Removal of Cadmium, Lead and Arsenic from Water by Lactic Acid Bacteria

A number of contaminants such as arsenic, cadmium and lead are released into the environment from natural and anthropogenic sources contaminating food and water. Chronic oral ingestion of arsenic, cadmium and lead is associated with adverse effects in the skin, internal organs and nervous system. In addition to conventional methods, biosorption using inactivated biomasses of algae, fungi and bacteria has been introduced as a novel method for decontamination of toxic metals from water. The aim of this work was to evaluate the applicability of lactic acid bacteria as tools for heavy metal removal from water and characterize their properties for further development of a biofilter. The results established that in addition to removal of mycotoxins, cyanotoxins and heterocyclic amines, lactic acid bacteria have a capacity to bind cationic heavy metals, cadmium and lead. The binding was found to be dependent on the bacterial strain and pH, and occurred rapidly on the bacterial surface, but was reduced in the presence of other cationic metals. The data demonstrates that the metals were bound by electrostatic interactions to cell wall components. Transmission electron micrographs showed the presence of lead deposits on the surface of biomass used in the lead binding studies, indicating involvement of another uptake/binding mechanism. The most efficient strains bound up to 55 mg Cd and 176 mg Pb / g dry biomass. A low removal of anionic As(V) was also observed after chemical modification of the cell wall. Full desorption of bound cadmium and lead using either dilute HNO₃ or EDTA established the reversibility of binding. Removal of both metals was significantly reduced when biomass regenerated with EDTA was used. Biomass regenerated with dilute HNO3 retained its cadmium binding capacity well, but lead binding was reduced. The results established that the cadmium and lead binding capacity of lactic acid bacteria, and factors affecting it, are similar to what has been previously observed for other biomasses used for the same purpose. However, lactic acid bacteria have a capacity to remove other aqueous contaminants such as cyanotoxins, which may give them an additional advantage over the other alternatives. Further studies focusing on immobilization of biomass and the removal of several contaminants simultaneously using immobilized bacteria are required.

Lentotuhkan fraktiointi sähkösuodattimella ja Ion Blast -menetelmällä

Diplomityö on osa YTI-tutkimuskeskuksessa vuosina 2002 - 2004 toteutettavaa Jätekompostit rakeiksi tuhkaseostuksella -käyttöarvon parantaminen -projektia. Työssä tutkittiin Etelä-Savon Energia Oy:n Pursialan voimalaitoksen lentotuhkan fraktioimista voimalaitoksen nykyisellä 3-kenttäisellä sähkösuodattimella ja pilot-mittakaavaisella Ion Blast -koelaitteistolla. Sähkösuodattimen koeajojen aikana muuteltiin sen ajotapaa mm. CBO -suhteen ja maksimijänniteasetuksen avulla. Ion Blast -koelaitteistolla tutkittiin mahdollisuuksia voimalaitoksen lentotuhkan puhdistamiseksi raskasmetalleista. Lentotuhkan hyötykäyttöä vaikeuttaa sen raskasmetallipitoisuuksien suuri vaihtelu. Ongelmallisin raskasmetalli puuperäisessä lentotuhkassa on kadmium, jonka lannoitelainsäädännön raja-arvo on tällä hetkellä 3 mg/kg. Sähkösuodattimella tehtyjen fraktiointikokeiden perusteella voidaan todeta raskasmetallipitoisuuksien olevan pienimmillään sähkösuodattimen 1-kentässä ja suurimmillaan 3-kentässä. Tämä johtuu siitä, että 1-kenttään kerääntyy hiukkaskooltaan suurimmat lentotuhkahiukkaset ja 3-kentässä on mukana enemmän pienhiukkasia sisältävää tuhkaa. Lannoitteeksi menevän tuhkan Cd-pitoisuutta voidaan vähentää parhaimmillaan jopa 70 % sähkösuodattimella fraktioimalla. Muiden raskasmetallien pitoisuudet eivät vähene aivan yhtä paljon. Sähkösuodattimella voidaan tulosten perusteella fraktioida lentotuhkaa. Sähkösuodattimella ei kuitenkaan voida varmasti saavuttaa alle 3 mg/kg Cd-pitoisuuksia polttoaineen laadunvaihtelun vuoksi. Ion Blast -koelaitteiston tulokset tukevat sähkösuodattimella tehtyjä kokeita. Erottimen jännitteen kasvaessa raskasmetalleja sisältävien hiukkasten erotusaste kasvaa. Ion Blast -laitteistolla tehdyissä kokeissa myös Cd-pitoisuus oli korkeimmillaan pienimmän raeluokan hiukkasissa ja laski sitten raeluokan suurentuessa. Ion Blast -laitteisto ei kuitenkaan sellaisenaan ole hyvä fraktiointiin. Se on liian tehokas, jolloin se puhdistaa tehokkaasti myös raskasmetalleja sisältävät pienhiukkaset. Jos laitetta aiotaan käyttää fraktiointiin, tulisi sen rakennetta muuttaa.

Cell wall maturation of Arabidopsis trichomes is dependent on exocyst subunit EXO70H4 and involves callose deposition.

Arabidopsis (Arabidopsis thaliana) leaf trichomes are single-cell structures with a well-studied development, but little is understood about their function. Developmental studies focused mainly on the early shaping stages, and little attention has been paid to the maturation stage. We focused on the EXO70H4 exocyst subunit, one of the most up-regulated genes in the mature trichome. We uncovered EXO70H4-dependent development of the secondary cell wall layer, highly autofluorescent and callose rich, deposited only in the upper part of the trichome. The boundary is formed between the apical and the basal parts of mature trichome by a callose ring that is also deposited in an EXO70H4-dependent manner. We call this structure the Ortmannian ring (OR). Both the secondary cell wall layer and the OR are absent in the exo70H4 mutants. Ecophysiological aspects of the trichome cell wall thickening include interference with antiherbivore defense and heavy metal accumulation. Ultraviolet B light induces EXO70H4 transcription in a CONSTITUTIVE PHOTOMORPHOGENIC1-dependent way, resulting in stimulation of trichome cell wall thickening and the OR biogenesis. EXO70H4-dependent trichome cell wall hardening is a unique phenomenon, which may be conserved among a variety of the land plants. Our analyses support a concept that Arabidopsis trichome is an excellent model to study molecular mechanisms of secondary cell wall deposition.

Uusien ympäristölupien ja ympäristölainsäädännön muutosten vaikutukset savukaasunpuhdistuslaitekantaan

Työn tarkoituksena oli selvittää Alstom Finland Oy:n pääasiakkaiden ympäristö-lupatilanne sekä tarkastella, miten Alstomin toimittamat hiukkastenpuhdistuslait-teet täyttävät muuttavat lainsäädännön vaatimukset. Lisäksi työssä arvioitiin lai-tosten hiukkaspäästöjen vähentämisestä syntyvää savukaasunpuhdistuslaitteiden investointitarvetta. Työn teoriaosuus sisältää katsauksen ympäristölupakäytäntöön sekä Valtioneu-voston asetuksiin, jotka koskevat laitosten hiukkaspäästöjä. Lisäksi työssä on kä-sitelty parhaan käytettävissä olevan tekniikan mukaisia hiukkaspäästörajoja ja tekniikoita sekä hiukkasten muodostumista että raskasmetallien sitoutumista hiukkasiin. Kaikkiaan työssä mukana olevia laitoksia oli 49, joista tarkemmin tarkasteltiin 12 laitosta. Suurin osa laitoksista ei ollut saanut tai hakenut ympäristönsuojelulain mukaista ympäristölupaa, joten niillä on velvollisuus hakea lupaa siirtymäsään-nöksen mukaisesti vuoden 2004 loppuun mennessä. Tarkemmassa tarkastelussa olevien laitosten hiukkaspäästömittaustuloksia vertailtiin nykyisiin sekä uu-siin/oletettuihin ympäristölupien hiukkaspäästörajoihin. Tarkastelussa mukana olevasta seitsemästä soodakattilalaitoksesta, joilla ei vielä ollut uutta ympäristölu-paa, 43 % ylitti arvioidun uuden luparajan 50 mg/m3(n):ssa ja kolmesta meesauu-nia käyttävästä laitoksesta yksi sekä viidestä muusta kattilasta kaksi.

Quantitative elemental analysis of dry-ashed bark and wood samples of birch, spruce and pine from south-western Finland using PIXE

A total of over 200 different samples of bark and wood of Silver birch, Norway spruce and Scots pine were analysed. Samples were taken from several areas in western Finland, some with known sources of atmospheric heavy metal emission (Harjavalta, Ykspihlaja). Also analytical data for pine needles from some sites are reported. The chemical analyses were performed by thick-target particle-induced X-ray emission (PIXE) spectrometry after preconcentration by dry ashing of samples at 550oC. The following elements were quantified in most of the samples: P, S, K, Ca, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Cd, Ba and Pb. The ash percentage and the chemical composition of ashes of different wood materials were also obtained, as dry ashing was used in the analytical procedure. The variations in elemental concentrations in wood and bark of an individual tree, expressed as RSDs, were mostly in the range 10 – 20 %. For several trees of the same species sampled from small areas (< 1 ha), the variations in elemental concentrations were surprisingly high (RSDs 20 – 50 %). In the vicinity of metal plants, effects of strong atmospheric heavy metal pollution (pollution factor above 100) were observed in pine bark. The increase of heavy metal content in wood samples from the same sites was quite small. Elemental concentrations in ashes of bark and wood, from areas with no local source of atmospheric pollution, were relatively uniform. Based on this observation an alternative way of demonstrating atmospheric pollution of tree bark is discussed.

Espectroscopia óptica de vidros fluoroindatos dopados com íons Er3+ e Yb3+

Optical spectroscopy in the 400-1700nm wavelength range was performed on rare earth doped heavy metal fluoride (HMF) glasses. In the present work In-based fluoride glasses with a fixed 2 mol % YbF3 concentration and an ErF3 content ranging from 0 to 8 mol % were investigated. According to the experimental spectroscopic data a dependence in the absorption coefficient, the photoluminescence intensity and in the radiative lifetime could be verified as a function of the ErF3 content. In addition, at liquid nitrogen temperature, light emission corresponding to indirect transitions in the infrared energy range could be easily observed as a consequence of the low phonon frequency characteristic of this class of fluoride glasses. For all the studied compositions, strong upconversion to the green and red light was observed by pumping these Er3+- and Yb3+-doped HMF glasses with 790 and 980nm photon sources.

Metais pesados em águas superficiais como estratégia de caracterização de bacias hidrográficas

The input of heavy metals concentrations determinated by ICP-AES, in samples of the Cambé river basin, was evaluated by using the Principal Component Analysis. The results distinguishes clearly one site, which is strongly influenced by almost all elements studied. Special attention was given to Pb, because of the presence of one battery industry in this area. Some downstream samples were associated with the same characteristics of this site, showing residual action of contaminants along the basin. Other sites presented influence of soil elements, plus Cr near a tannery industry. This study allowed to distinguish different sites in the upper basin of the Cambé (Londrina-PR-BR), in accordance to elements input.

Avaliação quimiométrica da distribuição de metais pesados em composto de lixo urbano domiciliar

The main obstacle to the use of compost from urban waste in agriculture is the presence of heavy metals. Once in the soil, their effect is accumulative and they may contaminate crops and water. The present study reports the evaluation of the chemical distributions of Cu, Pb, Mn and Zn in three different sized fractions (unsieved, < 1,18mm and > 1,18mm) of compost, by means of a sequencial extraction procedure and a chemometric analysis of the total content of all metals in each fraction. The pattern recognition methods showed significant differences in total heavy metal contents for the different fractions. The finest one was the most contaminated. Meanwhile, this fraction presented lower amounts of metals in avaliable forms. This behavior can be attributed to the presence of metal particles in their elemental states in this fraction.

Especiação de metais-traço em sedimentos de florestas de manguezais com Avicennia e Rhizophora

Speciation studies of Fe, Cr, Co, Ni and Cu on reactive fraction (adsorved on oxides, hydroxides, carbonates and clay minerals) and pyrite were performed in Avicennia schaueriana and Rhizophora mangle sediments from Amapá shoreline-Brazil. The soil under Avicennia showed a higher heavy metal concentration in reactive fraction than under Rhizophora. The soil under Rhizophora showed low heavy metal bioavailability, having an increasing association with pyrite across sediment section.

Utilização de modelos físico-químicos de adsorção no estudo do comportamento do cobre em solos argilosos

It was evaluated the applicability of Langmuir, Freundlich and Temkin models to copper adsorption in three classes of soils. Fractions of each soil were added to test tubes containing growing concentrations of the metal in solution. The tubes were shaken and the copper concentrations were determined in the extracts by atomic absorption spectrometry (AAS). The models offered a good fit for the experimental data indicating that presence of silicated clay had high influence on copper sorption. The Langmuir isotherm showed high influence of the organic matter in the absorption phenomenon. It was evidenced the importance of further studies related to Temkin model.

Geoquímica e índice de geoacumulação de mercúrio em sedimentos de superfície do estuário de Santos - Cubatão (SP)

The concentrations of mercury in surface sediments (<63mum fraction) from Santos-Cubatão Estuary, located in State of São Paulo, southeast Brazil, were determined to obtain the level of contamination in this highly polluted area. Fifteen stations distributed though seven rivers were sampled (156 samples collected) from September 1997 to August 1998 (12 stations sampled monthly) and during March, June, September and December 1998 (three stations sampled quarterly). The levels of mercury varied from 0.10 to 6.77 ppm, with the index of geoaccumulation of the rivers varying between grades 1 and 3 (annual average). The Cubatão is the most polluted river and the main agent of Hg dispersion in the study area. Geochemical data revealed that Hg levels in surface from Santos-Cubatão Estuary at present are as elevated as in past (for instance, by comparison 1980's), when Cubatão city was known as one of the most polluted cities in the world.

Remoção de metais pesados de efluentes industriais por aluminossilicatos

This review had as aim the bibliography research for the use of aluminosilicates to remove heavy metals from wastewaters. Advanced studies based on parameters that have influence for removal of heavy metals as pH, metal concentration, effect of ligants and removal capacity of zeolites and clays, were reported. These studies demonstrate that aluminosilicates can be successfully used for the removal of heavy metals under the optimized conditions.

Relato de uma experiência pedagógica no ensino de química: formação profissional com responsabilidade ambiental

The toxic heavy metals can not be transformed in other less toxic substances as organic wastes through chemical process. Various chemistry courses at Faculty of Philosophy, Sciences and Humanities (FFCLRP/USP) use heavy metals in their experimental classes. In this context, a course were created: "Heavy Metal Wastes generated in the teaching and research laboratories: disposal or recovery" and has a specific goal to capacitate the students to define the adequate strategy for disposal or recovery of the chemical wastes, in particular heavy metals, through an interdisciplinary approaching. This course was given to 25 students during the second semester of 2000 and 2001. The environmental responsibility desired for the professional and citizen can be promoted.

Distribuição de metais pesados em sedimentos do sistema estuarino da Ilha de Vitória-ES

Heavy-metal concentration in sediment is an important parameter for identifying pollution sources and assessing pollution levels in aquatic ecosystems. In this context, the present study aimed at determining concentrations of heavy metals in sediments from the Vitória estuarine system, Brazil. Twenty nine stations were surveyed to assess the spatial distribution of heavy metals. The metals for silt-clay fractions (<63 µm) were analyzed through atomic absorption spectrometry. A discriminant analysis segregated the stations in four groups representing four areas within the estuarine system. The Espírito Santo Bay showed the lowest metal concentrations, while the Vitória harbor canal showed the highest. We concluded that concentrations of heavy metals reflect natural conditions and the contribution of human activities from sewage and industrial effluents. It was not possible to directly associate metal concentrations to specific pollution sources.

Quimissorção de cátions divalentes em sílica gel modificada com ácido tioglicólico: a influência do pH e força iônica

A novel type of heavy metal adsorbent was prepared by the covalent grafting of thioglycolic acid molecules on a silica gel surface previsiouly modified with 3-aminopropyltrimethoxysilane. The amount of thioglycolic acid immobilized was 1.03 mmol per gram of silica. This material displayed a chelating moiety containing nitrogen, sulfur, and oxygen basic centers which are potentially capable of extracting from aqueous solutions cations such as Cu(II), Ni(II), Co(II), influenced by pH and ionic strength. This process of extraction was carried out by the batch method when similar chemisorption isotherms were observed for all cations. A modified Langmuir equation describes the experimental data.