Four regions of high natural radioactivity were selected to assess radionuclide levels in rocks and soils, ambient radiation doses, radon exhalation from the ground, and radon concentrations in the air. The regions have different geochemical characteristics and radioactivity levels, which modulate the radiation exposure of local populations. Combining radiometric data with data from regional health statistics on non-infectious diseases, a statistically significant positive correlation was found between radiation exposure and the incidence of cancer and birth defects. Although this is a preliminary and prospective study, the empirical evidence gathered in this paper indicated increased the incidence of some diseases in relationship with the natural radiation background. It is suggested that further research, including epidemiological studies and direct determination of radiation exposures in regions with a high natural radiation background, is needed and justified.

From the novel results of comprehensive geological–hydrobiogeochemical studies conducted on Olkhon Island (Lake Baikal), it follows that the phenomenon of geophagy among wild and domestic ungulates on the island is caused by the deficiency of light subgroup rare earth elements (LREE) in plant food and natural waters, while not denying the possible role of other factors. This deficiency reflects the low LREE specificity of the most abundant metamorphic terrigenous carbonate rocks on the island, as well as their overlying eluvium–deluvium and soils. The resulting specificity of the landscapes may be the cause of the LREE imbalance in the nervous and hormonal systems of the body, which makes the animals regularly and periodically consume clay (kaolinite) products from weathering, enriched with the necessary nutritional elements. The identified cause of geophagy on Olkhon Island is likely to extend to a significant part of geophagy cases among animals, including humans, especially in the equatorial zone of the Earth.

This study investigated the elemental composition of soils in Kyzylorda and Turkestan (southern Kazakhstan), an area rich in natural resources but facing potential environmental threats from industry and agriculture. The goal was to establish baseline geochemical values and assess soil contamination risks. Soil samples were collected from across the region and analyzed using ICP-MS and INAA techniques, providing a comprehensive profile of 72 elements. Statistical analysis revealed significant variations in elemental concentrations, with enrichments observed for specific elements when compared with reference values. Notably, both regions shared a core set of elements including rare earth elements (yttrium series: holmium, erbium, thulium), noble metals (gold, platinum, ruthenium, palladium), and tungsten. Enrichment patterns, however, provided distinct insights. Rare earth element enrichments likely reflect the region’s geology, while elevated radioactive elements necessitate further investigation to understand potential environmental and health risks. Enrichment of iron group elements might be linked to a combination of geological factors and anthropogenic activities like mining or industrial processes. A significantly higher number of elements exceeded background levels in Kyzylorda compared with Turkestan, suggesting greater element accumulation in Kyzylorda’s soil. This difference could be attributed to variations in regional geology or historical anthropogenic activities. The established geochemical baseline for 72 elements and the identified areas of potential contamination will inform land management practices, guide future environmental monitoring efforts, and ultimately contribute to the safeguarding of public health in southern Kazakhstan.

The analysis of published data on geophagy in humans, including manifestations of its variant known as “pica”, as well as information on geochemical endemics associated with geophagy and rare earth elements, together with our own research experience, allows us to conclude that geophagy in humans, as well as in animals, is primarily a natural, evolutionarily determined form of maintaining the necessary balance of rare earth elements in the neuroimmunoendocrine system. Disturbances in the composition and concentration of necessary rare earth elements (REE) in the structures of the most important protective and controlling system in the mammalian organism lead to disorders of mineral and general metabolism in the body and, as a result, to geochemical endemics. Geochemical endemics occur in landscapes with anomalous levels of biologically available REE forms, i.e., levels that differ significantly both towards deficiency and towards exceeding background levels. The imbalance in the metabolism of other chemical elements in the body seems to have a subordinate importance in the mechanism of occurrence of geochemical endemics in relation to REE.