A hypothesis of sudden body fluid vaporization in the 79 AD victims of Vesuvius

The casts of Pompeii: Post-depositional methodological insights

The casts of Pompeii bear witness to the people who died during the Vesuvius 79 AD eruption. However, studies on the cause of death of these victims have not been conclusive. A previous important step is the understanding of the post-depositional processes and the impact of the plaster in bones, two issues that have not been previously evaluated. Here we report on the anthropological and the first chemical data obtained from the study of six casts from Porta Nola area and one from Terme Suburbane. A non-invasive chemical analysis by portable X-ray fluorescence was employed for the first time on these casts of Pompeii to determine the elemental composition of the bones and the plaster. Elemental profiles were determined providing important data that cross-referenced with anthropological and stratigraphic results, are clearly helpful in the reconstruction of the perimortem and post-mortem events concerning the history of these individuals. The comparative analyses carried out on the bone casts and other collections from burned bones of the necropolis of Porta Nola in Pompeii and Rome Sepolcreto Ostiense, and buried bones from Valencia (Spain), reveal the extent of high temperature alteration and post-depositional plaster contamination. These factors make bioarchaeological analyses difficult but still allow us to support asphyxia as the likely cause of death.

A new hazard scenario at Vesuvius: deadly thermal impact of detached ash cloud surges in 79CE at Herculaneum

Diluted pyroclastic density currents are capable to cause huge devastation and mortality around volcanoes, and temperature is a crucial parameter in assessing their lethal power. Reflectance analysis on carbonized wood from ancient Herculaneum allowed a new reconstruction of the thermal events that affected buildings and humans during the 79CE Vesuvius eruption. Here we show that the first PDC entered the town was a short-lived, ash cloud surge, with temperatures of 555-495 °C, capable of causing instant death of people, while leaving only a few decimeters of ash on ground, which we interpret as detached from high concentration currents. The subsequent pyroclastic currents that progressively buried the town were mostly higher concentration PDCs at lower temperatures, between 465 and 390 and 350-315 °C. Charcoal proved to be the only proxy capable of recording multiple, ephemeral extreme thermal events, thus revealing for the first time the real thermal impact of the 79CE eruption. The lethal impact documented for diluted PDC produced during ancient and recent volcanic eruptions suggests that such hazard deserves greater consideration at Vesuvius and elsewhere, especially the underestimated hazard associated with hot detached ash cloud surges, which, though short lived, may expose buildings to severe heat damages and people to death.

Molecular signatures written in bone proteins of 79 AD victims from Herculaneum and Pompeii

An extensive proteomic analysis was performed on a set of 12 bones of human victims of the eruption that in AD 79 rapidly buried Pompeii and Herculaneum, allowing the detection of molecular signatures imprinted in the surviving protein components. Bone collagen survived the heat of the eruption, bearing a piece of individual biological history encoded in chemical modifications. Here we show that the human bone proteomes from Pompeii are more degraded than those from the inhabitants of Herculaneum, despite the latter were exposed to temperatures much higher than those experienced in Pompeii. The analysis of the specimens from Pompeii shows lower content of non-collagenous proteins, higher deamidation level and higher extent of collagen modification. In Pompeii, the slow decomposition of victims' soft tissues in the natural dry-wet hydrogeological soil cycles damaged their bone proteome more than what was experienced at Herculaneum by the rapid vanishing of body tissues from intense heat, under the environmental condition of a permanent waterlogged burial context. Results herein presented are the first proteomic analyses of bones exposed to eruptive conditions, but also delivered encouraging results for potential biomarkers that might also impact future development of forensic bone proteomics.

Transmission of Zoonotic Diseases in the Daily Life of Ancient Pompeii and Herculaneum (79 CE, Italy): A Review of Animal-Human-Environment Interactions through Biological, Historical and Archaeological Sources

There is no doubt that the cultural and urban environments contributed to the animal-human interaction in the daily life of the ancient Roman world. The singularity of the circumstances of the burial of Pompeii and Herculaneum, together with literary sources and the extraordinary state of preservation of the archaeological and biological material found, has provided researchers with an opportunity, unique in its kind, to reconstruct the life and ways of living of its inhabitants. This study illustrates the main drivers and mechanisms for the distribution and transmission of zoonotic diseases in these ancient Roman populations, such as (i) the large number and role that different animal species played in the ancient Roman world; (ii) the environmental conditions for the survival of parasites, pathogens and vectors; (iii) the great variety and intensity of commercial activities and occupations that presented certain risks of infections; (iv) the absence of adequate safety controls during processing, distribution and preservation of foodstuffs in unsuitable environments and some culinary habits; (v) the inadequate mechanisms of the disposal of human waste and the biotic contamination of watercourses and reservoirs; and finally (vi) the use of animals related to religious and cultural practices.

The impact of pyroclastic density currents duration on humans: the case of the AD 79 eruption of Vesuvius

Pyroclastic density currents are ground hugging gas-particle flows that originate from the collapse of an eruption column or lava dome. They move away from the volcano at high speed, causing devastation. The impact is generally associated with flow dynamic pressure and temperature. Little emphasis has yet been given to flow duration, although it is emerging that the survival of people engulfed in a current strongly depends on the exposure time. The AD 79 event of Somma-Vesuvius is used here to demonstrate the impact of pyroclastic density currents on humans during an historical eruption. At Herculaneum, at the foot of the volcano, the temperature and strength of the flow were so high that survival was impossible. At Pompeii, in the distal area, we use a new model indicating that the current had low strength and low temperature, which is confirmed by the absence of signs of trauma on corpses. Under such conditions, survival should have been possible if the current lasted a few minutes or less. Instead, our calculations demonstrate a flow duration of 17 min, long enough to make lethal the breathing of ash suspended in the current. We conclude that in distal areas where the mechanical and thermal effects of a pyroclastic density currents are diminished, flow duration is the key for survival.

Preservation of neurons in an AD 79 vitrified human brain

Detecting the ultrastructure of brain tissue in human archaeological remains is a rare event that can offer unique insights into the structure of the ancient central nervous system (CNS). Yet ancient brains reported in the literature show only poor preservation of neuronal structures. Using scanning electron microscopy (SEM) and advanced image processing tools, we describe the direct visualization of neuronal tissue in vitrified brain and spinal cord remains which we discovered in a male victim of the AD 79 eruption in Herculaneum. We show exceptionally well preserved ancient neurons from different regions of the human CNS at unprecedented resolution. This tissue typically consists of organic matter, as detected using energy-dispersive X-ray spectroscopy. By means of a self-developed neural image processing network, we also show specific details of the neuronal nanomorphology, like the typical myelin periodicity evidenced in the brain axons. The perfect state of preservation of these structures is due to the unique process of vitrification which occurred at Herculaneum. The discovery of proteins whose genes are expressed in the different region of the human adult brain further agree with the neuronal origin of the unusual archaeological find. The conversion of human tissue into glass is the result of sudden exposure to scorching volcanic ash and the concomitant rapid drop in temperature. The eruptive-induced process of natural vitrification, locking the cellular structure of the CNS, allowed us to study possibly the best known example in archaeology of extraordinarily well-preserved human neuronal tissue from the brain and spinal cord.

Dental fluorosis in the Vesuvius towns in AD 79: a multidisciplinary approach

Background: Endemic fluorosis induced by high concentrations of fluoride in groundwater and soils is a major health problem in several countries, particularly in volcanic areas.Aim: To evaluate the occurrence of dental fluorosis resulting from exposure to high levels of environmental fluoride in 79 AD Herculaneum and close Vesuvius towns.Subjects and methods: The occurrence of dental fluorosis from teeth of the Herculaneum victims of the 79 AD eruption and some individuals from Pompeii (14-37 AD) and Nocera Inferiore (Salerno, IV sec. AD) was detected by means of Particle Induced Gamma-ray Emission technique (PIGE).Results: A clinical and analytical scenario of dental fluorosis resulted from the extreme high fluorine tooth content detected in teeth from Herculaneum and the Vesuvius area inhabitants. The adoption of PIGE technique has proved to be particularly effective in showing moderate as well as milder forms of dental fluorosis, otherwise not clearly detectable by clinical and histological analysis.Conclusions: Morphological, histological and elemental analysis of teeth of the 79 AD Herculaneum population show that in this area fluorosis occurred since Roman times.