Eco-toxicological effects assessment: comparative characteristics of environmental conditions and status of vertebrate indicator species in the "Dnepr" launch vehicle accident zone.

Space rockets are regularly launched from the Baikonur Cosmodrome in Kazakhstan. The ecological impact of territories affected by the consequences of space rocket activities on the environment is a significant concern. On July 27, 2006, the Dnepr rocket was launched from the Baikonur Cosmodrome, resulting in an abnormal situation and its emergency fall. The rocket fuel components, heptyl, and amyl, led to decontamination and reclamation activities. However, the self-restoration of soil and vegetation cover is currently in the earliest stages. Consequently, an assessment of the remote consequences of the accidental fall of the Dnepr launch vehicle for environmental objects was conducted. The study involved eco-toxicological characterization of habitat conditions, assessment of species diversity, determination of key morphophenetic indicators, and the genetic status of indicator species as the main parameters. The results revealed an increased level of genotoxicity in soils at the accident site. While there were deviations from the norm in some morphophenetic and cytogenetic parameters in indicator animals, they were not critical for their existence in this territory. Possibly, at the physiological level, they exhibit a high enough adaptation potential and compensatory mechanism.

Ecological risk assessment and long-term environmental pollution caused by obsolete undisposed organochlorine pesticides.

Obsolete organochlorine pesticides (OSPs) are currently prohibited as persistent organic pollutants that contaminate the environment. If undisposed, they continue to pollute soil and water, to accumulate in the food chain and to harm plants, animals and the human body. The aim of the study was to assess water and soil pollution around the storehouses of undisposed, banned OSPs and their possible genotoxic effect. The storehouses in four villages near Almaty, Kazakhstan were investigated. Chemical analysis confirmed contamination of water and soil around storehouses with OSPs. The genotoxic effect of water and soil samples was evaluated using model objects: S.typhymurium, D.melanogaster, sheep lymphocytes cultures and human lymphocytes cultures. It was found that water and soil samples caused mutagenic effect in all model systems. They increased the frequency of revertants in Salmonella, the frequency of lethal mutations in Drosophila chromosomes, and the frequency of chromosome aberrations in cultures of human and sheep lymphocytes. Although a genotoxic effect was demonstrated for each of these models, various models showed different sensitivity to the effects of pesticides and they varied degree of response. The association between the total content of OCPs in soil and the level of mutations for different model systems was discovered.

Persons chronically exposed to low doses of ionizing radiation: A cytogenetic dosimetry study.

The dosimetry and control of exposure for individuals chronically exposed to ionizing radiation are important and complex issues. Assessment may be optimized by evaluating individual adaptation and radiosensitivity, but it is not possible for a single model to account for all relevant parameters. Our goal was to develop approaches for the calculation of doses for persons chronically exposed to ionizing radiation, taking their radiosensitivities into consideration. On the basis of ex vivo radiation of blood samples, dose-effect models were constructed for dose ranges 0.01-2.0 and 0.01-0.4 Gy, using different cytogenetic criteria. The frequencies of "dicentric chromosomes and rings" at low doses are too low to have predictive value. The different responses of subjects to radiation made it possible to categorize them according to their radiosensitivities and to generate separate dose-effect curves for radiosensitive, average, and radioresistant individuals, reducing the amount of error in retrospective dosimetry.

Cytome analysis (micronuclei and nuclear anomalies) in bioindication of environmental pollution in animals with nuclear erythrocytes.

Assessment of cytogenetic homeostasis of indicator animals is of great importance in ecological monitoring. The simplest method of its study is micronucleus analysis. Animals with nuclear erythrocytes are often used as indicator animals. In addition to the micronuclei usually recorded, a wide range of cytological nuclear and cellular abnormalities (cytomic analysis) is encountered when assessing the spontaneous level and under the influence of anthropogenic factors. Spontaneous frequency of cytogenetic disorders in 36 species of fish, amphibians, reptiles and birds was studied. Ecological monitoring of territories of Kazakhstan with different types of pollution (radiation, petrochemical, pesticide, heavy metals, due to rocket and space activities) was carried out with the help of separate species of animals. The results of the study include comparative descriptions, schematics and microphotographs clearly demonstrating a wide range of cytological anomalies of nuclear erythrocytes of animals of different classes. The greatest spectrum of nuclear anomalies in the studied animals was registered at petrochemical and pesticide contamination of territories. Depending on the tasks and climatic-geographical conditions, all investigated species can be used as bioindicators. Testudo horsfieldii is an exception for desert regions due to high spontaneous micronuclei level in this species. A review of the names of the main nuclear anomalies is carried out and variants of its ordering are proposed.

Trends in the cytogenetic and immunologic status of healthy persons; Kazakhstan, 2007-2022.

Environmental pollution can affect immune health and genome stability. We have studied the immunological and cytogenetic status of healthy urban (Almaty City, which has high levels of air pollution) and rural residents of southern Kazakhstan, over the past 15 years. Differences between the groups in plasma immunoglobulin levels and chromosomal aberration frequencies were noted. Over the 15-year study period, decreases of immunoglobulin levels and increases of chromosomal aberration frequencies were observed and correlated with place of residence and ecological status of the region of residence; both ecological deterioration and the coronavirus pandemic are likely to have had negative effects.

Chronic human exposure to ionizing radiation: Individual variability of chromosomal aberration frequencies and G0 radiosensitivities.

Bio-monitoring of human radiation exposure is based, as a rule, on a single analysis of chromosomal aberrations. Factors such as radiosensitivity, adaptation, and the stability of cytogenetic indices are not taken into account. We studied frequency of chromosome aberrations (FCA) and G0 chromosome radiosensitivity following in vitro γ-exposure, over a 2.5-year period, for 129 residents of the Dolon settlement, part of the extreme radiation risk zone, Semipalatinsk nuclear test site region, Kazakhstan. Radiosensitivity was evaluated on the basis of FCA and dose assessment by physical dosimetry. FCA was 3-fold higher in Dolon inhabitants as in the control group (p ≤ 0.01). The average coefficient of variability of spontaneous FCA was 31 %. In 20 % of the subjects, it was very high (50-70 %). Individual dose estimation in a single study in such individuals may lead to significant errors. Individual G0-chromosomal radiosensitivity showed less variation (18.7 %). Chronic low-dose irradiation was an adaptive factor to the damaging dose (1 Gy). Three methods of individual radiosensitivity assessment were considered, based on: G0-chromosomal radiosensitivity under additional in vitro γ-radiation; FCA and average dose per year; FCA and total dose received during years of residence in a radiocontaminated settlement, according to physical dosimetry. There is a significant difference in response (FCA) between radiosensitive and radioresistant individuals. This should be taken into account in individual dosimetry and risk assessment of radiation exposure.

The effects of DNA repair polymorphisms on chromosome aberrations in the population of Kazakhstan.

Purpose: To analyze the effects of DNA repair polymorphism and other factors on the frequency chromosome aberrations in an irradiated cohort of subjects living around the Semipalatinsk nuclear test site and non-exposed group of subjects from ecologically favorable zones of Kazakhstan.Materials and methods: Blood samples were collected in the rural areas of the East Kazakhstan district around the Semipalatinsk nuclear test site and ecologically favorable zones of Almaty region of Kazakhstan. Chromosome aberrations in the fresh and cryopreserved peripheral blood lymphocyte cultures were analyzed by Giemsa staining. Single nucleotide polymorphisms at eight DNA repair genes (XRCC1 rs1799782, XRCC1 rs25487, XRCC3 rs861539, ATM rs1801516, XPD rs1799793, XPD rs13181, APEX1 rs1130409, and hOGG1 rs1052133) were determined by PCR-RFLP method.Results: The age of donors and smoking significantly affected the frequency of chromosome aberrations among the irradiated and control subjects. In the irradiated and control cohorts, the frequency of chromosome aberrations was significantly increased in the heterozygous ATM rs1801516 (1853 Asp/Asn) individuals; for the rest of the loci no significant associations between polymorphism and the frequency of chromosome aberrations were detected.Conclusions: The age of donors, smoking, and the ATM rs1801516 polymorphism significantly affect the frequency of chromosome aberrations among individuals inhabiting contaminated area around the Semipalatinsk nuclear weapon test site, as well as among those inhabiting ecologically favorable zones of Kazakhstan.