Search results for "environmental pollutants"
showing 10 items of 170 documents
Deep oxidation of pollutants using gold deposited on a high surface area cobalt oxide prepared by a nanocasting route.
2011
Gold deposited on a cobalt oxide with high surface area (138 m2 g−1), obtained through a nanocasting route using a siliceous KIT-6 mesoporous material as a hard template, has demonstrated high activity for the total oxidation of propane and toluene, and ambient temperature CO oxidation. The addition of gold promotes the activity when compared to a gold-free Co3O4 catalyst prepared using the same nanocasting technique. The enhanced catalytic activity when gold is present has been explained for the deep oxidation of propane and toluene in terms of the improved reducibility of cobalt oxide when gold is added, rather than to the intrinsic activity of metallic gold particles. The improved behavi…
A survey of photocatalytic materials for environmental remediation
2012
Abstract Heterogeneous photocatalysis is an advanced oxidation process which has been the subject of a huge amount of studies related to air cleaning and water purification. All these processes have been carried out mainly by using TiO 2 -based materials as the photocatalysts and ca. 75% of the articles published in the last 3 years is related to them. This review illustrates the efforts in the search of alternative photocatalysts that are not based on TiO 2 , with some exceptions concerning particularly innovative modifications as nanoassembled TiO 2 or TiO 2 composites with active carbon, graphite and fullerene. Papers reporting preparation, characterization and testing of binary, ternary…
Degradation half-life times of PCDDs, PCDFs and PCBs for environmental fate modeling.
2000
Literature search of the knowledge on the degradation of persistent organic pollutants (POPs) in environmental compartments air, water, soil and sediment was done in purpose to find properties of POPs of interest for modeling. One degradation process, hydrolysis (chemical degradation), was omitted as negligibly slow for POPs studied. The other two, photolysis and biodegradation processes, were considered separately in purpose to develop estimation procedures. The estimates can be given as pseudo first-order rate constants kP for photolysis and kB for biodegradation. For each compartment, an overall degradation rate is k(tot) = kP + kB and lifetime t(1/2) = ln 2/k(tot). The latter values, li…
A parsimonious dynamic model for river water quality assessment
2010
Water quality modelling is of crucial importance for the assessment of physical, chemical, and biological changes in water bodies. Mathematical approaches to water modelling have become more prevalent over recent years. Different model types ranging from detailed physical models to simplified conceptual models are available. Actually, a possible middle ground between detailed and simplified models may be parsimonious models that represent the simplest approach that fits the application. The appropriate modelling approach depends on the research goal as well as on data available for correct model application. When there is inadequate data, it is mandatory to focus on a simple river water qua…
Emerging technologies for enhanced removal of residual antibiotics from source-separated urine and wastewaters: A review.
2022
Antibiotic residues are of significant concern in the ecosystem because of their capacity to mediate antibiotic resistance development among environmental microbes. This paper reviews recent technologies for the abatement of antibiotics from human urine and wastewaters. Antibiotics are widely distributed in the aquatic environment as a result of the discharge of municipal sewage. Their existence is a cause for worry due to the potential ecological impact (for instance, antibiotic resistance) on bacteria in the background. Numerous contaminants that enter wastewater treatment facilities and the aquatic environment, as a result, go undetected. Sludge can act as a medium for some chemicals to …
Target analysis and retrospective screening of veterinary drugs, ergot alkaloids, plant toxins and other undesirable substances in feed using liquid …
2015
A comprehensive strategy combining a quantitative method for 77 banned veterinary drugs, mycotoxins, ergot alkaloids and plant toxins, and a post-target screening for 425 substances including pesticides and environmental contaminants in feed were developed using a QuEChERS-based extraction and an ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS). The quantitative method was validated after previous statistical optimisation of the main parameters governing ionisation, and presented recoveries ranging, in general, from 80 to 120%, with a precision in terms of Relative Standard Deviation (RSD) lower than 20%. The full-scan accurate mass data…
Perfluorinated Compounds in Food: A Global Perspective
2011
Perfluorinated compounds (PFCs) are resistant to breakdown and are turning up in unexpected places around the world, becoming emerging food contaminants. Although these chemicals have been used in countless products since the 1950s, they have been subject to little control until now. There is still an insufficient knowledge of their sources, occurrence, and hazards for food safety decision making. This article provides a comprehensive review of the food contamination levels and dietary intake risks posed by PFCs, as well as the specific methods developed for their determination. It is based on the evaluation of the published literature between 2004 and the beginning of 2010, with special em…
Monitoring of persistent organic pollutants in the polar regions: knowledge gaps & gluts through evidence mapping
2017
Persistent organic pollutants (POPs) are widespread compounds that accumulating in polar regions canalise through trophic webs. Although several dozens of studies have been carried out in the last decades, the information is generally scattered across a large number of literature sources. This does not allow an efficient synthesis and constraints our understanding on how address future monitoring plans and environmental conservation strategies on the Polar Regions with respect to POPs. Thus, here, we present the outcome of a systematic map (SM) to scope, screen and chart evidences from literature dealing with POPs in Polar regions. The SMs strive to produce rigorous guidelines and have rece…
Long-Lasting Genomic Instability Following Arsenite Exposure inMammalian Cells: The Role of Reactive Oxygen Species
2011
Previously, we reported that the progeny of mammalian cells, which has been exposed to sodium arsenite for two cell cycles, exhibited chromosomal instability and concurrent DNA hypomethylation, when they were subsequently investigated after two months of subculturing (about 120 cell generations) in arsenite-free medium. In this work, we continued our investigations of the long-lasting arsenite-induced genomic instability by analyzing additional endpoints at several time points during the cell expanded growth. In addition to the progressive increase of aneuploid cells, we also noted micronucleated and multinucleated cells that continued to accumulate up to the 50th cell generation, as well a…
Ecological risks of an old wood impregnation mill: application of the triad approach.
2010
Although many studies deal with the distribution and mobility of chromated copper arsenate (CCA) metals in soil, the ecotoxicity of CCA-contaminated soils is rarely studied. The Triad approach was applied to determine the ecological risks posed by a CCA mixture at a decommissioned wood impregnation mill in southern Finland. A combination of (1) chemical analyses; (2) toxicity tests with plants (aquatic: Lemna minor; terrestrial: Lactuca sativa), earthworms (Lumbricus rubellus), and enchytraeids (Enchytraeus albidus) conducted on contaminated soils, their aqueous extracts, and well water collected from the site; and (3) determination of the abundance of enchytraeids and nematodes and the bio…