Recent Volcanic Ash Research Articles

Rotation-age effects of subsoiling, fertilization, and weed control on radiata pine growth at sites with contrasting soil physical, nutrient, and water limitations

Although short- and medium-term responses to early silvicultural treatments have been documented, few studies show productivity gains or losses throughout a rotation across a range of soil types and resource availability. We evaluated the rotation length productivity responses of radiata pine to subsoiling, fertilization, and weed control in dry sand (DS), red clay (RC), and recent volcanic ash (RV) soils representing a gradient of physical, nutrient, and water limitations. Stands were planted in 2000 in a split-plot factorial design, with soil preparation (subsoiling vs. shovel planting) as the main plot and fertilization at planting (B only vs. NPKB) and weed control (none vs. 2-year banded application) as factorial randomized treatment plots within the main plots. Annual diameter at breast height, height, survival, and cumulative volume responses were measured. The rotation-age results for cumulative volume showed that early gains from weed control were maintained through at least 15 years of age. At rotation age, weed control increased the cumulative volume at the DS site (56 m3/ha, 20% gain), and the response over time was maintained at the RC site (28 m3/ha, 8% gain), whereas the volume was reduced at the RV site (-36 m3/ha, 7% loss). Fertilization resulted in the greatest response at the RC site (29 m3/ha, 8% gain); there were small responses at the DS site (5 m3/ha, 2% gain) and negative responses at the RV site (-18 m3/ha, 4% loss). Interestingly, subsoiling resulted in null or negative responses at all sites, and negative effects increased over time, with volume responses ranging from −4 m3/ha (1% loss) and −27 m3/ha (7% loss) at the DS and RC sites, respectively, to −116 m3/ha (21% loss) at the RV site. Carrying capacity was reached at mid-rotation at the RV site and resulted in negative treatment effects at rotation age, suggesting the need for thinning or a younger harvest age at this site. Given the negative or null effects of soil preparation, a better understanding is needed for how this silvicultural treatment is affected by soil type and soil strength.

Effect of elevation and slope orientation on pedogenesis of late Holocene volcanic ash on a tropical high mountain in central Mexico

The influence of climate on pedogenesis is elevation dependent, but little is known on the influence of slope orientation. This investigation focuses on the development of soils formed on Holocene (1100 and 5600 years old) volcanic ash deposits along an elevation gradient from 3000 to 4300 m a.s.l. on a high mountain in central Mexico. Soil profiles were analyzed on both N- and S-facing slopes at 3000, 3400, 3800, 4000 and 4300 m a.s.l. To determine the effect of climate (dependent on elevation and slope orientation) on pedogenetic processes, other factors such as age and type of parent material, landform position, and slope angle were kept constant. Soil temperature was recorded at 10 cm depth at each site for one year. Significant differences in temperature were found along the elevation gradient and between N-facing and S-facing slopes. Selective extractions of Fe, Al, and Si (using dithionite, oxalate, and pyrophosphate) indicate vitric properties on the 1100-year-old tephra (modern soil) throughout the elevation gradient, while the soil formed on the 5600-year-old tephra (buried by the 1100 year-old tephra) shows andic properties. The orientation of slopes has favored two evolutionary trajectories in the 1100-year-old soil: short-range-order minerals dominate on S-facing slopes, and organo-metallic complexes on N-facing slopes. The lower preservation of ash and pumice layers on S-facing slopes suggests that they have experienced geomorphic instability at centennial scales. The pedogenetic and stratigraphic differences observed between N- and S-facing slopes can be extrapolated to similar valleys and volcanic mountains.

Real‐Time Monitoring and Postprocessing of Thermal Infrared Video Images for Sampling and Mapping Groundwater Discharge

AbstractGroundwater discharge along channels can affect stream discharge, chemistry, and ecological communities. Although the spatial distribution of groundwater springs along wide rivers can be investigated by areal thermal infrared (TIR) remote sensing, this technique is difficult to apply to mapping at a high spatial resolution and under riparian tree canopies. We present a real‐time monitoring and postprocessing method of ground‐based TIR video for determining groundwater discharge sampling points and mapping the surface water temperature. We applied this method to mapping two headwater streams in Hokkaido, Japan, in the summer. The first site was a 1.3‐km‐long reach underlain by Pleistocene andesite lava. Almost all of the springs were colder and had a different chemistry compared to that of the stream water, which supports the usefulness of TIR monitoring for determining groundwater discharge zones. Video postprocessing showed that cold groundwater springs were spaced every ∼100 m, and their distribution did not follow the topography. At the second site, cold and warm springs were underlain by Holocene volcanic ash. The cold springs mainly seeped from hyporheic and riparian zones downstream, while warm springs were at the footslope. Some cold springs had much higher solute concentrations than the stream and warm springs, which suggests that the water temperature is useful for inferring sources of groundwater discharge. At this site, the video postprocessing could map not only the locations of the cold springs but also the spatial heterogeneity of the stream temperature associated with groundwater inputs.

Polygenic soils in the southern central Ecuadorian highlands as the result of long-lasting pedogenesis, geodynamic processes and climate change

In the high altitude (>3000 m asl) grasslands of northern Ecuador, the Páramo ecosystem, soils generally formed on recent volcanic ashes being <10,000 years old in the northern and central part of the cordilleras. With time these soils evolved in to non-allophanic Andisols with hydric properties such as evidenced in profiles from the Cajas massif located in the western central Cordillera. However soils at the Fierro Urcu massif and at the Oña plateau at the eastern Cordillera formed on a non pyroclastic indurated parent material. Compared to non-allophanic Andisols from the Cajas massif, they present similar morphological properties with a dark 50 cm thick carbon-rich (80–120 g kg−1) topsoil with a very low bulk density (<0.65 g cm−3) and high water retention. These top soils appear to have originated from fall-out, derived from close and still active volcanoes of Sangay and/or Tungurahua, both located in a distance of 200–250 km NNE of the Oña Massif, respectively. Geochemical determinations of trace and rare earth elements, however, confirm the lack of volcanic ash contribution in the Saraguro and Oña samples based on Eu/Eu* and Ce/Ce* anomalies relative to the lack of such anomalies in the Cajas samples. The Oña and Saraguro soils appear to be the result of a long-lasting double pedogenic process. The basement of the Saraguro soil is a Ferralsol with gibbsite and kaolinite and the Oña soil is a 5 m thick kaolinitic Ferralsol. The upper part of these profiles are the result of a major climatic change with increasing colder conditions, generating an increase in organic matter content and a very acidic environment leading to the instability of kaolinite and gibbsite, thereby liberating large amounts of free aluminium and iron oxides. The evolution of these very highly evolved Ferralsols into soils with Andic properties is proposed to be the result of rapid tectonic uplift calculated at a rate exceeding 0.6 mm/year in the region leading to a general decrease in temperature limiting carbon mineralization and favouring the formation of organo-metallic complexes. The soils studied here reveal compelling new evidence and information about the uplift of a part of the Ecuadorean Andes.

The thermal regime and mineralogical attributes of highland volcanic-ash soils from the Cotopaxi volcano, Ecuador: Absent permafrost and little pedogenesis

The high Andean volcanic zones constitute a unique environment, in which a sequence of lava flows and ash layers (tephra) form soils with distinct characteristics within a short distance. The objective of this study was to investigate soil genesis, mineralogy, and the possibility of permafrost occurrence along a representative toposequence at the periglacial zone in the northern slope of the Cotopaxi Volcano, Ecuador. Six soil profiles between 4000 and 4900 m above sea level were collected, to determine soil properties, mineralogy and petrology characteristics. Soil temperature and moisture were monitored from 2011 to 2015 at the highest zone (4900 m) at different soil layers. Overall, soils are layered with alternating ash and lapilli strata between little pedogenetically transformed soil layers with coarse texture, high stoniness and low clay contents associated with high levels of Na+, K+, and P. Andesitic-rhyolitic material, as well as volcanic scoriae, are the predominant material, and all soils show the presence of easily weathered primary minerals. Organic carbon contents decreased with increasing altitude, due to recent flows at higher parts creating an unstable slope, constraining the formation of A horizon. Landscape instability triggers colluvial processes, and cumulative buried A horizons are observed at the footslopes. Even at the highest altitude, no permafrost occurs at any depth in this active volcano, although little evidences of cryoturbation were observed. At this low latitude, higher solar energy on the soil surface and the current global warming, as well as recent volcanic activity, limit permafrost formation at the highest altitude. Higher temperatures, landscape stability and vegetation growth enhanced soil formation processes at the lower altitudes of the volcano toposequence, whereas the highest position have recent volcanic ash deposition and bare soils, with negligible soil formation.

Metallome deregulation and health-related impacts due to long-term exposure to recent volcanic ash deposits: New chemical and isotopic insights

Volcanic ash exposure can lead to significant health risks. Damage to the respiratory and pulmonary systems are the most evident toxic side effects although the causes of these symptoms remain unclear. Conversely, the effects on other organs remain largely under-explored, limiting our understanding of the long-term volcanic ash-related risk at the whole-body scale. The metallome i.e. metal concentrations and isotopic compositions within the body, is suspected to be affected by volcanic ash exposure, having thus the potential for capturing some specificities of ash toxicity. However, the means by and extent to which the metallome is affected at the entire body scale and how the consequent chemical and isotopic deregulations correlate with pathophysiological dysfunctions are currently poorly understood. Here, we adopt a transdisciplinary approach combining high precision chemical analyses (major and trace element concentrations) and CuZn isotope measurements in seven organs and two biological fluids of isogenic mice (C57BL/6) exposed to eruption products from La Soufrière de Guadeloupe (Eastern Carribean), in tandem with biological parameters including physiological and morphological data. Based on principal component analysis, we show that after one month of exposure to volcanic ash deposits, the mice metallome; originally organ-specific and isotopically-typified, is highly disrupted as shown for example by heavy metal accumulation in testis (e.g., Fe, Zn) and Cu, Zn isotopic divergence in liver, intestine and blood. These metallomic variations are correlated with early testicular defects and might reflect the warning signs of premature (entero)hepatic impairments that may seriously affect fertility and favor the emergence of liver diseases after prolonged exposure. Monitoring the temporal evolution of the Cu and Zn isotope compositions seems to be a promising technique to identify the main biological processes and vital functions that are vulnerable to environmental volcanogenic pollutants although this will require further validation on human subjects.

Role of abiotic factors in Nothofagus pumilio forest mortality: The sensitivity of ecotones

The world's forests are being affected by a changing climate. Recently, patches of dead trees have been found in forests of the Patagonian endemic species Nothofagus pumilio, which could not be related to insects or pathogenic fungi acting as primary agents. This study aimed to analyze environmental variables associated with N. pumilio mortality at a landscape scale. Dead patches were recorded from satellite image analysis and field trips throughout the distribution of N. pumilio forests in Chubut province (Argentina). The relation between forest mortality and environmental variables, including elevation, slope, aspect, recent volcanic ash deposits, precipitation, and temperature, was analyzed by contingency tables and chi-square analysis, and a risk model was developed using the Maximum Entropy (MaxEnt) algorithm. One hundred and seven dead patches were recorded only in the northern region of the study area (ca. −42.5°S to −44.5°S), where forests develop at higher elevations, slopes, precipitations, and temperatures than in the southern region. In the northern region, elevation, followed by precipitation, was the environmental variable most related to forest mortality. Nothofagus pumilio mortality was related to two ecotones: an altitudinal one, associated with middle-high mountainsides (1200 and 1400 m asl), and a longitudinal one, associated with intermediate values of mean annual precipitation within the west-east rainfall gradient. These results highlight the sensitivity of these transitional environments. According to the risk model based on abiotic features, more than 100,000 ha of forest (ca. 30%) are located under environmental variables favorable for decline and death. In the context of climate change and in the light of the results, abiotic factors seem to be the main predisposing factors of N. pumilio mortality.

Palaeoenvironmental use of silicophytoliths in soils and palaeosols associated with Holocene volcanic ash deposits in north-western Argentina

We compare the silicophytolith record of current soils and Holocene palaeosols from two sedimentary sequences in a region between the Chaco-Pampean Plain and the Puna (Tolombón section in Santa María Valley, and Tafí del Valle section in Tafí Valley), NW Argentina. These two geographic areas are separated by the Aconquija-Cumbres Calchaquíes ranges, a climatic barrier to the wet Atlantic winds. These sequences contain volcanic ash deposits recording two large eruptions occurred during Holocene in the Southern Puna in the Central Volcanic Zone of the Andes, from the Cueros de Purulla volcano (ca. 7820 BP) and the Cerro Blanco Volcanic Complex (ca. 4200 cal BP). These ash-fall deposits buried soils and preserved their silicophytolith record, allowing the use of this palaeoenvironmental proxy to clarify the vegetation prior these two volcanic events. The silicophytolith assemblages yield evidence for a desert shrubland when Tolombón palaeosol was formed, similar to the present-day environment in the Santa María Valley, with presence of C4 grasses (Chloridoideae and Panicoidae). Instead, the climate was cooler and wetter ca. 4200 cal BP than currently in the Tafí Valley, increasing over time aridity and abundance of C4 grasses (Chloridoidae, Panicoideae), and decreasing the quantity of C3 grasses (Pooideae). Prehistorical and historical land use also contributed to this change. The impact of these large volcanic ash-falls on vegetation did not translate in an abrupt change on phytodiversity. Results point out a stable arid environment during Holocene in the Santa María Valley whereas the Tafí Valley was more sensitive to environmental changes due to its location in the eastern slopes of Aconquija-Cumbres Calchaquíes ranges, more exposed to the wet Atlantic winds.

Characteristics and Classification of Soil Formed from Banda Recent Volcanic Ash on Various Topographic Positions

The Banda Islands consist of three main islands namely Banda Besar Island, Banda Naire Island, and Banda Api Island. Banda Api Mountain is an active volcano and based on history has erupted 20 times over the past 400 years. The eruption of volcanic ash has covered most of Banda Naire Island in the east and Banda Big Island in the east and south of Banda Api Mountain. This study aims to determine the characteristics and classification types of soil formed from parent material deposited in recent volcanic ash in different topographic positions. The method used was free survey method through toposequence approach by determining the profile point based on a straight line (transect) while soil classification refers to the Soil Taxonomy System. The results of the study showed that the profile of the soil at the position of the foothills on the island of Banda Naire and the Banda Besar morphologically had Andisols properties (Typic Hapludands), but in generally the physical and chemical characteristics of each soil profile did not match with the Andisols requirements so that they were classified into the Inceptisols (Vitrandic Eutrudepts and Vitrandic Dystrudepts) (in the slope and foothills), while at the top of the hill were classified as Entisols (Typic Udipsamments).

Multimethod Approach to the Study of Recent Volcanic Ashes from Tengger Volcanic Complex, Eastern Java, Indonesia

Volcanic ash is a volcanic product with a wide distribution that can be used as a geological marker. In volcanic regions such as Indonesia, the identification of the sources of volcanic ash and tuff layers from different volcanoes or eruptive events is a challenging task. In this study, samples of volcanic ash from the 2010 eruption of Bromo—a relatively young and active tuff cone volcano within the Sandsea caldera in the Tengger volcanic complex in East Java, Indonesia—along with two older tuff layers from the same caldera (Widodaren tuff: 1.8 kyr and Segarawedi tuff: 33 kyr) were subjected to magnetic measurements, geochemical analyses, and petrographic analyses. The aim is to attempt to use magnetic characters as a fingerprint for volcanic ash and tuff layers. The results show that the samples had variations in grain size and magnetic domain as indicated by the hysteresis parameters. These magnetic characters correlated with the results of geochemical and petrographic analyses, suggesting that magnetic properties may potentially be used as fingerprints to identify volcanic ashes and tuff layers.

Changes in the As solid speciation during weathering of volcanic ashes: A XAS study on Patagonian ashes and Chacopampean loess

X-ray absorption spectroscopy (XAS) was used to determine the oxidation state of As, local chemical coordination and the relative proportion of different As species in recent and ancient Andean volcanic ashes, as well as in Chaco Pampean loess. As K edge XANES analysis indicates that in loess sediments the dominant species is As(V) (i.e., >91%). Conversely, As(III) is dominant in all ash samples. In the Puyehue sample, only As(III) species were determined, while in both, the Chaitén and the ancient tephra samples, As(III) species accounts for 66% of the total As. The remaining 34% corresponds to As(−1) in the Chaitén sample and to As(V) in the weathered tephra. The proposed EXAFS models fit well with the experimental data, suggesting that in ancient and recent volcanic ashes, As(III) is likely related to As atoms present as impurities within the glass structure, forming hydroxide species bound to the Al-Si network. In addition, the identified As(−1) species is related to arsenian pyrite, while in the ancient volcanic ash, As(V) was likely a product of incipient weathering. In loess sediments, the identified As(V) species represents arsenate ions adsorbed onto Fe oxy(hydr)oxides, forming inner-sphere surface complexes, in a bidentate binuclear configuration.

Vegetation histories of Holocene volcanic ash soils in Japan and New Zealand Relationship between genesis of melanic volcanic ash soils and human impact

Vegetation histories of Holocene volcanic ash soils in Japan and New Zealand Relationship between genesis of melanic volcanic ash soils and human impact

Volcanic ash as a factor for radioecological conditions in Kamchatka part 1. The abundance and hypergene transformation of Th and U in recent volcanic ash

Concentrations of Th and U in fresh ash ejected by active volcanoes in Kamchatka are generally considerably below their Clarke values in their respective types of rock. The bulk concentrations of Th and U in andesitic and basaltic ashes do not show any obvious differences. The concentrations of their mobile forms decrease with increasing basicity of the ash. We revealed overall positive linear trends in the series of bulk concentrations for Th and U and a negative trend of Th/U in ashes that have been arranged over eruption year. Considerable quantities of mobile forms of radioactive elements fall during ashfalls in dissolved form or are sorbed by falling snow directly from the dispersive medium of volcanic aerosols. The original fractions of all of the mobile forms are 0.68–1.93% for Th and 1.16–3.21% for U. The bulk of these come to the Earth’s surface during eruptions when no snow cover was available. The quantities of mobile forms of Th and U were considerably decreased when ejected by winter-time eruptions during the time they resided in the snow.

Soil microorganisms and enzyme activity at different levels of organic matter stability

Soil biological activity has important implications for soil carbon (C) sequestration. However, very little is known about the environmental factors, particularly the effect of soil mineralogy on availability of C for soil microorganisms. In this study, we have investigated the influences of soil type (clay mineralogy)on C mineralization and its effects on biological activity at different levels of soil organic matter stability. Two soils an allophanic, derived from recent volcanic ash and a kaolinitic, resulting from metamorphic parent materials were physically fractioned in to light(LF, coarse sand 250-2000 µm), intermediate (IF, fine sand53-250 µm) and mineral (MF,silt and clay < 53 µm) fractions. Several biological and biochemical analyses at Ah horizons of mineral soil and physical fractions were conducted: soil respiration, enzymatic activities, carbohydratesand microbial biomass, amongst others soil variables. The results indicated that the bulk soiland physical fractions had a significant impact on cumulative C mineralizedafter 30 days of incubation and soil enzyme activities. More than 76% of total C-CO2 variation was explained by stepwise multiple regression analysis including factors such as soil enzymes (s-glucosidase, dehydrogenase and phosphatase) and inorganic P. Soil ATP extractionwas agood indicator of microbial activity, because of a positive and significant correlation among ATP and i) C-CO2 and ii) metabolic quotient (soil respiration rate divided by microbial biomass). We also found an inverse and significant relationship between Al pyrophosphate (Al bound to SOM) and the C-CO2 in volcanic soil, whereas the same correlation did not occur in kaolinitic soil. Our results confirmed a greater stabilization capacityof MF in allophanicthan in kaolinitic soils due to the amorphous minerals clay materials.

The impact of recent volcanic ash depositions on herbivores in Patagonia: a review

Volcanic tephra (ejected solids) result in varied impacts on ecosystems and livestock production. The recent Puyehue (2011) and Calbuco (2015) eruptions deposited large amounts of tephra in Chile and Argentina, affecting both livestock and wildlife in several ways. Impacts from Puyehue tephra on livestock were attributed initially solely to inanition, rumen blockage, eye problems, increased mechanical tooth wear; water consumption was considered without risk for humans and animals; and toxic effects were discarded. Subsequently, wildlife exhibited pronounced clinical signs of fluorosis and bone level exceeding 10 000 ppm of fluoride by 2014. Livestock including horses, cattle and sheep also had high levels of bone fluorine and clinical fluorosis. Tephra from Calbuco and Puyehue now overlap, containing on average 548 and 352 ppm fluoride, respectively. Dryness and eolic redeposition of tephra particularly east of the continental divide continues to re-expose domestic and wild ruminants. However, fluorosis and other related impacts like hypothyroidism, anaemia, and eosinophilia in ruminants also impact wool production. Although fluoride was discarded by others as a cause for the observed reduction in wool production, the specific effect of fluorosis on reducing wool production is well recognised, and occurs in sheep with less bone fluoride than reported from the Puyehue event. The rapid accumulation of fluoride in herbivores exposed to tephra from Puyehue coincides with reports that upon exposure to fluoride, sheep bone levels increased from 160 to 2300 ppm in only 3 months. The susceptibility of ruminants to fluorosis resides in their food processing: (1) intensive mastication and tephra size reduction, (2) thorough mixing of tephra with alkaline saliva during repeated rumination cycles, (3) water-soluble extraction in the rumen, and (4) extraction in the acidic abomasum. Lastly, the fluorosis may be further exacerbated by regional iodine and selenium deficiencies. Iodine deficiency may increase the incidence of dental fluorosis and the severity of damage, whereas selenium deficiency causes secondary iodine deficiency.

Strategic management of a family-owned airline: Analysing the absorptive capacity of Cimber Sterling Group A/S

The concept of absorptive capacity (ACAP) observing a firm's ability to value, assimilate and utilise new external knowledge is applied in this paper. This case study analysis focuses on the strategic management processes and competitiveness of the Cimber Sterling airline. The aim is to discover resources and capabilities that lead to competitive advantages within the aviation industry. From an ACAP perspective, Cimber Sterling Group A/S was analysed by interviewing selected owners, managers and employees of the airline. A comparison within the airline industry regarding external factors and the strategic management of other selected low-cost airlines is part of the ACAP concept. The analysis shows to what extent Cimber Sterling Group A/S, as a Danish family business, copes with increasing competition and critical situations, such as the recent volcanic ash cloud and the financial crisis. Identifying the potential and realised capacity of the strategic management of airlines was revealed as a source of strategic competitiveness. The ACAP was improved through stakeholder experience, strategic flexibility, networking capabilities and customer orientation, leading to a competitive advantage realisation in the low-cost airline market.

The influence of aeolian dust in non-allophanic Andosols on Yakushima Island

The oxygen isotope (δ18O) composition of quartz and the d(060) values of clay minerals were determined from four pedons of non-allophanic Andosols derived mainly from the Holocene volcanic ash on Yakushima Island. These soils contained considerable amounts of aerosol-sized (1–10 µm) and coarse (>53µm) quartz. The δ18O values for the aerosol-sized quartz ranged from 14.7‰ to 17.4‰, which was comparable to or slightly lower than known values for loess-derived Red and Yellow soils on Tanegashima Island located approximately 20 km east of Yakushima Island. The abundance and δ18O values of the aerosol-sized quartz indicated that non-allophanic Andosols on Yakushima Island were strongly influenced by aeolian dust. However, the presence of coarse quartz implied that granite-derived materials were also incorporated into non-allophanic Andosols. X-ray diffraction patterns for most clay minerals showed two broad peaks around 0.154 and 0.150 nm, respectively. The d(060) values confirmed that 2:1–2:1:1 clay minerals consisted of dioctahedral and trioctahedral clay minerals. Since aeolian dust contains little or no coarse quartz and trioctahedral clay minerals, the abundance of coarse quartz and trioctahedral minerals confirmed that the occurrence of non-allophanic Andosols on Yakushima was influenced by biotite-granite, in addition to aeolian dust.

Source and evolution of the clinopyroxenes in the Loire and Seine basins (France) based on grain morphology and color

Variation in the characteristics (color, morphology) of clinopyroxene grains (CPX) in alluvial deposits and other surficial formations in the Loire valley, the Gâtinais and the Beauce show that many are pristine and come directly from recent volcanic eruptions, whereas weathered grains, clearly reworked, come from erosion of Cenozoic and Pleistocene volcanic rocks of the French Massif Central. After deposition, the CPX have been increasingly altered by longer exposures. Weathering of brown CPX yields paler minerals which are greenish-brown, colourless or two-coloured. Similarly, the CPX found in the Seine basin are from recent volcanic ash or old Sologne deposits, and not from Loire alluvial deposits, so that a Pleistocene palaeo-Loire-Seine river is improbable.

Environmental geochemistry of recent volcanic ashes from the Southern Andes

Environmental contextExplosive volcanic eruptions may have significant environmental repercussions for many Earth system cycles, particularly the water cycle. We investigate the potential contribution to local geochemical fluxes through water of five historical eruptions that occurred over a 20-year period in the Southern Andes. In all five cases, the major potentially toxic trace elements were arsenic, copper, fluoride, molybdenum, nickel, lead and zinc. AbstractThe potential contribution to the local geochemical balance of five historical eruptions that occurred during the 20th Century has been investigated in the Southern Volcanic Zone (SVZ) of the Andean volcanic arc of South America (Lonquimay 1988, Hudson 1991, Copahue 2000, Llaima 2008, Chaitén 2008). These ashes were characterised by SEMEDX and XRD, and their potential released geochemical fluxes were examined using water and nitric acid batch leaching tests. Leachates were analysed by ICP-OES, ICP-MS and ISE. The major contents removed correspond to SO42– and Cl–. The potential toxic trace element (PTTE) content was highly variable among the ash samples following this order: Chaitén &gt; Copahue &gt; Hudson &gt; Llaima &gt; Lonquimay. The trace elements with significant load in water batch leaching tests include Fe &gt; F &gt; B &gt; P &gt; Zn &gt; As &gt; Mn &gt; Sr &gt; Ba &gt; Ti &gt; Cu &gt; Ni &gt; Li &gt; Rb &gt; Co &gt; Cr &gt; Cd &gt; Sb. Some of these elements (As, Cu, F, Mo, Ni, Pb and Zn) are included in the drinking water guidelines due to their potential toxicity and must be especially monitored in the environmental assessment of these ashfall deposits.

The European Regulatory Response to the Volcanic Ash Crisis between Fragmentation and Integration

More than twenty years after the EU eliminated its internal land borders, the Union still lacks an integrated airspace. This seems to be the most immediate regulatory lesson of the recent volcanic ash crisis. Yet more research is needed before establishing its net effects. In this brief report, I will provide a first-hand analysis of the regulatory answer developed across Europe in the aftermath of the eruption of the Icelandic volcano Eyjafjallajökull. While reconstructing the unfolding of the events and the procedures followed by the regulators, I will attempt to address some of the questions that I have repeatedly asked myself when stranded in Washington DC between 16 and 25 April 2010. Who did the assessment of the hazard posed by volcanic ash to jetliners? Who was competent to take risk management decisions, such as the controversial flight bans? Is it true that the safe level of volcanic ash was zero? How to explain the shift to a new safety threshold (of 2,000 mg/m3) only five days after the event? Did regulators overact? To what extent did they manage the perceived risk rather than the actual one? At a time when the impact of the volcanic ash cloud crisis is being closely scrutinised by both public authorities and the affected industries, it seems particularly timely to establish what happened during the worst aviation crisis in European history. This report was written one week after the event and relied on a limited number of sources available by 30 April 2010.