Scientists from the Joint Institute for Nuclear Research studied the elemental and radioisotopic composition of ash from the powerful eruption of Shiveluch volcano in 2023. The data obtained made it possible to assess the potential health hazards in areas affected by the ash fall. The results of the study are published in the Journal of Environmental Management.

Images from the scanning electron microscope (SEM) of Shiveluch volcanic ash obtained at various magnifications using SE (Secondary Electron) and BSE (Back-Scattered Electron) detectors in the same area

Located in Kamchatka, Shiveluch volcano is the northernmost active volcano on the peninsula. Known for its rich history of powerful eruptions, it is one of the largest and most active modern andesite volcanoes, which attracts close attention of scientists studying volcanic activity. According to research data, the average volume of erupted material is 36 million tons per year.

Studying the impact of volcanic emissions on public health is a key factor in ensuring the safety of people in areas prone to volcanic activity. The employees of the Laboratory of Neutron Physics and the Laboratory of Radiation Biology at JINR, together with colleagues from the Kamchatka branch of the Pacific Geographical Institute of the Far Eastern Branch of the Russian Academy of Sciences (Petropavlovsk-Kamchatsky, Russia), conducted a detailed analysis of the chemical composition of volcanic ash ejected by the Shiveluch volcano. The elemental composition of the ash was compared with data on emissions from other large volcanoes, such as St. Helens (USA), Eyjafjallajökull (Iceland), Sinabung (Indonesia), and Popocatepetl (Mexico), to identify the main similarities and differences in their composition. Scanning electron microscopy, inductively coupled plasma mass spectrometry (ICP-MS), and low-background gamma-ray spectrometry were used to analyse the samples’ chemical composition.

A comparative analysis of the elemental composition of the Shiveluch volcanic ash and data on emissions from other volcanoes yielded interesting results. The amount of the main-group elements in the ash of the Kamchatka volcano turned out to be comparable with that of St. Helens but exceeded the values typical for the Sinabung volcano. At the same time, the concentration of most trace elements in the Shiveluch ash was lower than in the ash of the Indonesian stratovolcano. Analysis of the amount of chromium, cobalt, nickel, zinc, niobium, and silver in the ash samples from the two volcanoes revealed significant differences in their chemical composition.

Volcanic ash consisting of these elements can pose a threat to the environment and human health. After an eruption, metals can be re-suspended into the atmosphere or deposited on soil and water, leading to contact with human body through inhalation, ingestion, and touch. To assess the potential health risks associated with exposure to volcanic ash from the Shiveluch volcano, scientists calculated the chronic daily intake (CDI), hazard quotient (HQ), and hazard index (HI) for the following elements: chromium, cobalt, copper, nickel, zinc, arsenic, antimony, and lead.

Energy dispersive x-ray spectroscopy (EDX) of Shiveluch volcanic ash

“The data we obtained indicates a more significant effect of metalls on children’s health compared to adults. The reason for this may be the peculiarity of children’s behaviour, expressed in frequent contact with the environment. For example, outdoor games involving direct contact with volcanic ash can lead to the absorption of metals through the digestive system, respiratory tract, or skin,” Head of the FLNP Neutron Activation Analysis and Applied Research Sector Inga Zinicovscaia commented on the results.

An analysis of the ways of exposure to metals contained in the ash revealed the predominance of the oral route of entry in both groups. The calculation of the chronic daily intake confirmed this trend, demonstrating the following sequence of intake of metals into the body: by ingestion > by dermal contact > by inhalation. The researchers found that in case of children, the elements from the ashes most often entered the body through mouth: 10,000 times more often than through respiratory organs, and 100 times more often than through skin.

The study determined that chromium, arsenic, and antimony have the highest hazard quotients, which indicates a significant health risk for those exposed to these elements. Their presence in the human body can contribute to the development of oncological diseases, all kinds of skin damage, reproductive system disorders, and chromosome damage.

Concentrations of three natural radionuclides were determined by low-background gamma-ray spectrometry: radium-226 (²²⁶Ra), potassium-40 (⁴⁰K) and thorium-232 (²³²Th). The results showed that their radioactivity was below the global maximum value set by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in 2008.

“Generally, anthropogenic radionuclide caesium-137 (¹³⁷Cs), which is associated with anthropogenic activity, is also present in the analysis of soils, sediments, or any other materials. We did not detect this radioisotope in the collected volcanic ash samples. This indicates that the ashes are exclusively of natural origin, and no anthropogenic activity that could affect the content of radionuclides in the ashes was recorded,” Inga Zinicovscaia said.

Analysis revealed the presence of 54 chemical elements and three natural radionuclides in the content of the Shiveluch volcano ash. The calculated toxicity indices for chemical contaminants in the two age groups for all three main ways of exposure turned out to be significantly lower than critical values, which indicates that there is no significant risk to human health associated with exposure to the studied metals.

Elemental maps of the Shiveluch volcanic ash obtained from an area of 750 × 750 microns (using the example of three elements)

Despite the fact that the study did not reveal a significant risk of cancer development, it is important to note the potential danger of exposure to small doses of arsenic, chromium, or antimony. Further studies are required to assess the risks more precisely and to identify the long-term impact of exposure to these and other elements on human health.

As part of the new research, the JINR specialists, together with colleagues from Kamchatka scientific organizations, plan to conduct biological monitoring of the atmospheric air in residential areas affected by the ash using mosses as biomonitors. In addition, the researchers will study the influence of volcanic ash on the food safety, in particular, on plants in the area affected by volcanic ash.