A radiometric analysis conducted between 1990 and 1991 identified the presence of radioactive isotopes Cs-134 and Cs-137 in the western Canary Islands. The work was a quick reconnaissance that pointed unmistakably to a single While the link to the Ukraine disaster from five years earlier was apparent, the broader context of previous nuclear weapons tests and later events could not account for these findings. Cesium isotopes have relatively short half-lives, which raised questions about how they arrived in the Canary Islands so far from their origin. This set the stage for a study produced by eight researchers from the universities of La Laguna and Malaga, who offered a possible explanation for the unusual results. The team included María López-Pérez, Francisco Hernández, Esperanza Liger, Elisa Gordo, José Carlos Fernández-Aldecoa, Francisco Javier Expósito, Juan Pedro Díaz, José Hernández-Armas and Pedro A. Salazar-Carballo.
heat is the answer
The key insight that began to resolve the mystery dating back to the 1990s is the transport of dust from the Sahara, a phenomenon with limited long-term records and data in some periods. This dust transport can carry radionuclides and alter the composition of airborne particles far from their source.
The study, with visuals referencing the Chernobyl occurrence, notes that the timing of radionuclide deposition aligns with known dust activity in the region. The researchers linked the presence of cesium to suspended dust that travels across Africa and the Atlantic, ultimately reaching the Canary Islands and creating hazy conditions at certain intervals.
The team concluded that unresolved questions about the path of Cs-134 first appeared in North Africa, where it became part of dust storms and was later redistributed by atmospheric currents. The analysis, carried out by scholars from the University of La Laguna in Tenerife, supports the idea that the material was carried aloft in dust bands and transported over thousands of kilometers before settling over the archipelago.
In this explanation, convection lifts dust to altitudes of six to seven kilometers over the Sahara and Sahel zones. When this dust migrates to the western edge of Africa, it rises above the cooler trade winds and forms a distinct elevated layer known as the Sahara Air Layer. From there, dust particles can travel toward the Canary Islands and contribute to periods of haze.
Further analysis looked at aerosol data collected over the past two decades in the Canary Islands, alongside historical records of dust columns from 1986 to 1991. The results indicate a steady input of mineral dust and Cesium-137 from North Africa, with a clear correlation to haze events during those times.
These findings offer a plausible mechanism explaining how small quantities of radioactive material released by the Chernobyl disaster could be detected as far away as the Canary Islands, aligning with known atmospheric transport patterns and dust processes documented in the region.
Reference work: the study is reported in a geochemical exploration journal, with attribution to the investigative team led by researchers from La Laguna and Malaga.
Additional context is provided by data sources and field observations cited within the study, which together support a narrative tying dust transport phenomena to the distribution of radionuclides across broad geographic distances. Researchers emphasize that these mechanisms are consistent with established models of long-range transport of mineral dust and trace radionuclides in the atmosphere.
Overall, the investigation highlights how natural atmospheric processes can connect distant events to observable signatures in far-flung locations, clarifying historical questions about how radionuclides appeared in areas far from their source and offering a framework for interpreting similar findings in the future.