Reductive remediation methods
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Two parallel pilot experiments were performed at Kurivody (Czech Republic) in order to compare two reductive remedial technologies for chlorinated ethenes - microbial dehalogenation assisted by lactate and chemical dehalogenation with zero-valent iron (nZVI) nanoparticles. The methods were applied at a site contaminated by tetrachlorethylene (PCE) and trichlorethylene (TCE), with total concentrations from 10 to 50 mg/l. Concentrations of chlorinated ethenes, inorganic components of interest, pH and oxidation reduction potential (ORP) were monitored at the site for a period up to 650 days. The method of biological reductive dechlorination supported by lactate showed a considerable removal of PCE and TCE, but temporary accumulation of transient reaction product 1,2-cis-dihloroethene. Reductive dechlorination with nZVI showed a significant reduction in the concentration of chlorinated ethenes without a formation of intermediate products. The development of pH showed only small changes due to the high buffering capacity of the aquifer. Both methods differ in the initial development of ORP, but over the long term showed similar values around 100 mV. Significant differences were observed for chemical oxygen demand, where groundwater after the application of nZVI showed no change in comparison to the application of lactate. The reductive effects of both agents were verified by changes in inorganic compound concentrations.
- MeSH
- chlor izolace a purifikace MeSH
- chlorované uhlovodíky chemie MeSH
- koncentrace vodíkových iontů MeSH
- kyselina mléčná chemie MeSH
- látky znečišťující životní prostředí chemie MeSH
- oxidace-redukce MeSH
- pilotní projekty MeSH
- regenerace a remediace životního prostředí metody MeSH
- železo chemie MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Over the past two decades, the use of nanoscale zero-valent iron (nZVI) has emerged as a standard method of contaminated groundwater remediation. The effectiveness of this method depends on key intrinsic hydrogeological parameters, which can affect both reactivity of the nanoparticles and their migration in the aquifer. In the case of low hydraulic permeability, the migration of nanoparticles is limited, which negatively influences remediation. An application of nZVI reinforced with a DC electric field led to a significant increase in the efficiency of remediation, as demonstrated by long-term monitoring at a former industrial site in Horice (Czech Republic). For the method testing, a 12 × 9 m polygon was defined around well IS4, where the original contamination was predominantly composed of DCE (7300 μg/l), and with a total concentration of chlorinated ethenes of 8880 μg/l. During the first stage of the activities, 49 kg of nZVI was injected and monitored for two years. Subsequently, the electrodes were installed, and for three years, the synergistic action of nZVI within an applied DC field was monitored. Based on 32 monitoring campaigns performed over the six years, the combined method was compared with an application of the only nZVI in technical, environmental and economic terms. Technically, the method requires annual reinstallation of anodes as a result of their oxidative disintegration. Environmentally, the method provides significantly improved chlorinated ethane reduction, remediation of low permeable zones, and extended efficiency. Economically, the method is five times cheaper when compared to the nZVI used alone.
- MeSH
- chemické látky znečišťující vodu analýza chemie MeSH
- ethyleny analýza chemie MeSH
- halogenace MeSH
- kovové nanočástice chemie MeSH
- podzemní voda MeSH
- regenerace a remediace životního prostředí * MeSH
- železo MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
The paper describes a pilot remediation test combining two Cr(VI) geofixation methods - chemical reduction by nanoscale zero-valent iron (nZVI) and subsequent biotic reduction supported by whey. Combination of the methods exploited the advantages of both - a rapid decrease in Cr(VI) concentrations by nZVI, which prevented further spreading of the contamination and facilitated subsequent use of the cheaper biological method. Successive application of whey as an organic substrate to promote biotic reduction of Cr(VI) after application of nZVI resulted in a further and long-term decrease in the Cr(VI) contents in the groundwater. The effect of biotic reduction was observed even in a monitoring well located at a distance of 22 m from the substrate injection wells after 10 months. The results indicated a reciprocal effect of both the phases - nZVI oxidized to Fe(III) during the abiotic phase was microbially reduced back to Fe(II) and acted as a reducing agent for Cr(VI) even when the microbial density was already low due to the consumed substrate. Community analysis with pyrosequencing of the 16S rRNA genes further confirmed partial recycling of nZVI in the form of Fe(II), where the results showed that the Cr(VI) reducing process was mediated mainly by iron-reducing and sulfate-reducing bacteria.
- MeSH
- chemické látky znečišťující vodu chemie MeSH
- chrom chemie MeSH
- fosfolipidy analýza MeSH
- mikrobiologie vody MeSH
- monitorování životního prostředí MeSH
- oxidace-redukce MeSH
- pilotní projekty MeSH
- podzemní voda chemie MeSH
- redukční činidla chemie MeSH
- regenerace a remediace životního prostředí metody MeSH
- RNA ribozomální 16S chemie genetika MeSH
- syrovátka chemie MeSH
- železité sloučeniny chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This study investigates redox transitions associated with the adsorption of Cr(VI) on commonly occurring soil components (silicates, oxides and humic acids) and their synthetic mixtures by coupling the mechanistic surface complexation modeling with spectroscopic and isotopic analyses. The mixtures of soil components were prepared to reflect the composition of the real anthroposol sample, determined by X-ray Powder Diffraction (XRD), total organic carbon (TOC) measurement and extraction methods. The effect of different initial Cr(VI) concentrations (2×10-2, 5×10-4, 10-4, 10-5, and 10-6M), background electrolyte (10-3, 10-2, and 10-1M KNO3), pH values (3-9), and sorbate/sorbent ratios (2g/L - 20g/L) were investigated. Maghemite and ferrihydrite were confirmed to be the main phases controlling Cr(VI) adsorption with increasing Cr(VI) concentration. Humic acids were primarily responsible for Cr(VI) reduction, especially at low pH values. The reduction of Cr(VI) was also proved in case of illite and kaolinite by XAS and isotopic analyses. Illite revealed higher reduction capacity in comparison with kaolinite based on XAS measurements. Chromium isotopic fractionation, resulting from Cr(VI) reduction, was the highest in the case of humic acids, followed by kaolinite and illite. However, a dissolution of intrinsic Cr originally present within kaolinite and illite might affect the final Cr isotopic composition of the supernatants due to its different Cr isotopic signature. In general, the combination of three different approaches was confirmed to offer more comprehensive information about Cr(VI) adsorption and/or reduction in soils. Detailed studies using soil mixtures can help to predict how the soil components affect Cr(VI) behavior in natural soils and possibly could improve the environmental remediation processes.
Lindane (γ-hexachlorocyclohexane) and its isomers (HCH) are some of the most common and most easily detected organochlorine pesticides in the environment. The widespread distribution of lindane is due to its use as an insecticide, accompanied by its persistence and bioaccumulation, whereas HCH were disposed of as waste in unmanaged landfills. Unfortunately, certain HCH (especially the most reactive ones: γ- and α-HCH) are harmful to the central nervous system and to reproductive and endocrine systems, therefore development of suitable remediation methods is needed to remove them from contaminated soil and water. This paper provides a short history of the use of lindane and a description of the properties of HCH, as well as their determination methods. The main focus of the paper, however, is a review of oxidative and reductive treatment methods. Although these methods of HCH remediation are popular, there are no review papers summarising their principles, history, advantages and disadvantages. Furthermore, recent advances in the chemical treatment of HCH are discussed and risks concerning these processes are given.
Electric field assisted remediation using nano iron has shown outstanding results as well as economic benefits during pilot applications (Černíková et al., 2020). This method is based on donating electrons to the zero-valent iron that possess an inherently strong reductive capacity. The reduction of chlorinated hydrocarbons may be characterized by a decrease in contaminants or better still by the evolution of ethene and ethane originating from the reduction of chlorinated ethenes. The evolution of ethene and ethane was observed predominantly in the vicinity of the anode despite reduction processes being expected near the cathode - the electron donor. The reduction near the anode occurred due to dissolved Fe2+ ions, whose presence was suggested by a Pourbaix diagram that combines Eh/pH values to characterize electrochemical stabilities between different species. No products of dechlorination were observed in the area of the cathode due to presence of oxidized Fe in the form of Fe3+ or Fe(OH)4-. The experimental work described in this research provides a deeper view of the processes of electrochemical reductive dechlorination using zero-valent iron and DC. It also showed an increase in the efficiency compared to the method using zero-valent iron only.
Cíl práce: Cílem byla analýza výskytu pertusse v Českých zemích a vyhodnocení okolností, které tento výskyt ovlivňovaly, zejména vyhodnocení vlivu očkování na incidenci onemocnění, na klinickou závažnost onemocnění a na cirkulaci Bordetella pertussis v populaci. Cílem práce byla také analýza příčin nedostatků v diagnostice a hlášení onemocnění a vypracování návrhu na jejich zlepšení. Metodika: Údaje o nemocnosti pertussí byly získány z archivu SZÚ a programů ISPO a EPIDATinformačních systémů Hygienické služby. Údaje o úmrtnosti kromě uvedených zdrojů i z publikací. Definice případu onemocnění byla specifikována v Metodickém pokynu Surveillance pertusse a podle direktivy EC. Laboratorní diagnóza onemocnění byla prováděna kultivačním a sérologickým vyšetřením. Za pozitivní výsledek byl považován nejméně 4 násobný vzestup titru protilátek sér, vyšetřených v jednom pokusu. Výsledky: Onemocnění pertussí patřilo spolu s difterií a spalničkami mezi nejnebezpečnější infekce dětského věku. Nejstarší údaje o úmrtnosti se datují do roku 1890–62/100 000. Ještě v roce 1951 dosahovala 3,6/100 000. Nemocnost dosáhla vrcholu v roce 1955–540/100 000. Očkování proti pertussi zahájené začátkem padesátých let vedlo k rychlému poklesu nemocnosti dětských věkových skupin. Stále se však pravidelně objevovaly ve 2–4letých intervalech roky s vyšším výskytem onemocnění (tzv. epidemické roky). Nejnižších hodnot dosáhla nemocnost až v průběhu 80. let. V následujících letech má však nemocnost stabilně stoupající trend. V roce 2006 došlo dokonce i k úmrtí novorozence na pertussi. Specifická nemocnost podle věku byla v letech 1980–2000 nejvyšší ve věkové skupině dětí mladších 1 roku. Toto zjištění spolu s pravidelně se vyskytujícími roky s vyšší nemocností ve 2–3letých intervalech znamená, že v populaci stále cirkuluje Bordetella pertussis. Zatímco v 80. letech se onemocnění pertussí vyskytovalo téměř výlučně u dětí mladších jednoho roku, v devadesátých se spektrum nemocných rozšiřuje o 1–4leté a postupně další dětské věkové skupiny a od roku 2001 prevaluje věková skupina 10–14letých. Závěr: Vysoká proočkovanost (97 %) pěti dávkami kvalitní celobuněčné očkovací látky české výroby zavedené do praxe v r. 1958 se podílela rozhodujícím způsobem na snížení nemocnosti pertusse z hodnot vyšších než 500/100 000 v polovině padesátých let na hodnoty nižší než 0,5/100 000 v osmdesátých letech. Nicméně ani tato strategie nevedla k eliminaci původce pertusse v populaci. Je zřejmé, že současné očkovací schéma za použití současných očkovacích látek není schopno epidemiologickou situaci vyřešit. Vzhledem k tomu, že účinnost současných acelulárních očkovacích látek proti pertussi je v nejlepším případě stejná jako celobuněčných, nelze předpokládat zlepšení současného stavu. Pouze důsledně prováděná aktivní surveillance, používání nové generace více imunogenních pertussových očkovacích látek a opakované přeočkovávání starších věkových skupin populace může přinést žádoucí výsledky.
Study objectives: To analyze the incidence of pertussis in the Czech Republic, influencing factors and, in particular, the effect of vaccination on pertussis morbidity, clinical seriousness of the disease and circulation of Bordetella pertussis in the population. To study the causes of defective diagnosis and reporting and to propose remedial measures. Methods: Data on pertussis morbidity were obtained from the archives of the National Institute of Public Health and the public health information systems ISPO and EPIDAT. Mortality data were taken from the above sources and literature. The case definition was used as specified in the Methodical Guidance for Pertussis Surveillance and the EC Directive. Laboratory diagnosis was based on culture and serology. An at least fourfold increase in the serum antibody titer found within an experiment was considered as a positive result. Results: Pertussis together with diphteria and measles used to be among the most dangerous infections in childhood. The oldest mortality data date back to 1890 when 62 deaths per 100,000 population were reported. In 1951, the death rate still reached 3.6/100,000. The pertussis morbidity peaked in 1955 with 540 cases per 100,000 population. Vaccination against pertussis since the early 1950’s led to a rapid reduction of morbidity in children. Nevertheless, higher pertussis morbidity rates were observed at 2–4-year intervals (in the so- called epidemic years). The lowest morbidity rates were reported during the 1980’s. However, a stable upward trend has been observed over the following years. In 2006, a neonate died from pertussis. The age specific morbidity rates in 1980 through 2000 were highest in children under one year of age. This fact together with the regularly increased morbidity rates observed at 2–3-year intervals indicate that Bordetella pertussis still circulates in the population. While in the 1980’s, the cases of pertussis were reported almost exclusively in children under one year of age, in the 1990’s, they became more common also among children 1–4 years of age and started to be prevalent in children 10–14 years of age since 2001. Conclusion: A high immunisation coverage (97 %) with five doses of high quality whole-cell vaccine of Czech origin introduced into practice in 1958 played a crucial role in the reduction of pertussis morbidity from more than 500/100,000 in the mid-1950’s to less than 0.5/100,000 in the 1980’s. Nevertheless, this strategy did not lead to elimination of the causative agent in the population. It is evident that the current immunization scheme with the use of the available vaccines cannot solve the epidemiological situation. Since the efficacy of the currently available acellular pertussis vaccines is, at the best, the same as that of the whole-cell vaccines, any improvement of the current status cannot be expected. Only effective active surveillance, the use of new more immunogenic pertussis vaccines and revaccination of older age groups can result in desirable outcomes.
- MeSH
- epidemiologické metody MeSH
- infekce bakteriemi rodu Bordetella diagnóza epidemiologie prevence a kontrola MeSH
- interpretace statistických dat MeSH
- lidé MeSH
- morbidita trendy MeSH
- pertuse diagnóza epidemiologie prevence a kontrola MeSH
- pertusová vakcína aplikace a dávkování imunologie MeSH
- Check Tag
- lidé MeSH
- Geografické názvy
- Česká republika MeSH
- MeSH
- Achillova šlacha MeSH
- dítě MeSH
- fibula chirurgie MeSH
- fixace fraktury MeSH
- hojení ran MeSH
- lidé MeSH
- metody MeSH
- mladiství MeSH
- nestejná délka dolních končetin MeSH
- osteomyelitida komplikace MeSH
- osteotomie přístrojové vybavení MeSH
- poliomyelitida komplikace MeSH
- pooperační komplikace MeSH
- terapie cvičením MeSH
- tibie chirurgie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
Cieľ práce: Hodnotenie účinku McKenzie metódy v porovnaní s klasickou fyzioterapiou u pacientov s chronickou bolesťou cervikálnej chrbtice. Sledovanie tonusu m. trapezius v zaťažení a stupňa dizability. V skupine liečenej McKenzie metódou súvis fenoménu centralizácie s hodnotami tonusu m. trapezius. Vzorka: Výskumná vzorka pozostávala z 55 pacientov, ktorí boli stratifikovaným výberom rozdelení do dvoch skupín. Skupina A bola liečená McKenzie metódou s pridaním klasickej fyzioterapie (n=30), skupina B bola liečená výlučne klasickou fyzioterapiou (n=25). Kontrolnú skupinu C predstavovali zdraví jedinci (n=24) bez liečebného zásahu. Metódy: Na hodnotenie dizability bol použitý Neck disability index/NDI/. Metódou na meranie tonusu m. trapezius z oblasti C7 bola povrchová EMG prostredníctvom 2-kanálového prístroja EMG - Biofeedback 2000 x-pert /Firma Schuhfried/, hodnoty tonusu boli merané v μV, v zaťažení, počas vykonávania opakovanej elevácie lopatiek. Hodnotený bol fenomén centralizácie prostredníctvom 4-stupňovej škály. Výsledky: V hodnotení celkového skóre dotazníka /NDI/ a v hodnotení tonusu m. trapezius v zaťažení medzi skupinami A, B neboli po celú dobu sledovania zaznamenané signifikantné rozdiely. Pred liečbou boli hodnoty tonusu m. trapezius u zdravých signifikantne nižšie (p<0,05) v porovnaní so skupinami A, B. V skupine A bol zaznamenaný fenomén centralizácie po týždni u 60 %, po mesiaci u 100 % pacientov. Po mesiaci v skupinách A a B došlo k signifikantnému ústupu disability (p<0,05). Nedošlo k signifikantnému poklesu tonusu m. trapezius. Tri mesiace po liečbe bol zaznamenaný u skupín A a B ďalší pokles disability(p<0,05). V hodnotení tonusu m. trapezius v zaťažení pred liečbou boli hodnoty tonusu m. trapezius u zdravých signifikantne nižšie (p<0,05). Tri mesiace po liečbe došlo k signifikantnému poklesu v skupinách A a B (p< 0,05) a zároveň neboli zistené signifikantné rozdiely oproti zdravým. Záver: V predkladanej štúdii sa nám podarilo signifikantne redukovať dizabilitu po mesiaci a ďalej po troch mesiacoch liečby v skupinách A a B a signifikantne redukovať tonus m. trapezius v zaťažení, po troch mesiacoch liečby u oboch skupín A a B. Nebola potvrdená dynamika fenoménu centralizácie s dynamickou poklesu tonusu m. trapezius v skupine A.
The objective of the work: The comparison of the effect of special rehabilitation the McKenzie method and classic physiotherapy in patients with chronic pain in cervical spine region, based on muscle tone reduction (m. trapezius) evaluated by means of the surface EMG, decline of disability. In the group of patients treated by McKenzie method the monitoring of the association of the centralization phenomenon with m. trapezius tone values was conducted. Patient sample: Our patient research sample consisted of 55 patients who were divided into two groups by a stratified selection. The group A was treated by McKenzie method (n=30). The group B was treated by classical physiotherapy (n=25). The control group C consisted of healthy individuals (n=24) without any therapeutic intervention. Methods used: For the measurement of disability we used Neck disability index /NDI/. For the measurement of muscle tone we used the surface EMG, applying two-channel EMG apparatus- Biofeedback 2000 x-pert. The muscle tone values were measured in μV, on loaded, during performing repetition elevation of shoulder blade. Assessment of centralization phenomenon was used. Results: Before treatment In overall score evaluation in both groups A, B there were no significant differences recorded. The m. trapezius muscle tone values in healthy individuals C, were significantly lower (p<0.05), in comparison with groups A, B. In the A group the centralization phenomenon was recorded after one week in 60 %, after one month in 100 % patiens. One month after the treatment in both groups A, B a significant decline of disability occurred (p<0.05). There was no significant decrease of m. trapezius tone. Three months after the treatment further disability decline was recorded in groups A, B. In the assessment of m. trapezius muscle tone in μV in both groups occurred (p<0.05). At the same time the measured muscle tone values in μV were comparable with values in healthy individuals without pain. Conclusion: In the presented study we report how we managed to significantly reduce the of disability one month and three month after the treatment in groups A,B( p< 0.05) and also to significantly reduce m. trapezius tone reduction under loading three months after the treatment in both groups A, B (p< 0.05). The association between the centralization phenomenon and m. trapezius tone decrease was not proven.
- Klíčová slova
- povrchová EMG, cervikobrachiální syndrom,
- MeSH
- bolesti zad * rehabilitace MeSH
- chronická bolest rehabilitace MeSH
- dospělí MeSH
- elektromyografie metody statistika a číselné údaje MeSH
- kosterní svaly fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- měření bolesti statistika a číselné údaje MeSH
- postura těla MeSH
- posuzování pracovní neschopnosti MeSH
- prospektivní studie MeSH
- průzkumy a dotazníky MeSH
- spokojenost pacientů MeSH
- statistika jako téma MeSH
- stupeň závažnosti nemoci MeSH
- svalový tonus * fyziologie MeSH
- techniky fyzikální terapie * statistika a číselné údaje MeSH
- terapie cvičením MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- srovnávací studie MeSH
Deficit kognitivních funkcí je považován za jádrové postižení u schizofrenie, které koreluje s výslednými stavy onemocnění více než psychotické příznaky. Kognitivní oslabení je přítomno v prodromálních fázích onemocnění, u prvních epizod i v chronických fázích. Terapeutické možnosti jeho zmírnění jsou limitované. Jednak se jedná o nefarmakologické intervence (kognitivní remediace, neurostimulace) a jednak o farmaka, která působí na dopaminový, glutamátový, serotoninový, cholinergní nebo GABA neurotransmiterový systém. V praxi jsou nejdostupnějšími prokognitivními farmaky antipsychotika, jejich klinický efekt však zůstává malý. Nový serotonin-dopaminový antagonista lurasidon má unikátní receptorový profil, který naznačuje možnost pozitivního efektu na kognici: antagonismus 5-HT7 a α2C receptorů, agonismus 5-HT1A , nízká vazba k D4 receptorům. Lurasidon v animálních studiích spolehlivě zlepšoval experimentálně narušené funkce paměti a učení a pozitivně ovlivňoval neuronální plasticitu. Klinická data o prokognitivním účinku lurasidonu se opírají o krátkodobé srovnání se ziprasidonem a především vycházejí z dvojitě slepé studie s quetiapinem XR. Lurasidon v krátkodobé i dlouhodobé terapii signifikantně lépe než komparátor ovlivnil kognitivní výkon pacientů se schizofrenií. Zmírnění kognitivního deficitu po léčbě lurasidonem bylo doprovázeno zlepšením funkční kapacity pacientů.
Cognitive deficit is considered as the core impairment in schizophrenia, it correlates with outcomes more than psychotic symptoms. Cognitive dysfunction can be found in the prodromal phases, in first episodes and in chonic phases of the illness. Therapeutic options are limited, nonpharmacological interventions (cognitive remediation, neurostimulation) or drugs that modulate dopaminergic, glutamatergic, serotoninergic, cholinergic, or GABA neurotransmitter system can be used. In clinical practice, the most available procognitive drugs are antipsychotics; however, their clinical effect is small. New serotonin-dopamine antagonist lurasidone has a unique receptor profile that suggests positive effect on cognition: 5-HT7 and α2C receptor antagonism, 5-HT1A agonism, low affinity to D4 receptors. Lurasidone in animal studies reliably improved experimentally impaired memory and learning functions and enhanced neural plasticity. Clinical data on the procognitive efficacy of lurasidone are based on a short-term comparison with ziprasidone and mainly on a double-blind study with quetipine XR. Lurasidone was superior to the comparators in cognitive performance of schizophrenia patients in both short- and long-term treatment. Reduction of cognitive deficit was associated with improvement of patients ́ functional capacity.