Detection of airborne Legionella while showering using liquid impingement and fluorescent in situ hybridization (FISH)

Aerosols of water contaminated with Legionella bacteria constitute the only mode of exposure for humans. However, the prevention strategy against this pathogenic bacteria risk is managed through the survey of water contamination. No relationship linked the Legionella bacteria water concentration and their airborne abundance. Therefore, new approaches in the field of the metrological aspects of Legionella bioaerosols are required. This study was aimed at testing the main principles for bioaerosol collection (solid impaction, liquid impingement and filtration) and the in situ hybridization (FISH) method, both in laboratory and field assays, with the intention of applying such methodologies for airborne Legionella bacteria detection while showering. An aerosolization chamber was developed to generate controlled and reproducible L. pneumophila aerosols. This tool allowed the identification of the liquid impingement method as the most appropriate one for collecting airborne Legionella bacteria. The culturable fraction of airborne L. pneumophila recovered with the liquid impingement principle was 4 and 700 times higher compared to the impaction and filtration techniques, respectively. Moreover, the concentrations of airborne L. pneumophila in the impinger fluid were on average 7.0 x 10(5) FISH-cells m(-3) air with the fluorescent in situ hybridization (FISH) method versus 9.0 x 10(4) CFU m(-3) air with the culture method. These results, recorded under well-controlled conditions, were confirmed during the field experiments performed on aerosols generated by hot water showers in health institutions. This new approach may provide a more accurate characterization of aerobiocontamination by Legionella bacteria.     

Chronic risk assessment of exposure to volatile organic compounds in the atmosphere near the largest Mediterranean industrial site

This study focuses on characterising the risk of exposure to volatile organic compounds (VOCs) by means of inhalation in people living in the vicinity of the largest chemical production site in the Mediterranean area. Eighty-six VOCs were initially selected for this study based on their adverse environmental and health effects. The monitoring campaign was conducted for 276 days in three different locations around the chemical site. The analytical method used for the characterisation was based on European standard method EN-14662-2, which consists of the active sampling of air for 24 h in charcoal tubes, followed by extraction with carbon disulphide and GC-MS analysis. Forty-four VOCs with toxicological data available concerning their carcinogenic and non-carcinogenic health effects were quantified during the monitoring campaign. None of the quantified VOCs showed average concentrations exceeding their chronic reference concentrations and, therefore, no non-carcinogenic health effects are expected as a result of this exposure. However, the global average cancer risk due to VOC exposure in the area (3.3 × 10^− 4) was found to be above the values recommended by the WHO and USEPA.The influence of the analytical method was also evaluated by comparing cancer risk estimates using a thermal desorption (TD) method based on method EN-14662-1. The results of the 24-h samples for the solvent extraction method were compared with the average of 12 daily samples of 2-h for the TD method for 24 sampling days. Although the global estimated lifetime cancer risk was statistically comparable for both methods, some differences were found in individual VOC risks.To our knowledge, this is the first study that estimates the carcinogenic and non-carcinogenic risks posed by the inhalation of VOCs in people living near a chemical site of this size, and compares the estimated cancer risk obtained using two different standard analytical methods.     

Electrochemical combustion of herbicide mecoprop in aqueous medium using a flow reactor with a boron-doped diamond anode

The anodic oxidation of 1.8l of solutions with mecoprop (2-(4-chloro-2-methylphenoxy)-propionic acid or MCPP) up to 0.64 g l(-1) in Na2SO4 as background electrolyte within the pH range 2.0-12.0 has been studied using a flow plant containing a one-compartment filter-press electrolytic reactor with a boron-doped diamond (BDD) anode and a stainless steel cathode, both of 20-cm2 area. Electrolyses carried out in batch under steady conditions and operating at constant current density between 50 and 150 mA cm(-2) always yield complete mineralization due to the great concentration of hydroxyl radical generated at the BDD anode. The degradation rate is practically independent of pH and Na2SO4 concentration, but it becomes faster with increasing MCPP concentration, current density, temperature and liquid flow rate. The effect of these parameters on current efficiency and energy cost has also been investigated. Generated weak oxidants such as H2O2 and peroxodisulfate ion have little influence on the mineralization process. The kinetics for the herbicide decay follows a pseudo first-order reaction with a higher rate constant when current density increases. Aromatic products such as 4-chloro-o-cresol, 2-methylhydroquinone and 2-methyl-p-benzoquinone, and generated carboxylic acids such as maleic, fumaric, lactic, pyruvic, tartronic, acetic and oxalic, have been identified as intermediates by chromatographic techniques. The initial chlorine is completely released in the form of chloride ion, which is slowly oxidized to Cl2 at the BDD anode. A reaction pathway for MCPP mineralization involving all products detected is proposed.     

Sequential electrochemical treatment of dairy wastewater using aluminum and DSA-type anodes

Dairy wastewater is characterized by a high content of hardly biodegradable dissolved, colloidal, and suspended organic matter. This work firstly investigates the performance of two individual electrochemical treatments, namely electrocoagulation (EC) and electro-oxidation (EO), in order to finally assess the mineralization ability of a sequential EC/EO process. EC with an Al anode was employed as a primary pretreatment for the conditioning of 800 mL of wastewater. A complete reduction of turbidity, as well as 90 and 81 % of chemical oxygen demand (COD) and total organic carbon (TOC) removal, respectively, were achieved after 120 min of EC at 9.09 mA cm^?2. For EO, two kinds of dimensionally stable anodes (DSA) electrodes (Ti/IrO₂-Ta₂O₅ and Ti/IrO₂-SnO₂–Sb₂O₅) were prepared by the Pechini method, obtaining homogeneous coatings with uniform composition and high roughness. The ^·OH formed at the DSA surface from H₂O oxidation were not detected by electron spin resonance. However, their indirect determination by means of H₂O₂ measurements revealed that Ti/IrO₂-SnO₂–Sb₂O₅ is able to produce partially physisorbed radicals. Since the characterization of the wastewater revealed the presence of indole derivatives, preliminary bulk electrolyses were done in ultrapure water containing 1 mM indole in sulfate and/or chloride media. The performance of EO with the Ti/IrO₂-Ta₂O₅ anode was evaluated from the TOC removal and the UV/Vis absorbance decay. The mineralization was very poor in 0.05 M Na₂SO₄, whereas it increased considerably at a greater Cl^? content, meaning that the oxidation mediated by electrogenerated species such as Cl₂, HClO, and/or ClO^? competes and even predominates over the ^·OH-mediated oxidation. The EO treatment of EC-pretreated dairy wastewater allowed obtaining a global 98 % TOC removal, decreasing from 1,062 to <30 mg L^?1.     

Ovarian maturation of the multi-spawning spider crab <Emphasis Type="Italic">Maja brachydactyla</Emphasis> (Decapoda: Majidae) with special reference to yolk formation

In the study of the reproductive biology of the spider crab Maja brachydactyla, the morphology of the female reproductive system and yolk formation have long been overlooked. Females spawn two or three times during their annual reproductive cycle in northern Spain (Galicia). The ovaries consist of two lobes. The right and left lobes are connected by a small cross-lobe at the level of the heart and merge at the posterior edge. Before merging, the ovaries descend to the ventral part of the body, joining the spermathecae in the vagina, which opens through a chitin tube to the gonopore, located in the sternite, at the level of the third walking leg. No morphological changes have been observed between either the different parts of the ovaries or the different annual spawning periods. At the start of vitellogenesis, the oocyte of M. brachydactyla is characterized by a large number of vesicles in the cytoplasm. These vesicles are surrounded by a unit membrane whose size increases as the oocyte matures and contain fine granular material including a variable number of ovoid, electron-dense granules. The vesicles are of diverse origin, although most of them develop directly from the mitochondria and the Golgi complex (endogenous phase of vitellogenesis). In a subsequent phase, a series of substances (principally lipoproteins) are incorporated into the ooplasma by means of micropinocytosis. These substances are also involved in yolk formation (exogenous phase of vitellogenesis). During vitellogenesis in M. brachydactyla, mitochondria play the most important role since they are not only the energetic centre of the cellule, but they also act as containers of high-energy reserve substances: the yolk granules.     

Aniline degradation by Electro-Fenton and peroxi-coagulation processes using a flow reactor for wastewater treatment

The degradation of 10-30 l of a 1000 ppm aniline solution in 0.050 M Na2SO4 + H2SO4 at pH 3.0 and 40 degrees C by Electro-Fenton and peroxi-coagulation processes at constant current until 20 A has been studied using a pilot flow reactor in recirculation mode with a filter-press cell containing an anode and an oxygen diffusion cathode, both of 100 cm2 area. H2O2 is produced by the two-electron reduction of O2 at the cathode, being accumulated with a current efficiency between 60% and 80% at the first stages of electrolyses performed with a Ti/Pt anode. In the presence of 1 mM Fe2+, less H2O2 is accumulated, but it is not detected using an Fe anode. The Electro-Fenton process with 1 mM Fe2+ and a Ti/Pt or DSA anode yields an insoluble violet polymer, while the soluble total organic carbon (TOC) is gradually removed, reaching 61% degradation after 2 h at 20 A. In this treatment, pollutants are preferentially oxidized by hydroxyl radicals formed in solution from reaction of Fe2+ with H2O2. The peroxi-coagulation process with an Fe anode has higher degradation power, allowing to remove more than 95% of pollutants at 20 A, since some intermediates coagulate with the Fe(OH)3 precipitate formed. Both advanced electrochemical oxidation processes (AEOPs) show moderate energy costs, which increase with increasing electrolysis time and applied current.     

Estimating zooplankton biomass through image analysis

Zooplankton biomass can be reliably estimated by a non-destructive method based on the statistical relationship between biovolume and the contents of carbon and nitrogen. Integrated zooplankton biovolume and the corresponding organic C and N contents were analysed in paired fresh and fixed (hexamine-buffered formalin) samples. Sample biovolume was estimated through the integration of individual volumes obtained by semi-automatic image analysis on fixed zooplankton samples. The corresponding C and N contents of paired fresh and preserved zooplankton were analysed with a Carlo-Erba C-H-N Analyser. The method allows simultaneous measurement of integrated and individual numbers and biomass (biovolume, C and N) spectrum. It is non-destructive and allows the minimization of errors and variability attributable to differences in the handling processes of samples and to the presence of particles other than zooplankton, like phytoplankton or detritus particulate matter.     

First Serological Study of Hepatitis E Virus Infection in Backyard Pigs from Serbia

Hepatitis E virus (HEV) genotype 3 infections in pigs and humans have been lately reported in Europe. In the present study, the prevalence of anti-HEV IgG antibodies in swine was investigated, for the first time, in Serbia by means of an ELISA based on a recombinant open reading frame 2 protein of HEV genotype 3. A total of 315 serum samples from 3 to 4 months-old healthy backyard pigs, collected in 63 herds from 28 towns and villages of 4 different districts of the Vojvodina province, in the northern part of Serbia, were tested. A 34.6% (109/315) of the sera tested were positive. The prevalence of anti-HEV antibodies varied widely between municipalities (range 16.7–75.0%) and herds (range 0–100%). These data indicate that HEV infection is widespread in Serbian backyard pigs.     

Expression and Immunoreactivities of Hepatitis E Virus Genotype 3 Open Reading Frame-2 (ORF-2) Recombinant Proteins Expressed in Insect Cells

Hepatitis E virus (HEV) is a fecal-orally transmitted virus that is endemic in many geographical areas with poor sanitary conditions and inadequate water supplies. In Europe, a low-endemic area, an increased number of autochthonous sporadic human cases of patients infected with HEV strains of genotype 3, have been reported lately. The relatively high prevalence of HEV genotype 3 infections in European pigs has raised concerns about a potential zoonotic transmission to humans. Determination of HEV seroprevalence in pigs would help to clarify its incidence and possible zoonotic implications. To this purpose, we have expressed and partially characterized swine genotype 3 HEV open reading frame-2 proteins upon infection of Sf21 insect cells with recombinant baculoviruses. The use of the expressed proteins as diagnostic antigens for the detection of antibodies to HEV has been further assayed with human and swine sera.