In vitro biological effects of volcanic ash from Mount Sakurajima

Surface reactivity of Etna volcanic ash and evaluation of health risks

This work is a part of a research project conducted in order to characterize the volcanic ash from Mount Etna, focusing in particular on the surface reactivity of ashes and possible consequence for human health. In this framework, a sampling campaign began on 16 March 2013, taking advantage of the intense volcanic activity on Etna. The interaction between volcanic ash and human organism was simulated treating two classes of representative Etnean particles with ultrapure water (grainsize of 850 um) and Gamble's solution mimic lug fluids (grainsize <38 μm) with the aim to evaluate the risk due to gastric and respiratory exposure to volcanic particles. The leachates were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Ionic Chromatography (CI) in order to highlight possible dangerous elements released in water solutions according to USGS protocol. Analyses of Gamble's solution highlighted a release of elements smaller than in watery solutions and always below the thresholds established by the Italian law. On the contrary, analyses of watery solutions evidenced, for some elements (B, Cd, Ni and As), levels higher than permitted by Italian law. Considering the effects of these elements on human health, further investigations are necessary and currently carried out in order to better constrain the release process and the specific effects on human organism.

Biological Impact of Exposure to Extremely Fine-Grained Volcanic Ash

At the northwestern edge of South America is located Ecuador. This place is a classical example of an active continental margin with widespread active volcanism. Detailed studies about the impact of volcanic ash on human health are still lacking. Therefore, the disease of exposed populations is unknown. The objective of the present investigation was to assess the biological impact of Pichincha volcanic ash on cell culture and inflammation in murine lung tissues that will contribute to the understanding of the hazards. In this study, the in vivo phase was performed in mice C57BL/6 exposed to several doses of volcanic ash (0.5, 1, and 3.75 mg/100 g mouse body weight). The body weight and survival were controlled during seven days of treatment. The expression of inflammation markers NRLP 3, caspase-1, pro-IL-1, IL-1β, IL-6, IL-8, and h-HPRT was analyzed. The in vitro phase was performed in lung cancer cells A549, peritoneal macrophages, and McCoy cells exposing them to different concentrations of volcanic ash (80, 320, and 1280 μg/cm3) to determine the cytotoxicity and the production of reactive oxygen species. The ash initiated activation of the inflammasome complex NRLP 3 and the initiation of a proinflammatory activity in the murine lung tissue depending on the concentration of this agent. The viability of A549 and McCoy cell decreased with the length of exposure and increased with the concentration of volcanic ash. The activity in superoxide dismutase decreased by about 60%, leading to the formation of reactive oxygen species. These results associated with compounds contained in Pichincha volcanic ash are considered hazardous elements which induce inflammation leading to activate inflammasome NRLP, releasing reactive oxygen species, and producing changes in cell morphology and density, all of which are expression of cytotoxicity.

Montserrat volcanic ash induces lymph node granuloma and delayed lung inflammation

OBJECTIVES

A substantial amount of Montserrat volcanic ash, containing up to 24% of cristobalite (w/w), a fibrogenic crystalline silica, has been generated since the first documented eruption in 1995. The bioreactivity of the ash and its two major components: cristobalite and anorthite have been studied in vivo for a year following intratracheal instillation into rats.

METHODS

The rats (n=5) were instilled with a sterile vehicle solution (0.15 M NaCl) and/or three doses (1.0, 2.5 or 5.0 mg) of each of the dust, and were sacrificed at 13, 25 or 49 weeks post-instillation for quantitative biochemical and histopathological analyses in the lung and lymph nodes.

RESULTS

Cristobalite caused inflammation in the lung and granuloma in the hilar lymph nodes associated with significant size augmentation at 13 weeks post-instillation (P<0.05) and cristobalite (5.0 mg) induced fibrosis in the lung at 49 weeks post-exposure. However, the Montserrat volcanic ash caused inflammation in the lung at 49 weeks post-treatment without any fibrogenic response although the ash (5.0 mg) triggered significant lymph node enlargement without significant changes in the lung at 13 weeks post-treatment (P<0.05). Dose and time independent responses in the anorthite-exposed lung and lymph nodes suggest that a single instillation of 5.0 mg of poorly soluble mineral dust does not induce any change in the lung or lymph nodes.

CONCLUSION

The ash produces inflammatory reactions in lymph nodes at 13 weeks post-instillation in rats. These effects are seen much earlier than any inflammatory reaction in the lung. The onset of the lung inflammation is delayed until 49 weeks post-exposure. Despite the high cristobalite content of the ash, there is no evidence of any lung fibrogenic responses.

In the shadow of El Chichon: an overview of the medical impact of the 28 March to 4 April 1982 eruptions of the Mexican volcano

On 28 March 1982, El Chichon, a volcanic peak located in southern Mexico, began an eruptive phase of activity. Four major eruptions occurred within the next eight days, culminating in a cataclysmic eruption on 4 April. When the dust had settled, an estimated 200 million tons of ash blanketed more than 200 square kilometers of southern Mexico and neighboring Central American countries. Forty thousand villagers were left homeless and several thousand people may have lost their lives. Fifty thousand head of cattle were destroyed outright with many more succumbing to lack of water and pasture. Millions of hectares of crops were destroyed (Figure 1).

Health effects of volcanic ash: a repeat study

The Mount Sakurajima volcano in Kyushu, Japan, is proximal to a large residential area, and it emits an enormous amount of volcanic ash during frequent eruptions. In our previous study, we investigated, for the first time, respiratory effects of chronic exposure to volcanic ash. The study demonstrated a low prevalence of respiratory symptoms, even in the area of highest exposure; only a slight excess prevalence of symptoms appeared to be associated with exposure to volcanic ash. To confirm the findings of our previous study, the prevalence study of chronic respiratory symptoms for residents was repeated in Kanoya and Tashiro, which are located 25 and 50 km, respectively, from the crater of Mt. Sakurajima. The concentration of suspended particulate matter in Kanoya frequently exceeded the national environmental quality standards and, during summer and winter, was 2-3 times higher than that found in Tashiro. Women who were 30-59 y of age and who had resided in Kanoya or Tashiro for more than 3 y completed a modified ATS-DLD questionnaire. The prevalence of nonspecific respiratory disease was low, i.e., 6.5% in Kanoya and 6.2% in Tashiro; similar prevalences were found in women who had never smoked. When we restricted the analysis to individuals without a history of occupational exposure to dusts and who had no exposure to passive smoking, there was a slightly higher prevalence of nonspecific respiratory disease in Kanoya than Tashiro, but the difference was not significant. Eye symptoms were equally prevalent in the two areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary macrophages are attracted to inhaled particles through complement activation

Pulmonary macrophages play a central role in clearing inhaled particles from the lung. Previously, we showed that inhaled asbestos fibers activate complement-dependent chemotactic factors on alveolar surfaces to facilitate macrophage recruitment to sites of fiber deposition. In the studies presented here, we have tested a variety of inorganic particles for complement activation in vitro and correlated these data with results on particle-induced macrophage accumulation in vivo. We found that significant chemotactic activity was activated in rat serum and concentrated lavaged proteins by chrysotile and crocidolite asbestos, iron-coated chrysotile asbestos, fiberglass, and wollastonite fibers, as well as by carbonyl iron and zymosan particles. Ash from the Mt. St. Helens volcano did not induce chemotactic activity in either the serum or lavaged proteins. Rats were exposed to brief aerosols of each of the particles listed above (except zymosan). All the particle types studied were deposited primarily at first alveolar duct bifurcations. In addition, all of the particles, except Mt. St. Helens ash, induced at 48 h postexposure significant accumulations of macrophages at these sites. Time-course studies of carbonyl iron particle exposure demonstrated that iron induced a rapid macrophage response, but both particles and phagocytic macrophages were cleared from alveolar surfaces within 8 days after exposure. The Mt. St. Helens ash induced no macrophage accumulation at any time postexposure. We conclude that particles with a wide variety of physical characteristics are capable of activating complement and consequently attracting macrophages, both in vitro and in vivo. We suggest that complement activation is a mechanism through which pulmonary macrophages can detect inhaled particles on alveolar surfaces.

Chronic pulmonary effects of volcanic ash: an epidemiologic study

The chronic pulmonary effects of exposure to volcanic ash were investigated by conducting a cross-sectional epidemiological study of 2,006 women between 30 and 59 yr of age who lived in three areas subjected to different levels of airborne ash. In the three areas prevalences of chronic bronchitis and other respiratory symptoms were so low that volcanic ash did not seem to be a major cause of respiratory disease. In the highly exposed area, however, 9.9% of the women experienced symptoms of one or more respiratory diseases, while 6.4% of the women in the medium- and 5.4% of the women in the low-exposure area had these symptoms. Prevalences of each disease and symptom increased as total suspended particulate level increased, suggestive of an association of mild respiratory symptoms with volcanic ash.