1,721,119 research outputs found
Management and Control of Wastewater: An Ecotoxicological Approach
Full text linkWastewater treatment represents a continuous challenge for engineers, environmental scientists and regulators. At the beginning it was the biological load to be reduced as much as possible to prevent infections and eutrophication phenomena. Afterwards, besides domestic discharges, industrial wastewater required specific technologies and treatment facilities to allow the removal of targeted pollutants. Today, an increasing number of new contaminants are rising up such as pharmaceuticals, personal care products and nanomaterials just to cite the most recent categories. The current goal in wastewater management is to move towards the (near-) zero approach or, ideally, the zero-discharge requiring to recover and reuse treated wastewater as much as possible. About that, ecotoxicological tools may offer a great support in the defining the rate of contamination removal during the treatment processes and allow further assessment about effluent second life. An overview of ecotoxicological approaches to assess wastewater environmental impacts to saltwater is presented and discussed considering toxicity tests as essential guidelines. © 2013 Nova Science Publishers, Inc
Phytotoxicity of "green" stabilised micro-iron used for groundwater remediation
Full text linkTreatment with granular, micro- (mFe), and nano-sized (nFe) iron showed to remove several inorganic and organic pollutants. Recently, there has been a turnaround from nFe to mFe: mFe is cheaper than nFe (i.e. 10 €/kg for mFe compared to 100 €/kg) forming less agglomerates. We reported about the potential environmental impacts of mFe considering phytotoxicity effects on four types of iron powders: A (? 600 μm particle size (ps)), B and C (? 250 μm ps) and D (? 50 μm ps). Three macrophytes (Lepidium sativum, Sinapis alba and Sorghum saccharatum) were investigated (OECD, 2006) (seed germination, seedling elongation, germination index and biomass inhibition) exposing organisms to 20 g/L of each mFe stabilised in 2 g/L of Guar gum (GG) in deionized water (GGmFe), spiked with Cd (CdCl2) (1-100 mg/L). Considering real concentrations, preliminary results indicated: i) no adverse effects on L. sativum and S. saccharatrum versus all GGmFe; S. alba showed toxicity versus C and D GGmFe; ii) biostimulation was observed in S. saccharatum versus all GGmFe and L. sativum only versus C GGmFe; iv) mFe seemed to reduce Cd effects in all sample, but with a different efficiency: C > D > A = B; v) the presence of GG seemed to increase bioavailability of Cd
Optimization-based methodology for improving energy efficiency in wastewater treatment plants.
No full textPhytotoxicity of vancomycin: seed germination and root elongation in some crops
No full textDuring last decades, the production and consumption of antibiotics have increased rapidly worldwide. This overuse has been highlighted as one of the biggest emerging threats to human health and ecosystems, due to the undesirable effects related to the antibiotics released into the environment. Most research focused on antibiotic resistance spread, whereas the toxicity to plants remained a quite unexplored field. Agricultural systems are recognized as a potentially significant source of antibiotics to the aquatic environment due to runoff and leaching after biosolid application from wastewater treatment plants, manure from livestock operations, or excretion from free-ranging livestock, but their
effects on crops have not been well documented yet. The present study aimed at assessing the phytotoxic effects of a glycopeptide antibiotic (vancomycin) on seed germination of four different crops (Solanum lycopersicum cv. Crovarese, Solanum lycopersicum cv. San Marzano, Eruca sativa, Diplotaxis tenuifolia) during a short-term exposure (7 d). Crops were exposed to a range of concentrations (0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 7.5, 10, 15, 22 mg/L) of vancomycin. Root and shoot emergence and final length, root elongation rate and total biomass were used as endpoints. Data were analysed by multivariate exploration with a Generalised Canonical Discriminant Analysis -
modelling of parameter-dose relationships via Generalised Additive Models. Results showed that vancomycin can significantly affect the germination of all the analysed cultivars, with the only exception of S. lycopersicum cv. San Marzano
Organotin compounds in marine sediment: Detection and concerns
Full text linkThe determination of organotin compounds (OTCs) in environmental matrices has been subject to great scientific attention during last years, as the accuracy and sensitivity of analytical methods need to be improved in order to be able to detect the compounds of interest in a complex matrix such as sediment. The European Union Water Framework Directive (2013/39/EU) sets very restrictive environmental quality standards for 45 priority substances and other pollutants, including OTCs. Therefore, it is necessary to develop analytical methods in compliance with the environmental quality standard (EQSs) proposed to protect the aquatic environment and human beings. So far various analytical procedures have been used, including gas chromatographic analyses. Most of these methods comprise different steps such as extraction, derivatisation, clean up and the use of several sophisticated instrumentations, as well. Among them the conversion of tributyltin into Sn to allow its determination by Atomic Absorption Spectrometry or Anodic Stripping Voltammetry (AVS) has also been attempted. A great number of studies have been performed on OTCs analysis in marine sediment. However, the only review available in literature discussing the upgrades of analytical methods is dated back to 1997. We reviewed the analytical procedures and discussed them comparatively in order to identify the current state-of-the-art in OTCs detection. Finally, environmental concerns about OTCs were discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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