pH 3–4) located in a semiarid area in Southeast Spain and the spontaneous vegetation which grow on were investigated. Soil samples were taken to characterize metal contamination, and three plant species, Lygeum spartum, Piptatherum miliaceum, and Helichrysum decumbens, were sampled in order to determine plant uptake of metals. The rhizosphere pH of H. decumbens was measured to be 6.7, which was significantly higher than the bulk soil (pH 3). The electrical conductivity values were around 2–5 dS m−1. Total metal concentrations in soil were high (9,800 mg kg−1 for Pb and 7,200 mg kg−1 for Zn). DTPA-extractable Zn and Pb were 16% and 19% of the total amount, respectively. The three selected plant species accumulated around 2–5 mg kg−1 Cu in both shoots and roots. Zn concentration was 100 mg kg−1 in P. miliaceum roots. DTPA-extractable Zn was positively correlated with Zn plant uptake. These plant species demonstrated to grow well in acid tailings taking up only low concentrations of metals and therefore are good candidates to perform further phytostabilization works.
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