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.

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.