selenium in volcanic environments a review abstract selenium is a chemical element with major environmental implications due to the extremely narrow range between essential and toxic concentrations volcanoes emit significant amounts of se which has an enormous impact on the se cycle and potentially human and animal health this paper presents a broad overview of the current state of knowledge of major aspects of volcanic derived se focussing on the processes in soils and aquifers volcanic soils formed when volcanic products weather rapidly display peculiar characteristics selenium contents can be relatively high 1 2 orders of magnitude higher compared to the worldwide average 0 4 mg kg but often with low mobility the soils can be impacted by local deposition of volcanic emissions which are enriched in se due to volatilization in the magma chamber it seems that the chemical fate of se in volcanic soils is controlled by sorption processes on poorly crystalline phases which presence depends on the parental materials and weathering these sorption processes also determine leaching to groundwaters some volcanic aquifers have se concentrations above the who guideline of 10 g l this might also be related to geothermal activity in spite of the well documented interest on se during the last decades a significant number of uncertainties exist on the behavior of this fascinating element a preliminary model of the se cycle around volcanoes can be constructed but the well known analytical problems associated with se determinations have produced a lack of reliable information on some processes involved in the chemical interaction between soils and water this review therefore also aims to identify the processes where new efforts are needed to produce good quality data to be compared and integrated in global models

magmatic processes revealed by textural and compositional trends in merapi dome lavas syn eruptive degassing of volcanoes may lead to syn eruptive crystallization of groundmass phases we have investigated this process using textural and compositional analysis of dome material from merapi volcano central java indonesia samples included dome lavas from the 1986 88 1992 93 1994 and 1995 effusive periods as well as pyroclastic material deposited by the november 1994 dome collapse with total crystallinities commonly in excess of 70 phenocrysts 1 microlites the liquids present in merapi andesites are highly evolved rhyolitic at the time of eruption feldspar microlites in dome rocks consist of plagioclase cores ab63an29or8 surrounded by alkali feldspar rims ab53an5or42 compositional pairs which are not in equilibrium a change in the phase relations of the ternary feldspar system caused by degassing best explains the observed transition in feldspar composition a small proportion of highly vesicular airfall tephra grains from the 1994 collapse have less evolved glass compositions than typical dome material and contain rimless plagioclase microlites suggesting that the 1994 collapse event incorporated less degassed partially liquid magma in addition to fully solidified dome rock as decompression drives volatile exsolution rates of degassing and resultant microlite crystallization may be governed by magma ascent rate microlite crystallinity is nearly identical among the 1995 dome samples an indication that similar microlite growth conditions ph2 o and temperature were achieved throughout this extrusive period however microlite number density varied by more than a factor of four in these samples and generally increased with distance from the vent low vent ward microlite number densities and greater microlite concentrations down flow probably reflect progressively decreasing rates of undercooling at the time of crystal nucleation during extrusion of the 1995 dome comparison between dome extrusion episodes indicates a correlation between lava effusion rate and microlite number density suggesting that extrusion slowed during 1995 crystal textures and compositions in the 1992 93 and 1994 domes share the range exhibited by the 1995 dome suggesting that transitions in crystallization conditions i e rates of undercooling determined by effusion rate are cyclic q 2000 elsevier science b v all rights reserved

a new method for sampling and analyzing volcanic sublimates application to merapi volcano java abstract a new method for the sampling of sublimates from high temperature volcanic gases has been used at merapi volcano java in 1978 the sublimates were collected on the inner walls of silica tubes introduced into fumarolic vents volcanic gases were allowed to move freely through the tubes and as they cooled a fraction of the volatile components condensed on the inner walls of the tubes along the temperature gradient the sublimates were then analyzed by a combination of light microscopy scanning electron microscopy electron microprobe and x ray diffraction six successive zones of different compositions and mineralogical associations have been identified along the covered range of temperatures 900 to around 400 c from the high to the low temperatures these zones are composed of 1 cristobalite magnetite hercynite 2 molybdenite 3 acmite 4 halite sylvite 5 sphalerite pyrite and 6 galena equilibrium calculations show that these crystalline phases are stable for ps 2 pc 1 and po 2 values typical of magma buffered gases that have not been contaminated by atmospheric oxygen the deposits observed in the tubes may be useful in aiding the understanding of the mechanisms acting during the cooling of the gaseous phase on its way to the surface and before its emission into the atmosphere

direct rate measurements of eruption plumes at augustine volcano a problem of scaling and uncontrolled variables the march april 1986 eruption of augustine volcano alaska provided an opportunity to directly measure the flux of gas aerosol and ash particles during explosive eruption most previous direct measurements of volcanic emission rates are on plumes from fuming volcanoes or on very small eruption clouds direct measurements during explosive activity are needed to understand the scale relationships between passive degassing or small eruption plumes and highly explosive events conditions on april 3 1986 were ideal high winds clear visibility moderate activity three measurements were made 1 an airborne correlation spectrometer cospec provided mass flux rates of so2 2 treated filter samples chemically characterized the plume and 3 a quartz crystal microcascade impactor provided particle size distribution atmospheric conditions on april 3 caused the development of a lee wave plume which allowed us to constrain a model of plume dispersion leading to a forecast map of concentrations of so2 at greater distances from the vent on april 3 1986 the emission rate of so2 at augustine was 24 000 t d one of the largest direct volcanic rate measurements yet recorded with a cospec the results coupled with analytical results from samples simultaneously collected on filters allow us to estimate hcl emissions at 10 000 t d and ash eruption rate at 1 5 106 t d based on other data this ash eruption rate is about 1 50 of the maximum rate during the march april activity filter samples show that the gas aerosol proportions for sulfur and chlorine are about 10 1 and 4 1 respectively by contrast measurements of augustine s plume together with ground based gas sampling in july 1986 when the volcano was in a posteruptive fuming state are 380 t d so2 and approximately 8000 t d hcl with no ash emission the observations of large cl releases at augustine support the cl abundance conclusions of johnston 1980 based on study of melt inclusions in the 1976 lavas the results reinforce the need for more measurements during eruptions and for better understanding of scaling of volcanic emissions of various eruptive components

field gas chromatograph analyses of gases from a glowing dome at merapi volcano java indonesia 1977 1978 1979 abstract a new field gas chromatograph fgc and conventional evacuated bottle eb techniques have been used to study high temperature 600 c volcanic gases from merapi volcano indonesia during 1977 1978 and 1979 the fgc design allows analysis of h2o co2 so2 h2s h2 cos ch4 co n2 ar and o2 in a manner that prevents loss of sulfur and water by condensation inhibits corrosion from reactions of gases with lead in tubes and minimizes atmospheric contamination the fgc analyses are highly superior to the eb data especially with respect to prevention of sulfur loss from reaction of so2 and h2s in addition to providing much improved h2s data the fgc system minimizes oxidation of h2 and co from contaminating atmospheric o2 because of the elimination of a lengthy time interval between collection and analysis thermodynamic calculations indicated small errors for h2 and ch4 in the 1978 analyses provided by the proto type fgc device a later model fgc provided excellent analyses that were shown by thermodynamic calculations to be nearly equilibrium mixtures requiring only minor corrections the merapi gases are h2o rich 88 95 containing small amounts of co2 3 5 to 7 5 so2 0 3 to 1 2 and h2s 0 3 to 1 2 they resemble excess volatiles rubey 1955 except for too high a sulfur content thermodynamic calculations based on the analyses indicate that the gases were once at temperatures of at least 915 c with o2 fugacities near quartz magnetite fayalite and that they have not been significantly diluted by disequilibrium admixture of meteoric water below these temperatures this conclusion takes on special importance because stable isotope studies allard 1980 1982 of merapi gases have shown that the water is meteoric and that much of the carbon and sulfur could be from sedimentary sources the merapi gases therefore may be magmatic even though they are not juvenile but recycled crustal volatiles

geochemistry of atmospheric aerosols generated from lava seawater interactions 1 trace elements were measured in the aerosol plume produced by lava seawater interactions along the shoreline of kilauea volcano hawaii plume concentrations were normalized relative to hawaiian basalt composition and showed a linear log log covariation with their emanation coefficient an indicator of element volatility normalized aerosol concentrations also consistently covaried with corresponding normalized concentrations in dilute fumarolic gas from kilauea volcano and fumarolic gas condensates from kudryavy and merapi volcanoes despite different mechanisms of element volatilization conservatively estimated regional ocean deposition rates of cu cd ni pb mn zn fe and p were 50 times background rates thus upper ocean volcanism may be an important source of both toxic and nutrient elements to the surrounding ocean it appears unlikely however that shallow ocean volcanism can exert a significant impact on the global ecosystem even during massive lava emplacements

the relationship between water masses and benthic ostracod assemblages in the western coral sea southwest pacific abstract the bathymetric distribution of 67 ostracod genera identified in 42 sediment samples water depth range 370 3776 m from the western coral sea is documented statistical analyses of this dataset support preliminary observations that the vertical distribution of the ostracod fauna is largely controlled by the three water masses present in the studied area four ostracod assemblages are recognised assemblage i consisting mainly of ostracods present in the deep water assemblage ii consisting of ubiquitous ostracods and ostracods mostly confined to the antarctic intermediate water and assemblages iii and iv with ostracods characteristic of the western south pacific central water temperature food supply and dissolved oxygen level are believed to be the most important factors influencing the ostracods bathymetric zonation the present work establishes the potential of ostracods for use in palaeoceanographic reconstruction in the western pacific ocean

magmatic gases in well fluids aid the mapping of the flow pattern in a geothermal system abstract gas composition and silica concentrations of well fluids are used in conjunction with pressure temperature and enthalpy data to obtain a model of the drilled part of the krafla geothermal field northeast iceland a magma chamber is located at 3 8 km depth under the field magmatic gases emanate from the chamber and travel via a channel reaching the surface at the hveragil eruptive fissure the composition of the gases is apparently modified on the way in that sulphur which presumably is in the form of sulphur dioxide to begin with is removed on the way and what remains is in the form of hydrogen sulphide at the end it is suggested that the major removal mechanism is the deposition of pyrite and pyrrhotite during the passage of the gases through the hydrothermal system the hydrothermal system is divided into a lower part whose temperature exceeds 300 c and whose fluids are to a varying extent affected by the magmatic gases and an upper part whose temperature is ca 200 c this upper part is a run off from the lower part but the magmatic effects have mostly disappeared there

distribution of metals between particulate and gaseous forms in a volcanic plume in order to gain information on the distribution of metals between particles and gaseous forms in the plume of kilauea volcano a filter designed to collect metals associated with particles was followed in series by two other collectors intended to trap metals present in gaseous atomic molecular or complexed form first an acid bubbler bath and then a cold trap of the six metals measured all of the in tl and bi and almost all of the cd pb and cu were found on the filter none of any of the metals was detected in the acid bubbler bath masses equivalent to 0 3 of the amount of cd on the filter 0 4 of the amount of pb and 9 3 of the cu were measured in the cold trap the results indicate that all or nearly all of the six metals were partitioned to the particulate portion of the physical mixture of gases and particles that constitutes a volcanic plume but that there may be systematic differences between chalcophile metals in the ways they are partitioned between particulate and gaseous phases in a cooled plume and possibly differences in the acidity or other chemical properties of the molecular phases

genesis of acid sulfate alteration and au cu ag mineralization at summitville colorado the summitville au cu ag deposit occurs within a porphyritic quartz latite primarily in a zone of vuggy silica alteration characterized by leaching of all major elements except silica and iron vuggy silica is best developed between an elevation of 3 700 and 3 500 m where it occurs in irregular pipes and lenticular pods up to 70 m wide and is enclosed by up to 30 m of intense quartz alunite alteration the vuggy silica zones diminish in size with decreasing elevation and rarely exceed a width of 2 m below an elevation of 3 400 m these deep vuggy silica zones are enclosed by quartz kaolinite alteration with little or no alunite sulfide mineralization occurs primarily within the vuggy silica the sulfide assemblage changes with decreasing elevation from covellite luzonite or native gold to chalcopyrite tennantite sulfides occur lining voids or in microveinlets and are accompanied by minor kaolinitc but not by alunite gold also occurs in a near surface barite goethite jarosite assemblage that crosscuts the vuggy silica consideration of alunite kaolinitc and pyrite stability relations and of aluminum speciation at 250 degrees c indicates that a ph of 2 or below and a log f sub o 2 of 31 or 1 at 250 degrees c were necessary to produce vuggy silica alteration the chalcopyrite tennantite mineralization occurring at depth in the vuggy silica zone is indicative of less oxidizing and less acidic conditions the covellite luzonite or gold assemblage requires conditions intermediate between those necessary for vuggy silica alteration and for deep sulfide mineralization barite gold mineralization is interpreted as a near surface assemblage produced under highly acidic oxidizing conditions these textural and geochemical relationships indicate that sulfide and gold mineralization postdate the formation of vuggy silica alteration in the deposit and are not directly related to the highly acidic solutions necessary for this early acid leaching event the change from extreme acid leaching to copper sulfide and precious metal deposition may represent a transition from a magmatic vapor dominated to a liquid dominated system leading to more reducing and less acidic conditions during sulfide deposition

volatilization transport and sublimation of metallic and non metallic elements in high temperature gases at merapi volcano indonesia abstract condensates silica tube sublimates and incrustations were sampled from 500 800 c fumaroles and lava samples were collected at merapi volcano indonesia in jan feb 1984 with respect to the magma merapi gases are enriched by factors greater than 105 in se re bi and cd 104 105 in au br in pb and w 103 104 in mo cl cs s sn and ag 102 103 in as zn f and rb and 1 102 in cu k na sb ni ga v fe mn and li the fumaroles are transporting more than 106 grams day g d of s cl and f 104 106 g d of al br zn fe k and mg 103 104 g d of pb as mo mn v w and sr and less than 103 g d of ni cu cr ga sb bi cd li co and u with decreasing temperature 800 500 c there were five sublimate zones found in silica tubes 1 cristobalite and magnetite first deposition of si fe and al 2 k ca sulfate acmite halite sylvite and pyrite maximum deposition of cl na k si s fe mo br al rb cs mn w p ca re ag au and co 3 aphthitalite k na sulfate sphalerite galena and cs k sulfate maximum deposition of zn bi cd se and in higher deposition of pb and sn 4 pb k chloride and na k fe sulfate maximum deposition of pb sn and cu and 5 zn cu and k pb sulfates maximum deposition of pb sn ti as and sb the incrustations surrounding the fumaroles are also chemically zoned bi cd pb w mo zn cu k na v fe and mn are concentrated most in or very close to the vent as expected with cooling atmospheric contamination and dispersion the highly volatile elements br cl as and sb are transported primarily away from high temperature vents ba si p al ca and cr are derived from wall rock reactions incomplete degassing of shallow magma at 915 c is the origin of most of the elements in the merapi volcanic gas although it is partly contaminated by particles or wall rock reactions the metals are transported predominantly as chloride species as the gas cools in the fumarolic environment it becomes saturated with sublimate phases that fractionate from the gas in the order of their equilibrium saturation temperatures devolatilization of a cooling batholith could transport enough acids and metals to a hydrothermal system to play a significant role in forming an ore deposit however sublimation from a high temperature high velocity carrier gas is not efficient enough to form a large ore deposit re se cd and bi could be used as supporting evidence for magmatic fluid transport in an ore deposit

gas composition of the january 1983 eruption of kilauea volcano hawaii abstract gas collections were made from a 900 c vent both by conventional evacuated bottle wet chemical techniques and by manual pumping of flowthrough bottles the complete analyses suggest an equilibrium assemblage quenched at 1 010 c about midway between fountain and vent temperatures i suggest that the very low c s ratio is due to degassing of co2 during storage of the magma in a shallow reservoir before eruption the two sampling techniques yielded analytical data in mutual agreement

crater lake and post eruption hydrothermal activity el chichon volcano mexico abstract explosive eruptions of volcan el chichon in chiapas mexico on march 28 and april 3 4 1982 removed 0 2 km3 of rock to form a 1 km wide 300 m deep summit crater by late april 1982 a lake had begun to form on the crater floor and by november 1982 it attained a maximum surface area of 1 4 105 m2 and a volume of 5 106 m3 accumulation of 4 5 m of rainfall between july and october 1982 largely formed the lake in january 1983 temperatures of fumaroles on the crater floor and lower crater walls ranged from 98 to 115 c by october 1983 the maximum temperature of fumarole emissions was 99 c in january 1983 fumarole gas emissions were greater than 99 vol h2o with traces of co2 so2 and h2s the water of the lake was a hot t 52 58 c acidic ph 0 5 dilute solution 34 046 mg l 1 dissolved solids cl s 20 5 sediment from the lake contains the same silicate minerals as the rocks of the 1982 pyroclastic deposits together with less than 1 of elemental sulfur the composition and temperature of the lake water is attributed to 1 solution of fumarole emissions 2 reaction of lake water with hot rocks beneath the lake level 3 sediments washed into the lake from the crater walls 4 hydrothermal fluids leaching sediments and formational waters in sedimentary rocks of the basement 5 evaporation and 6 precipitation

elongated prismatic magnetite crystals in alh84001 carbonate globules potential martian magnetofossils using transmission electron microscopy tem we have analyzed magnetite fe 3o 4 crystals acid extracted from carbonate globules in martian meteorite alh84001 we studied 594 magnetites from alh84001 and grouped them into three populations on the basis of morphology 389 were irregularly shaped 164 were elongated prisms and 41 were whisker like as a possible terrestrial analog for the alh84001 elongated prisms we compared these magnetites with those produced by the terrestrial magnetotactic bacteria strain mv 1 by tem again we examined 206 magnetites recovered from strain mv 1 cells natural darwinian selection in terrestrial magnetotactic bacteria appears to have resulted in the formation of intracellular magnetite crystals having the physical and chemical properties that optimize their magnetic moment in this study we describe six properties of magnetite produced by biologically controlled mechanisms e g magnetotactic bacteria properties that collectively are not observed in any known population of inorganic magnetites these criteria can be used to distinguish one of the modes of origin for magnetites from samples with complex or unknown histories of the alh84001 magnetites that we have examined the elongated prismatic magnetite particles 27 of the total are indistinguishable from the mv 1 magnetites in five of these six characteristics observed for biogenically controlled mineralization of magnetite crystals

volatility of se and te during subduction related distillation and the geochemistry of epithermal ores of the western united states subduction partial melting of mantle and magma generation and ultimately magma degassing can lead to the preferential mobilization of volatile elements and compounds research indicates that devolatilization reactions in a subducted slab can cause the overlying mantle to be enriched in volatile ore forming constituents water co2 sulfur metal loid s this process of mantle enrichment plays an important role in subsequent magma generation and initiation of ore genesis furthermore the relative volatility of metal loid s appears to play a role in the ultimate geochemistry of shallow epithermal epizonal hydrothermal ores in the western united states for example there is a general west to east geographic zonation of tertiary ores from se rich to te rich it is proposed that this geographic geochemical zonation is the direct result of the higher geochemical volatility of se as compared to te previously au ag te se hg as sb and tl have been referred to as the epithermal suite of elements it is suggested here that their geochemical cycles are linked by their similar volatile behavior through subduction partial melting in the mantle and subsequent magma degassing processes essentially specific tectonomagmatic events that affected the western united states e g oligocene eocene magmatism in the great basin and southern rocky mountains mid miocene magmatism associated with the inception of the yellowstone hotspot in the pacific northwest were distillation events that drove devolatilization of fertile mantle after the laramide shallow slab event furthermore the metal loid volatility behavior likely occurs in other regions affected by subduction and may play a fundamental role in the metal endowment of these regions

geochemical and geo electrical study of mud pools at the mutnovsky volcano south kamchatka russia behavior of elements structures of feeding channels and a model of origin this study presents data on the geochemical composition of boiling mud pools at the mutnovsky volcano the physicochemical characteristics of the pools and the concentrations of major minor and trace elements in pool solutions vary widely a comparison of the geochemical compositions of host rocks and solutions indicates that leaching from rocks is not the only source of chemicals in thermal solutions geophysical studies reveal the inner structure of thermal fields which reflect the shapes of the underground reservoirs and feed channels using geophysical methods electrical resistivity tomography and frequency domain investigations it was shown that the vertical structure and complex geochemical zonation of the feed channels leads to a high contrast in the compositions of the mud solutions these findings answer questions about the origin and composition of surface manifestations to elucidate the mechanisms of solution formation an attempt was made to describe the magmatic fluid evolution and the resulting mixing of waters by physical and mathematical models the model illustrates fluid migration from a magma chamber to the surface it is shown that the formation of brines corresponding to the mud pool composition is possible during secondary boiling

degassing of metals and metalloids from erupting seamount and mid ocean ridge volcanoes observations and predictions recently it has been reported that the element polonium degasses from mid ocean ridge and seamount volcanoes during eruptions published and new observations on other volatile metal and metalloid elements can also be interpreted as indicating significant degassing of magmatic vapors during submarine eruptions this process potentially plays an important role in the net transfer of chemical elements from erupting volcanoes to seawater in addition to that arising from sea floor hydrothermal systems in this paper a framework is constructed for predicting and assessing semiquantitatively the potential magnitude and chemical fingerprints in the water column of metal and metalloid degassing using 1 predictions from a summary of element volatilities during mafic subaerial volcanism worldwide and 2 limited data from submarine volcanic effusives the latter include analyses of polonium and trace metals in near volcano water masses sampled following a submarine eruption at loihi seamount hawaii 1000 m bsl in 1996 the element volatility predictions and observations show good agreement considering the limited dataset some of the highest volatility main group and transition element enrichments in seawater over loihi are predicted by the degassing mass transfer model i present when expanded to cover all submarine volcanic activity it is predicted that exit fluxes of these elements are up to 102 103 greater by degassing than by normal mor hydrothermalism in contrast mor exit fluxes of low volatility alkali and alkaline earth elements are likely 102 106 greater from hydrothermal inputs degassing inputs to the ocean are probably highly episodic occurring almost entirely during eruptions these are times of enhanced and abnormal hydrothermalism as well although major hydrothermal and degassing events may not be chemically recognizable in real water masses as wholly distinct entities it is nevertheless possible to predict to what extent each process flavors the effluents of the other degassing at mid ocean ridges may explain a variety of observations previously ascribed to complexities occurring during hydrothermal venting and or fluid ascent in the buoyant hydrothermal plumes above ridges

emissions of trace elements during the 2012 2013 effusive eruption of tolbachik volcano kamchatka enrichment factors partition coefficients and aerosol contribution abstract gases and aerosols from the 2012 13 effusive eruption of tolbachik basaltic volcano kamchatka were sampled in february and may 2013 from a lava tube window located 300 m from the eruptive crater temperature at the sampling point was 1060 1070 c the chemical and isotopic compositions of the sampled gases 92 4 h 2 o 3 5 co 2 2 3 so 2 on average d from 25 0 to 38 6 correspond to a typical volcanic arc gas without dilution by meteoric or hydrothermal water halogen contents in the gases 1 37 hcl 0 5 hf were higher than average arc values the total amount of analyzed metallic and metalloid trace elements in the gas exceeded 665 ppm six most abundant trace elements k 250 ppm na 220 ppm si 74 ppm br 48 ppm cu 21 ppm and fe 12 ppm accounted for 95 of the total content of trace elements in the gas the gases contained 24 ppb re 12 ppb ag 4 9 ppb au and 0 45 ppb pt refractory rock forming elements mg al ca and some other elements such as ba and th were transported mainly in the form of silicate microspheres and altered rock particles the concentrations of metals in the eruptive tolbachik gases are higher than the corresponding concentrations in high temperature fumaroles worldwide although the mutual ratios of the elements are approximately the same the gas magma partition coefficients of eleven elements exceed unity including the non metals f s cl br as se and te and the rare metals cd re tl and bi despite the relatively low concentrations of trace elements in the volcanic gases at the highest temperatures superficial magma degassing provides information on the sources and sinks of metals

volcanic emission of se te and as from kilauea volcano hawaii abstract the se te and as content of the eruptive gas and of sulfur sublimates from the current jan 1983 through mar 1985 east rift eruption of kilauea volcano hawaii have been determined these data in combination with previous data suggest that most of the se and te in eruptive plumes occur in the particulate fraction while most of the as is in the gas phase eruptive emissions to the atmosphere have been estimated at 10 metric tons each of se and as and 2 tons of te over the first 14 months of the eruption material balance calculations suggest 0 28 ppm se and 0 017 ppm te for the initial kilauean magma content of these elements only one third of the original se and te is lost from the magma by degassing

airborne aerosol measurements in the quiescent plume of mount st helens september 1980 atmospheric particulate matter and condensed volatile species were collected in the quiescent plume of mount st helens volcano in sept 1980 using air filter systems mounted aboard a nasa turbo prop p 3 aircraft concentrations of 27 elements were determined by instrumental neutron activation analysis and ion chromotagraphy the volatile elements cl br f zn w in s cd se sb hg as and au were enriched relative to bulk ash emitted during the earlier eruptions by factors of 50 to 20 000 particulate s concentrations were approx 3 mu g m sup 3 and accounted for 6 of the total plume sulfur gas phase hg concentrations were 2 5 to 16 ng m sup 3 fluxes of elements were estimated by normalizing elemental concentrations to the concurrently measured total sulfur flux emission rates vary from 3500 kg day for particulate cl to 3 kg day for au with substantial quantities of the enriched elements zn as hg sb se and cd also being released estimated global fluxes of these elements from volcanoes to the atmosphere are in reasonable agreement with other literature estimates