Confocal microscopy 3D imaging and bioreactivity of La Palma volcanic ash particles.

In September 2021 an eruption began of Cumbre Vieja, La Palma (Spain) that lasted 3 months. Previous studies have shown that volcanic ash particles can be associated with adverse effects on human health however, the reasons for this are unclear. Particle shape has been shown to contribute to cellular uptake in prostate cancer cells. Hence we aimed to study 3D structure, elemental composition and effects on cultured lung cells of particles collected from the La Palma volcanic eruption. 3D imaging of PM10 sized and below particles was performed using a LEXT OLS4100 confocal microscope (Olympus Corporation, Japan). A Zeiss EVO 50 (Carl Zeiss AG, Germany) Scanning Electron Microscope (SEM) was used to assess elemental composition. In addition, volcanic particle concentration dose response for pneumococcal adhesion to A549 human alveolar epithelial cells was investigated. Confocal microscopy showed that some PM10 and below sized particles had sharp or angular 3D appearance. SEM x-ray analysis indicated silicate particles with calcium, aluminium and iron. We observed increased colony forming units indicating increased Pneumococcal adhesion due to exposure of cells to volcanic particles. Thus in addition to the toxic nature of some volcanic particles, we suggest that the observed sharp surface particle features may help to explain adverse health effects associated with volcanic eruptions.

Iron and total organic carbon shape the spatial distribution pattern of sediment Fe(III) reducing bacteria in a volcanic lake, NE China.

Fe(III) reducing bacteria (FeRB) play a vital role in the biogeochemical cycle of Fe, C and N in nature. The volcanic lake can be considered as an ideal habitat for FeRB. Here, we investigated the diversity and spatial distribution of FeRB in sediments of Wenbo lake in Wudalianchi volcano based on culture-dependent and independent methods. A total of 28 isolates affiliated with the genera of Enterobacter, Bacillus, Pseudomonas and Clostridium were obtained from 18 sediment samples. We detected 783 operational taxonomic units (OTUs) belonged to FeRB using high high-throughput sequencing, and the dominant phyla were Proteobacteria (3.65%), Acidobacteria (0.29%), Firmicutes (10.78%). The representative FeRB genera such as Geobacter, Pseudomonas, Thiobacillus and Acinetobacter distributed widely in Wenbo lake. Results showed that the diversity and abundance of FeRB declined along the water-flow direction from Libo to Jingbo. In contrast, the FeRB diversity decreased and the FeRB abundance increased along with depth transect of sediments. It was found that the dominant phylum changed from Firmicutes to Proteobacteria along the water-flow direction, while changed from Proteobacteria to Firmicutes along with the depth of sediments. RDA indicated that the FeRB distribution were driven by soluble total iron, total organic carbon, Fe(II) and Fe(III). These will provide information for understanding the role of FeRB in the elements geochemical cycles in the volcanic environment.

Naturaleza y estructura geológica del borde costero del noroeste de Costa Rica / Geological background and structure of the northwestern coastline of Costa Rica

Introducción: El noroeste de Costa Rica representa un área con una alta riqueza geológica que evidencia rocas generadas en diferentes ambientes, como plano abisal, talud continental, plataforma continental, volcánicos continentales efusivos y explosivos, volcánicos submarinos, costeros, erosivos fluviales, erosivos gravitatorios, de intrusión y el manto terrestre. Objetivo: Describir el contexto geológico actual del noroeste de Costa Rica, mediante el análisis y recopilación de datos de campo, geoquímicos, petrológicos, estructurales, paleontológicos y radiométricos con el fin de reconstruir los eventos y etapas de deformación desde el Jurásico a la actualidad. Métodos: Se hizo una recopilación bibliográfica de estudios en diversas ramas geológicas para establecer un estado del arte del extremo noroeste de Costa Rica. Resultados: La historia geológica representa el registro en rocas desde el Jurásico al Holoceno - actualidad con once etapas definidas a partir de interpretaciones petrológicas, estructurales, geocronológicas, estratigráficas y paleontológicas agrupadas en tres etapas de depositación y afectadas por cuatro fases tectónicas compresivas. Conclusiones: Las etapas de depositación corresponden con una primera etapa magmática con afinidad oceánica entre el Jurásico y el Cretácico Superior, una segunda etapa predominantemente sedimentaria con un rango de edad entre el Cretácico Superior y el Oligoceno, y por último una etapa volcánica efusiva - explosiva ubicada desde el Plioceno hasta la actualidad. Las fases tectónicas se asocian con diferentes eventos entre placas. La primera se dio en el Cretácico Inferior y su principal resultado visible fue la emersión de la Ofiolita de Santa Elena; la segunda sucedió del Cretácico Superior temprano al Campaniano y su reconocimiento está ligado a la posición actual de la Ofiolita de Santa Elena y sus estructuras circundantes; la tercera fase aconteció desde el Eoceno Superior hasta el Mioceno y su principal producto fue la generación del tren de pliegues sedimentarios del Golfo de Santa Elena a bahía de Salinas; y por último se presenta una fase Cuaternaria que originó el eje de basculamiento de los productos piroclásticos frente a la cordillera volcánica de Guanacaste.

Introduction: The Costa Rican northwestern coastline has a wide geological uniqueness that exhibits rocks from different environments such as abyssal plane, continental slope, continental platform, volcanic eruptions (effusive, explosive, and submarine), coastal, erosional (fluvial and gravitatory), intrusions, and upper mantle rocks. Objective: To present the geologic state of the art of the northwestern coastline of Costa Rica through the bibliographic review of geochemical, petrologic, structural, paleontological and geochronological data. Methods: A bibliographic revision was done to propose a state of the art of northwestern coastline of Costa Rica. Results: The geologic record shows eleven stages from the Jurassic to the Holocene. These stages were regrouped from petrologic, structural, geochronologic, stratigraphic and paleontological interpretations in three depositional stages and four compressive tectonic phases. Conclusions: The first depositional stage is volcanic with oceanic affinity between the Jurassic and Upper Cretaceous. The second has a sedimentary predominance with an age range between the Upper Cretaceous and the Miocene. The last depositional stage is a volcanic (effusive and explosive) from the Pliocene until the present. The tectonic phases are associate with different interactions between tectonic plates. The first phase triggered the Santa Elena Ophiolite obduction during the Early Cretaceous. The second phase occurred in the Early Upper Cretaceous - Campanian and is recognized by its current position and surrounding structures. The third phase lasted from the Upper Eocene until the Miocene and its main result was the folding of the Bahía de Salinas sedimentary rocks. Finally, the Quaternary phase created a tilt axis and the aperture for the deposition of pyroclastic density currents in front of the Guanacaste volcanic ridge.

Metal concentrations in recent ash fall of Popocatepetl volcano 2016, Central Mexico: Is human health at risk?

The present study addresses the metal concentration pattern and associated human health risks in ash samples of Popocatepetl volcano. In this regard, 12 ash samples from different regions of Puebla City were collected and analyzed for 28 major and trace metals, out of which exclusively 8 metals of potential risk (Cd, Co, Cr, Cu, Mn, Ni, Pb & Zn) were selected for human health risk validation. The metal concentration pattern showed an enriching trend for ferromagnesium and carbonate elements compared to previous ash eruptions. Enrichment factor and geoaccumulation indices displayed a least significant enhancement of metals from baseline concentrations. More likely, the potential ecological risk index suggested no harmful biological effects due to the presence of these metals in ash. Concurrently, in the human health risk assessment model, the hazard quotient and hazard index values < 1 indicated safe levels and no carcinogenic effects. All-inclusive, this study highlights the context of metals in ash fall of Popocatepetl which presents no adverse effects over the human population.

Influence of the submarine volcanic eruption off El Hierro (Canary Islands) on the mesopelagic cephalopod's metal content.

This work investigates whether a submarine volcanic eruption off El Hierro (Canary Islands) in October 2011 influenced the metal contents of two deep water cephalopod species: Abraliopsis morisii and Pyroteuthis margaritifera. This was assessed by comparing metal contents in specimens collected off the island of El Hierro and in the neighbouring islands of La Palma and Tenerife during an experimental deep water fishing trip. The concentration of 20 heavy metals was analyzed in 180 specimens of A. morisii and P. margaritifera collected around the three islands to test for inter-island differences for each species and metal. While both species showed geographical differences in metal concentrations, the main finding was that A. morisii could be a bioindicator species for metals such as Li, Sr and Ca.

Occupational exposure to Mount Etna's basaltic dust: Assessment of mutagenic and cytotoxic effects.

Basalt and volcanic ash are natural constituents of the ground surrounding volcanic areas such as Mount Etna. The dust may be daily inhaled by the general population as well as by several types of workers, such as construction workers. In this experiment, we analyzed the potential mutagenic and cytotoxic effects of the materials used in construction industry, excavated from Mt. Etna. Ground basalt (A), volcanic ash (B), mixed basalt and cement (C) and cement (D) were studied with Ames test, for mutagenic assessment and with MMT assay for cytotoxic evaluation. The Ames test revealed that cement (sample D), showed a higher and significant mutagenicity than the samples A, B and C. MTT assay showed that samples C and D had a slightly more negative impact on cell viability than A and B. In conclusion, no particular risks seem to exist for construction industry workers, while the exploitation of cement and cement mixed with basalt seems to be a risk for workers, given the high percentage of silica and iron.

Heavy metals in the volcanic environment and thyroid cancer.

In the last two decades thyroid cancer incidence has increased worldwide more than any other cancer. Overdiagnosis of subclinical microcarcinomas has certainly contributed to this increase but many evidences indicate that a true increase, possibly due to environmental factors, has also occurred. Thyroid cancer incidence is markedly increased in volcanic areas. Thus, the volcanic environment is a good model to investigate the possible factors favoring thyroid cancer. In the volcanic area of Mt. Etna in Sicily, as well as in other volcanic areas, a non-anthropogenic pollution with heavy metals has been documented, a consequence of gas, ash and lava emission. Soil, water and atmosphere contamination, via the food chain, biocontaminate the residents as documented by high levels in the urines and the scalp hair compared to individuals living in adjacent non-volcanic areas. Trace amounts of metals are essential nutrients but, at higher concentrations, can be toxic for living cells. Metals can behave both as endocrine disruptors, perturbing the hormonal system, and as carcinogens, promoting malignant transformation. Similarly to other carcinogens, the transforming effect of heavy metals is higher in developing organisms as the fetus (contaminated via the mother) and individuals in early childhood. In the last decades environment metal pollution has greatly increased in industrialized countries. Although still within the "normal" limits for each single metal the hormesis effect (heavy metal activity at very low concentration because of biphasic, non linear cell response) and the possible potentiation effect resulting from the mixture of different metals acting synergistically can explain cell damage at very low concentrations. The effect of metals on the human thyroid is poorly studied: for some heavy metals no data are available. The scarce studies that have been performed mainly focus on metal effect as thyroid endocrine disruptors. The metal concentration in tissues has been rarely measured in the thyroid. Heavy metal accumulation and metabolism in the thyroid or the carcinogenic activity of different doses and different speciation of metals has not been investigated. These studies are now warranted to better understand thyroid biology and heavy metal role in human thyroid carcinogenesis.

Dynamics of natural contamination by aluminium and iron rich colloids in the volcanic aquifers of Central Italy.

The dynamics of natural contamination by Al and Fe colloids in volcanic aquifers of central-southern Italy were investigated. Localized perched aquifers, and their relative discharges, are strongly affected by the presence of massive suspended solids, which confer a white-lacteous coloration to the water. This phenomenon occasionally caused the interruption of water distribution due to the exceeding of Al and Fe concentrations in aquifers exploited for human supply. The cause was ascribed to water seepage from perched aquifers. Water discharges affected by such contamination was investigated for the Rocca Ripesena area (north-eastern sector of Vulsini Volcanic District) and for the Rianale Stream Valley (Roccamonfina Volcanic Complex). Hydrogeological survey of both areas confirmed the presence of perched aquifers not previously considered due to their low productivity. Pluviometric data and chemical parameters were periodically monitored. Water mineralization decreased with increasing rainfall, conversely Al and Fe concentrations increased. Statistical analysis confirmed the dependence of all the chemical variables on rock leaching, with the sole exception of Al and Fe which were imputed to colloids mobilization from local, strongly pedogenized pyroclastic material. The similarities in hydrogeological settings and mobilization dynamics in both areas suggest that the Al and Fe colloidal contamination should be more abundant than currently known in quaternary volcanic areas.

Activity and interactions of methane seep microorganisms assessed by parallel transcription and FISH-NanoSIMS analyses.

To characterize the activity and interactions of methanotrophic archaea (ANME) and Deltaproteobacteria at a methane-seeping mud volcano, we used two complimentary measures of microbial activity: a community-level analysis of the transcription of four genes (16S rRNA, methyl coenzyme M reductase A (mcrA), adenosine-5'-phosphosulfate reductase α-subunit (aprA), dinitrogenase reductase (nifH)), and a single-cell-level analysis of anabolic activity using fluorescence in situ hybridization coupled to nanoscale secondary ion mass spectrometry (FISH-NanoSIMS). Transcript analysis revealed that members of the deltaproteobacterial groups Desulfosarcina/Desulfococcus (DSS) and Desulfobulbaceae (DSB) exhibit increased rRNA expression in incubations with methane, suggestive of ANME-coupled activity. Direct analysis of anabolic activity in DSS cells in consortia with ANME by FISH-NanoSIMS confirmed their dependence on methanotrophy, with no (15)NH4(+) assimilation detected without methane. In contrast, DSS and DSB cells found physically independent of ANME (i.e., single cells) were anabolically active in incubations both with and without methane. These single cells therefore comprise an active 'free-living' population, and are not dependent on methane or ANME activity. We investigated the possibility of N2 fixation by seep Deltaproteobacteria and detected nifH transcripts closely related to those of cultured diazotrophic Deltaproteobacteria. However, nifH expression was methane-dependent. (15)N2 incorporation was not observed in single DSS cells, but was detected in single DSB cells. Interestingly, (15)N2 incorporation in single DSB cells was methane-dependent, raising the possibility that DSB cells acquired reduced (15)N products from diazotrophic ANME while spatially coupled, and then subsequently dissociated. With this combined data set we address several outstanding questions in methane seep microbial ecosystems and highlight the benefit of measuring microbial activity in the context of spatial associations.

The in vitro respiratory toxicity of cristobalite-bearing volcanic ash.

Ash from dome-forming volcanoes poses a unique hazard to millions of people worldwide due to an abundance of respirable cristobalite, a crystalline silica polymorph. Crystalline silica is an established respiratory hazard in other mixed dusts, but its toxicity strongly depends on sample provenance. Previous studies suggest that cristobalite-bearing volcanic ash is not as bio-reactive as may be expected for a dust containing crystalline silica. We systematically address the hazard posed by volcanic cristobalite by analysing a range of dome-related ash samples, and interpret the crystalline silica hazard according to the mineralogical nature of volcanic cristobalite. Samples are sourced from five well-characterized dome-forming volcanoes that span a range of magmatic compositions, specifically selecting samples rich in cristobalite (up to 16wt%). Isolated respirable fractions are used to investigate the in vitro response of THP-1 macrophages and A549 type II epithelial cells in cytotoxicity, cellular stress, and pro-inflammatory assays associated with crystalline silica toxicity. Dome-related ash is minimally reactive in vitro for a range of source compositions and cristobalite contents. Cristobalite-based toxicity is not evident in the assays employed, supporting the notion that crystalline silica provenance influences reactivity. Macrophages experienced minimal ash-induced cytotoxicity and intracellular reduction of glutathione; however, production of IL-1ß, IL-6 and IL-8 were sample-dependent. Lung epithelial cells experienced moderate apoptosis, sample-dependent reduction of glutathione, and minimal cytokine production. We suggest that protracted interaction between particles and epithelial cells may never arise due to effective clearance by macrophages. However, volcanic ash has the propensity to incite a low, but significant, and sample-dependent response; the effect of this response in vivo is unknown and prolonged exposure may yet pose a hazard.

Validation of a continuous flow method for the determination of soluble iron in atmospheric dust and volcanic ash.

Iron is an essential micronutrient for phytoplankton growth and is supplied to the remote areas of the ocean mainly through atmospheric dust/ash. The amount of soluble Fe in dust/ash is a major source of uncertainty in modeling-Fe dissolution and deposition to the surface ocean. Currently in the literature, there exist almost as many different methods to estimate fractional solubility as researchers in the field, making it difficult to compare results between research groups. Also, an important constraint to evaluate Fe solubility in atmospheric dust is the limited mass of sample which is usually only available in micrograms to milligrams amounts. A continuous flow (CF) method that can be run with low mass of sediments (<10mg) was tested against a standard method which require about 1g of sediments (BCR of the European Union). For validation of the CF experiment, we run both methods using South American surface sediment and deposited volcanic ash. Both materials tested are easy eroded by wind and are representative of atmospheric dust/ash exported from this region. The uncertainty of the CF method was obtained from seven replicates of one surface sediment sample, and shows very good reproducibility. The replication was conducted on different days in a span of two years and ranged between 8 and 22% (i.e., the uncertainty for the standard method was 6-19%). Compared to other standardized methods, the CF method allows studies of dissolution kinetic of metals and consumes less reagents and time (<3h). The method validated here is suggested to be used as a standardized method for Fe solubility studies on dust/ash.

The submarine volcano eruption off El Hierro Island: effects on the scattering migrant biota and the evolution of the pelagic communities.

The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community.

Physicochemical and toxicological profiling of ash from the 2010 and 2011 eruptions of Eyjafjallajökull and Grímsvötn volcanoes, Iceland using a rapid respiratory hazard assessment protocol.

The six week eruption of Eyjafjallajökull volcano in 2010 produced heavy ash fall in a sparsely populated area of southern and south eastern Iceland and disrupted European commercial flights for at least 6 days. We adopted a protocol for the rapid analysis of volcanic ash particles, for the purpose of informing respiratory health risk assessments. Ash collected from deposits underwent a multi-laboratory physicochemical and toxicological investigation of their mineralogical parameters associated with bio-reactivity, and selected in vitro toxicology assays related to pulmonary inflammatory responses. Ash from the eruption of Grímsvötn, Iceland, in 2011 was also studied. The results were benchmarked against ash from Soufrière Hills volcano, Montserrat, which has been extensively studied since the onset of eruptive activity in 1995. For Eyjafjallajökull, the grain size distributions were variable: 2-13 vol% of the bulk samples were <4 µm, with the most explosive phases of the eruption generating abundant respirable particulate matter. In contrast, the Grímsvötn ash was almost uniformly coarse (<3.5 vol%<4 µm material). Surface area ranged from 0.3 to 7.7 m2 g(-1) for Eyjafjallajökull but was very low for Grímsvötn (<0.6 m2 g(-1)). There were few fibre-like particles (which were unrelated to asbestos) and the crystalline silica content was negligible in both eruptions, whereas Soufrière Hills ash was cristobalite-rich with a known potential to cause silicosis. All samples displayed a low ability to deplete lung antioxidant defences, showed little haemolysis and low acute cytotoxicity in human alveolar type-1 like epithelial cells (TT1). However, cell-free tests showed substantial hydroxyl radical generation in the presence of hydrogen peroxide for Grímsvötn samples, as expected for basaltic, Fe-rich ash. Cellular mediators MCP-1, IL-6, and IL-8 showed chronic pro-inflammatory responses in Eyjafjallajökull, Grímsvötn and Soufrière Hills samples, despite substantial differences in the sample mineralogy and eruptive styles. The value of the pro-inflammatory profiles in differentiating the potential respiratory health hazard of volcanic ashes remains uncertain in a protocol designed to inform public health risk assessment, and further research on their role in volcanic crises is warranted.

Geología de Bahía Culebra, Guanacaste, Costa Rica / Geology of Bahía Culebra, Guanacaste, Costa Rica

The geology of Culebra Bay, Guanacaste, Costa Rica, is composed of volcanic rocks of oceanic crust; marine sediments deposited on the slope, continental platform and superficial zones nearby to the coast, pyroclastic rocks inset with continental sediments and recent Quaternary deposits. At the base of the stratigraphy sequence the massive basalts outcrop, sometimes as pillow, from Nicoya complex with aphanitic texture with olivine phenocrysts, augites and plagioclases. Into the same formation are included intrusives of massive gabro with pyroxene and plagiogranites with phenocrysts of plagioclases and hornblendite. Then limestones outcrop from El Viejo formation formed by colonies of reefs and limestone rocks. The Montezuma formation is composed of fossiliferous sandstone, facies of sandstone with cross-lamination and facies of sandstone and lutites. The Dacitas Carbonal are composed of lavas with pumice clasts and alteration minerals. The Bagaces formation is composed of several eruptive events with ignimbrites and possibly of a sand volcaniclastic sedimentary deposit. At the top of the stratigraphic sequence are included, product of factors such as colluvial erosion, and beach sand, areas of mangrove sediments and alluvium.

La geología de Bahía Culebra, Guanacaste, Costa Rica, está compuesta por rocas volcánicas de corteza oceánica; sedimentos marinos depositados en el talud, la plataforma continental y zonas someras cerca de la costa; secuencias de rocas piroclásticas intercaladas con sedimentos continentales y depósitos Cuaternarios recientes. En la base de la secuencia estratigráfica afloran los basaltos masivos, algunas veces en almohadilla, del Complejo de Nicoya con textura afanítica con fenocristales de olivino, augitas y plagioclasas. Dentro de la misma Formación se incluyen intrusivos de gabro masivos con piroxenos y plagiogranitos con fenocristales de plagioclasas y hornblenda. Seguidamente afloran las calizas de la Formación El Viejo constituida por colonias arrecifales e intercalaciones calcáreas. La Formación Montezuma compuesta por facies de arenisca media fosilífera, facies de arenisca media con laminación cruzada y facies rítmicas de areniscas y lutitas. Las Dacitas Carbonal están compuestas por lavas hexagonales y variaciones brechosas con clastos de pómez y minerales de alteración. La Formación Bagaces se constituye de varios eventos eruptivos con secuencias de ignimbritas y un depósito sedimentario posiblemente pluvial de arenas volcaniclásticas. En la parte superior de la secuencia estratigrafica se incluyen los depósitos producto de factores erosivos tales como coluvios, arenas de playa, sedimentos de zonas de manglar y aluviones.

Following the kinetics: iron-oxidizing microbial mats in cold icelandic volcanic habitats and their rock-associated carbonaceous signature.

Icelandic streams with mean annual temperatures of less than 5 °C, which receive the cationic products of basaltic rock weathering, were found to host mats of iron-cycling microorganisms. We investigated two representative sites. Iron-oxidizing Gallionella and iron-reducing Geobacter species were present. The mats host a high bacterial diversity as determined by culture-independent methods. ß-Proteobacteria, Actinobacteria, α-Proteobacteria, and Bacteroidetes were abundant microbial taxa. The mat contained a high number of phototroph sequences. The carbon compounds in the mat displayed broad G and D bands with Raman spectroscopy. This signature becomes incorporated into the weathered oxidized surface layer of the basaltic rocks and was observed on rocks that no longer host mats. The presence of iron-oxidizing taxa in the stream microbial mats, and the lack of them in previously studied volcanic rocks in Iceland that have intermittently been exposed to surface water flows, can be explained by the kinetic limitations to the extraction of reduced iron from rocks. This type of ecosystem illustrates key factors that control the distribution of chemolithotrophs in cold volcanic environments. The data show that one promising sample type for which the hypothesis of the existence of past life on Mars can be tested is the surface of volcanic rocks that, previously, were situated within channels carved by flowing water. Our results also show that the carbonaceous signatures of life, if life had occurred, could be found in or on these rocks.

Miniature open channel scrubbers for gas collection.

An open channel scrubber is proposed as a miniature fieldable gas collector. The device is 100mm in length, 26 mm in width and 22 mm in thickness. The channel bottom is rendered hydrophilic and liquid flows as a thin layer on the bottom. Air sample flows atop the appropriately chosen flowing liquid film and analyte molecules are absorbed into the liquid. There is no membrane at the air-liquid interface: they contact directly each other. Analyte species collected over a 10 min interval are determined by fluorometric flow analysis or ion chromatography. A calculation algorithm was developed to estimate the collection efficiency a priori; experimental and simulated results agreed well. The characteristics of the open channel scrubber are discussed in this paper from both theoretical and experimental points of view. In addition to superior collection efficiencies at relatively high sample air flow rates, this geometry is particularly attractive that there is no change in collection performance due to membrane fouling. We demonstrate field use for analysis of ambient SO(2) near an active volcano. This is basic investigation of membraneless miniature scrubber and is expected to lead development of an excellent micro-gas analysis system integrated with a detector for continuous measurements.

Origin and distribution of thiophenes and furans in gas discharges from active volcanoes and geothermal systems.

The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C(2)-C(20) species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C(4)H(8)O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.

Laceyella tengchongensis sp. nov., a thermophile isolated from soil of a volcano.

A thermophilic strain, designated YIM 10002(T), was isolated from a soil sample of Big Empty Volcano in Tengchong county, Yunnan province, south-west China, and a polyphasic approach was used to investigate its taxonomic position. Strain YIM 10002(T) formed endospores on both aerial and substrate mycelia. Whole-cell hydrolysates contained meso-diaminopimelic acid, ribose, xylose and glucose. The major fatty acids were iso-C(15 : 0) and anteiso-C(15 : 0). The predominant menaquinone was MK-9. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides, together with some unknown phospholipids. The G+C content of its genomic DNA was 48.6 mol%. All of these chemotaxonomic data together with morphological characters consistently assigned strain YIM 10002(T) to the genus Laceyella. 16S rRNA gene sequence analysis showed that strain YIM 10002(T) was most closely related to Laceyella sacchari KCTC 9790(T) and Laceyella putida KCTC 3666(T) (99.9 and 98.0 % 16S rRNA gene sequence similarity, respectively). However, strain YIM 10002(T) showed relatively low DNA-DNA relatedness (34.0 and 39.0 %, respectively) with the above strains. Therefore, strain YIM 10002(T) represents a novel species of the genus Laceyella, for which the name Laceyella tengchongensis sp. nov. is proposed. The type strain is YIM 10002(T) (=DSM 45262(T) =CCTCC AA 208050(T)).

Effects of SO2 on respiratory system of adult Miyakejima resident 2 years after returning to the island.

BACKGROUND: Mt. Oyama in Miyakejima Island erupted in June, 2000. All Miyake villagers were forced to evacuate from the island in September, 2000, due to continuous eruptions and emissions of unsafe amounts of volcanic gas, mainly SO2. From February, 2005, Miyake villagers returned to the island despite volcanic gas still being emitted. OBJECTIVES: This study examines the 2-yr changes in Miyake residents' respiratory systems from autumn 2004 to November 2006. METHODS: The study population was 823 Miyake adult residents who participated in the health check-up in 2006. Respiratory effects were evaluated by a questionnaire for respiratory symptoms and spirometry. SO2 has been continuously monitored at 7 sampling points of the inhabited area. The mean SO2 concentration from February 2005 to November 2006 was 0.031 ppm. The area was categorized into 4 areas by SO2 concentration, namely, areas L, H-1, H-2 and H-3, where average SO2 concentrations were 0.019, 0.026, 0.032, and 0.045 ppm, respectively. RESULTS: The study subjects showed no deterioration in lung function. Prevalence of cough and phlegm among all participants were significantly higher in 2006 than in 2004, and age-, sex- and smoking-adjusted odds ratios of cough and phlegm were 1.75 (95%CI 1.33-2.30) and 1.44 (1.12-1.87). Prevalence of chronic bronchitis-like symptoms among normosusceptive subjects in 2006 was 4.1% which was significantly higher than that of 2.1% in 2004 (p=0.035). Compared to area L, the frequencies of phlegm and irritation of the nose were significantly increased in areas H-2 and H-3. CONCLUSION: SO2 exposure-related respiratory symptoms were observed in adult Miyakejima residents after returning to the island.