At present, the main technological stages of oil production related to drilling operations require the use of a wide variety of drilling mud, which has a complex, multicomponent chemical composition. The drilling mud used and the resulting drilling waste must be safe for human health and the environment. The toxicity and hazard of drilling mud at this point in time remain poorly understood scientific problems and require detailing and studying in toxicological terms. The real degree of hazard and toxicity of drilling mud can only be determined by an experimental method, since its composition, which changes depending on the nature of the technological process and its degree of depletion, is not constant, which can change the toxicological properties. In an experiment conducted on adult male rats, under conditions of a single intragastric injection of drilling mud, new data were obtained regarding the parameters of its toxicity and hazard. The use of a wide variety of methods for determining lethal doses of drilling mud, including the probit analysis method, made it possible not only to substantiate the mean lethal dose of drilling mud but also other parameters of toxicity and survival of animals in the experimental groups. Features of eating behavior and body weight dynamics and the nature of the behavioral reactions revealed by the number and duration of stands and frequency and duration of grooming also indicate the presence of dose-dependent effects.

During the COVID-19 pandemic, working in any medical organization is associated with the risk of coronavirus infection. This applies first and foremost to specialized medical organizations dealing with the treatment of patients infected with coronavirus. Medical workers experiencing increased psychological stress are at an increased risk of infection with the SARS-CoV-2 virus while providing medical care. Therefore, studying the psychological states of medical workers – doctors, nurses, orderlies - is of particular importance and relevance. Our research goal is to investigate the psychological responses of medical professionals amid the COVID-19 pandemic. The research focused on the Aktobe Medical Center (AMC), which hosts the regional pulmonology center for COVID-19 patients and the Regional Clinical Infectious Diseases Hospital (RCIDH). The study is a selective, single-stage cross-sectional analysis. To assess the psychological reactions of medical workers, standardized questionnaires are used, including the PSM-25, GAD-7, and MFI-20. Statistical analysis of the data is conducted using the STATISTICA 10.0 software package from StatSoft, Inc., USA. An analysis of the research results indicates that medical personnel, nurses, and administrative staff in medical organizations associated with the risk of coronavirus infection are susceptible to adverse psychophysiological disorders. The study revealed that stress levels, anxiety, and asthenia in doctors and nursing staff are significantly higher compared to those in nurses and administrative personnel. Medical workers at risk of COVID- 19 clearly require support measures, as the potential for occupational infection has been definitively established. Additionally, the psychological risk is largely influenced by the nature of their work and their direct contact with the population and patients infected with the coronavirus. Senior and mid-level medical workers at the forefront of combating coronavirus infection is at a high risk of experiencing psycho-emotional and psychophysiological health issues. Doctors and nurses have been found to exhibit high levels of physical and mental asthenia, anxiety, and moderate-to-high levels of stress. Evaluating potential risk factors for psychophysiological disorders among healthcare workers not only provides an objective assessment of their health status, but also aids in the effective and rational organization of their work.

The aim of this study was to evaluate the toxic effects of drilling fluid (DF) on the skin in a subacute experimental model. Sexually mature outbred rats of both sexes were used (8 males and 8 females per group), weighing 180–220 g. Dermal exposure was performed for 14 days with monitoring of general condition, behavior, and feed and water intake. Body weight, vertical rearing, and grooming behavior were recorded on days 1, 7, and 14. At the end of the experiment, animals were euthanized for biological sample collection. Peripheral blood parameters, including hemoglobin, erythrocytes, leukocytes, platelets, erythrocyte sedimentation rate (ESR), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT), and C-reactive protein (CRP), were analyzed. Morphohistological examination of the epidermis, dermis, hair follicles, liver, and kidneys was performed. The elemental composition of the drilling fluid and drill cuttings was determined using atomic absorption and emission spectroscopy. Experimental animals exhibited reduced mobility and decreased feed and water intake by day 7. Body weight initially declined and subsequently increased. Dermal exposure to DF resulted in a significant increase in leukocyte, neutrophil, and eosinophil counts and was associated with alterations in detoxification enzyme activity (ALT, AST, and LDH). Histopathological changes were observed in the skin, liver, and kidneys, indicating dermal-resorptive toxicity. The results demonstrate that drilling fluid possesses dermal-resorptive toxicity following cutaneous exposure, causing not only local skin alterations but also systemic disturbances involving the hematopoietic, immune, and detoxification systems. The combination of clinical-behavioral, hematological, biochemical, and morphological changes confirms the potential occupational hazard of dermal contact with drilling fluids and substantiates the need to consider this route of exposure in occupational risk assessment. The findings provide an experimental basis for improving sanitary and hygienic standards, developing preventive measures, and conducting further toxicological studies, including investigations of chronic exposure, dose–response relationships, and the contribution of individual drilling fluid components.

Drilling fluids (DF) and the resulting drill cuttings (DC), widely used in oil production, pose a serious threat to the environment and human health. The issue of toxicity and danger of drilling fluids and drill cuttings still remains poorly understood and controversial. In this paper, we evaluate the dose-dependent effects of drilling fluid in an acute experiment with scientific substantiation of lethal doses, general condition and behavioral reactions, indices of enzymatic activity of detoxifying systems and morphological picture of peripheral blood. The obtained factual material convincingly demonstrates that drilling fluid has an adverse effect on adult guinea pigs. Lethal doses of drilling fluid (LD16, LD50, LD84, LD100) for a single intragastric administration, as well as indices of potential danger of acute poisoning are scientifically substantiated; The time of death and survival of experimental animals were calculated, which was dose-dependent. It was proven that the drilling fluid in an acute experiment leads to significant changes in the general condition of the experimental animals, accompanied by a decrease in food intake and water consumption, disruption of behavioral reactions and an emotional component. The dose dependence of the toxic effect of the drilling fluid was also established by the indicators of the dynamics of body weight gain, the activity of cytolytic enzymes, as well as the picture of peripheral blood. The features of the general toxic effect of the drilling fluid that we identified, with its acute single effect, indicate the systemic nature of the toxicity and danger of the drilling fluid.

An experimental study was conducted to assess the toxicological properties of the drilling fluid, including its general toxic, local irritant, and dermal-resorptive effects. Clinical and behavioral parameters, food and water consumption, body weight dynamics, relative weights of internal organs, and hematological and biochemical blood parameters were evaluated. The results obtained characterize the combined systemic and local toxic effects of the investigated drilling fluid.

Hearing loss is a major global health burden, and increasing evidence indicates that environmental and occupational exposure to neurotoxic metals may contribute to auditory dysfunction. This narrative review aimed to synthesize experimental evidence on metal-induced neuro-ototoxicity, with particular emphasis on morphological and functional alterations affecting peripheral and central components of the auditory system. A structured literature search was conducted in PubMed/MEDLINE, Web of Science, Scopus, and Google Scholar, focusing on animal studies investigating lead, mercury, cadmium, arsenic, and chromium exposure and auditory outcomes. Experimental evidence demonstrates that these metals can induce cochlear hair-cell injury, particularly involving outer hair cells and basal cochlear regions, as well as ribbon synapse loss, spiral ganglion dysfunction, and alterations of the stria vascularis. Central auditory effects include disrupted neural conduction, altered auditory brainstem responses, glial activation, synaptic dysfunction, and changes within the cochlear nucleus and inferior colliculus. Across metals, oxidative and nitrative stress, mitochondrial dysfunction, neuroinflammation, calcium dysregulation, and regulated cell death emerge as interconnected mechanisms. Notably, auditory synaptopathy and central auditory dysfunction may occur with limited overt hair-cell loss. These findings support a multisite model of metal-induced neuro-ototoxicity and highlight the importance of evaluating both peripheral and central auditory pathways in experimental toxicology and environmental health research.