[Pollution hazard for water bodies at oil production].

In the paper there have been summarizes the concepts of the danger of the pollution ofwater bodies in oil production (the most dangerous are reagents used in the drilling, drilling waste, oil and petrochemicals, oil biodestructors. There was shown the danger of the spread of oil pollution. New indices, presenting a hazard during drilling and oil production have been substantiated The tasks aimed to the improvement of the standards and methods of the control of the water pollution by oil, as well as of the documents regulating the conditions of environmental protection during the drilling have been conceived.

[Scientific substantiation of hygienic criteria for sanitary-epidemiological assessment of chemical water disinfectants].

In the article there are considered the approaches to the hygienic assessment of efficacy and safety of chemical water disinfectants. On the basis of the own research of efficiency, with taking into account the reactivation of microorganisms, toxicity, impurity content, the processes of transformation of disinfectants, as well as the literature data there were developed the sanitary-epidemiological criteria for the assessment of the efficacy and safety of water disinfectants. These criteria include: the intensity of efficiency and time of exposure, the degree of universality of the action in relation to microorganisms, afteraction, lack of promoting of microorganisms tolerance, the ability to comply with the MPC after disinfection, the impact on the organoleptic properties of water, the probability of formation of hazardous transformation products in water, the presence of available and selective method for the determination in water, the possibility of neutralization, safety in use, transportation, storage.

[Regularities in the development of the toxic process in dependence on the stages of disorganization and adaptation].

At the based of the terms "disorganization" and "adaptation" there was studied the variation of the quantitative criterion of toxic effect--the threshold dose during the experiment with 222 chemicals with the oral toxicity. It is shown that the first manifestation of the effect may occur already in the 5th or 10th or 15th-20th day of intoxication. In the short-term and chronic experiments the dynamics of the toxic process on threshold effect level in time was established to be characterized by four types of models: the growth of the effect (reduction of the threshold doses)--14% of the substances, the absence of the changes in threshold doses--46% of the substances, the apparent weakening of the effect (increase of the threshold dose)--10% of the substances, undulating nature of the threshold doses changes (periodic rise and fall)--30% of the substances. The analysis of these differences with regard to the stage of disorganization and adaptation is carried out. The recommendations for clarifying the procedure of toxicological experiment depending on the dynamics of the toxic process at the threshold level are developed.

[Hygienic standardization of biotechnological strains in water reservoirs: current state and perspectives].

The question of need for standardization and validation of the complex methods to establish the maximum concentration limit (MCL) ofbiotechnological strains in the water of water bodies is under discussion. On the basis of the experimental studies it has been shown that a unified quantitative criterion for safety could not to be recommended for biotechnological strains and therefore requires the study of each strain in order to substantiate the safe level in water of water bodies. Proposed biosafety program should include the study of pathogenic properties in acute experiments and specific effects in subchronic experiments to study the influence of strains on the process of water purification and a risk assessment of transformation products of chemicals and the justification of the safety factor when establishing MCL t in terms of the toxic effect.

[Methods in the assessment of combined effect of substances].

Russian and foreign approaches to estimating the combined effect of substances are considered depending on the problems to be solved Data are given on the relationship of the type of combined effect to the mechanism of the toxic action of components and acting doses (concentrations). Various mathematical models for calculating the combined efect of mixtures are discussed There is evidence that it is necessary to study the combined effects of the mixtures of constant composition, which are used in water supply upon chronic exposure of the substances that are constituents of the mixtures. Based on their studies and the data available in the literature, the authors inferred that the nature of the combined effect of such mixtures should be investigated under the conditions suiting those of application, as well as when used at low concentrations.

[Substantiation of both safety indices for control over the use of chemicals for water disinfection and need to harmonize them with international requirements].

The domestic and also foreign indices applied for control over the safety of chemical disinfecting of water are considered. The data confirming need of extension of the list of legislatively approved indices are provided of water, efficiency and safety indicators, harmful impurity, transformation products. On the basis of the performed analysis of literature data and own investigations the following indices for inclusion in the processed. Sanitary standards and rules on drinking water are suggested: the total content of THM, the total content of haloacetic acids, the total maintenance of up to AHC index (adsorbed halogen-containing organic compounds) in water chlorination; chlorite- and chlorate ions in application of dioxide of chlorine; control over efficiency of water disinfection up to the steadiest microorganisms depending on an applied method. Introduction of settlement about necessity of control over the content of dangerous monomers and impurities in a commodity products in application of polymeric reagents and means of water disinfection is proved.

[Values of the micronucleus test on animal epithelial cells exposed to titanium dioxide].

The genetic safety of titanium dioxide (TD)-containing foods and cosmetic products has been little investigated. The study evaluated the mutagenic activity of TD in the micronucleus test with animal visceral mucosal epithelial cells. Two simethicone-coated anatase samples (mean size 160 and 33.2 nm) were inserted into the mouse stomach in doses of 40-200-1000 mg/kg seven times and applied as an ingredient of 10 and 25% cream (doses 250 and 625 mg/kg, respectively) to the hair-sheared rat skin once for 4 hours. Analysis of cytogenetic disorders (micronuclei, protrusions, and the atypical form of the nucleus) revealed no mutagenic properties of TD on the mucosal epithelium of the mouse and rat intestine, mouse prostomach, and rat uterine bladder. Enhanced mitotic activity was observed in all the study tissues after exposure of both samples to TD given in some or in all (in the rat urinary bladder mucosal epithelium) doses.

[Classification of substances to predict the order of magnitude of their safe water levels in terms of carcinogenic effect].

A classification has been developed to predict the safe water levels of chemical compounds in terms of their carcinogenic effect, by using as the base the LTD@10 value that is a lower 95% confidence limits for the lowest dose that statistically significantly causes a 10% increase in the incidence of cancer in laboratory animals continuously receiving a daily dose of the compound throughout their life, which is given in the CPDB internet resource, and the carcinogenicity classification adopted by the International Agency or Research on Cancer Based on an analysis ofthe maximum allowable concentration (MAC) of the standardized water substances in terms of their carcinogenic effect, the authors determined MA4 C ranges corresponding to different classes in accordance with the proposed classification. They predicted the orders of magnitude of MAC of the standardized water substances without taking into account their carcinogenic effect and those of four substances unstandardized in Russia.

[Dependence of carcinogenic properties of benzene derivatives on structure of their substituents adjusted for biotransformation].

An oxenoid model of the effect of cytochrome P450 and quantum chemical calculations were used to study a relationship of the carcinogenic activity of the benzene derivatives C6H5-X and C6H4-XY to the nature of the substituents X and Y For mono- and disubstituted benzenes, the methods based on the neglect of diatomic differential overlap was used to calculate the minimal values of AE for this compound, which is the minimum difference in the complete energies of the arenoxide intermediate OC6-H5-X or OC6H4-XY with one tetraedrically coordinated carbon atom in the benzene ring in reference to the initiar molecule of substituted benzene. The boundary value of the parameter deltaE min' which separated cancerogenic compounds from noncancerogenous ones was determined. A classification for nitrosubstituted benzenes was clarified using the parameter characterizing bioactivation via nitro group reduction to form phenylhydroxylamines and then nitrenic ions.

[Problems in harmonization of hygienic requirements for swimming pools with the international recommendations].

The paper considers the ways of harmonizing the hygienic requirements for the safe use of swimming pools. It proposes a procedure for substantiating the safe use of water disinfectants on the basis of real exposure factors, by bearing in mind their complex action. The proposed procedure is comparatively assessed with the methods and criteria laid down in foreign normative documents.

[The problem in the reactivation of microorganisms on evaluating the efficacy of water disinfectants].

The investigation deals with the topical problem of whether bacterial viability and properties may be restored after the achieved bacteriostatic effect of water disinfection, which reduces the reliability of the control and adequate assessment of its epidemic safety. The objective of the investigation was to study whether bacteria might be reactivated in the estimation of water disinfection with guanidine-containing agents as an alternative to chlorine. Experiments were carried out on the waters from model water reservoirs, by simulating water contamination with residential waste waters and on the natural water from the Moscow River, by reproducing the purification conditions: coagulation, filtration, disinfection with a binary mixture of polyhexamethyleneguanidine hydrochloride and quaternary ammonium compound. The experimental studies of the efficacy of the binary agent against indicator, opportunistic, and pathogenic bacteria indicated that the viability of bacterial cells might be reactivated and restored after water disinfection and cell multiplication upon further exposure. Microorganisms that had the greatest capacity for reactivation after use of the binary agent, as evidenced by the group values of the total number of saprophytes (microbial number) at 37 degrees C, coliform bacteria, and Pseudomonas aeruginosa, were identified. The findings show it necessary to consider reactivation processes in the evaluation of novel disinfectants, which requires a supplemented procedure for obligatorily estimating their exposure 24 hours after use of a reagent.

[Problem in the hygienic regulation and standardization of biotechnological strains in reservoir water].

The pattern of the negative effect of biotechnological strains belonging to different taxons was experimentally studied. The effect of the strains manifested as imbalance of immunocompetent cells, development of immediate and delayed hypersensitivity, and altered qualitative and quantitative characteristics of the autochtonic microflora of the intestine. The minimum acting (10(5) cells/l) and non-acting (10(4) cells/l) enteral exposure levels were determined for the bulk of the test strains. Analysis of the authors' findings and the data available in the literature made it possible to propose a study program on the hygienic regulation and standardization of industrial microorganisms and their based microbiological products in the reservoir water.

[Experimental study of proflavine acetate phototransformation processes].

Changes in proflavine acetate phototransformation processes upon exposure to visible-range irradiation were studied by high performance liquid chromatography. Proflavine acetate was offered as a photosensitizer during photodynamic water disinfection. Dye transformation products upon time-varying exposure to irradiation were identified. By using structure-activity relationships and information from toxicity databases, the authors evaluated the hazard of the identified products and identified the most hazardous ones.

[Effect of toxins of cyanobacteria of the Microcystis genus from the Shershnevo Reservoir on DNA, cell cycle, and apoptosis of bone marrow cells in CBA mice].

The effect of toxins of a Cyanobacterium sample of the Shershnevo Reservoir on DNA, which was presented by cyanobacteria of the Microcystis genera, on the bone marrow of male CBA mice (whose age was 3 months and weight 24 g) was evaluated. With intraperitoneal administration, LD50 and LD16 of this sample for male CBA mice were 48.4 and 42.1 mg/kg, respectively. Administration of Microcystis cyanobacterial sample from the Shershnevo Reservoir in doses of 1/10 of LD16 and 1/2 of LD16, and LD16 was found to cause a dose-dependent reduction in the number of bone marrow nucleated cells, a dose-dependent increase in the rate of cell apoptotic death, a reduction in the duration of a cell cycle (within the first 12 hours), which gave way to an increase in the duration of the cycle 24 hours after administration, a dose-dependent increase in the frequency of micronuclei in the murine bone marrow eryphrocytes, and a dose-dependent decrease in the polychromatophil/normochromatophil ratio in the murine bone marrow.

[General and specific aspects of the toxic properties of nanoparticles and other chemical substances in the context of classical toxicology].

The properties of nanoparticles versus chemical compounds in other physical forms were evaluated in the context of classical toxicology. A relationship of the toxicity of nanomaterials to the structure of molecules and the size of nanoparticles is discussed. Summing up the data available in the literature leads to the conclusion that there are general and specific aspects in the study of the toxicity of nanoparticles and chemical substances in other physical forms. There is a relationship of their toxicity to the dose and time of exposure for both nanoparticles and other chemical substances. It is noted that, as in classical toxicology, main conclusions on the toxicity and hazard of nanoparticles can be drawn only from traditional chronic toxicological experiments on the adequate route of their entry into the body.

[Hygienic standards of chemicals for water sterilization in the swimming pools].

The authors proposed a concept of making the hygienic standards for water disinfectants in the swimming pools, by substantiating their allowable residual concentrations (ARC), as well as criteria for evaluating the effectiveness and safety of swimming pool water disinfectants: a ratio of ARC to the optimum bactericidal concentration (if the ratio is less than 1; the agent is not recommended for use); a ratio of the maximum noneffective concentration of a local irritant action to the optimal bactericidal concentration of a disinfectant (if the ratio is < or =5; the agent is not permitted for use); a specific activity (agents that can cause allergenic and carcinogenic effects, as well as a mutagenic effect revealed on mammals or man are not permitted for use); the content of impurities in the disinfectant (when the agent is used in the dose equivalent to 3-5 optimal bactericidal concentrations; the water levels of impurities should be not more than 0.5 of the maximum permissible concentration. In accordance with the proposed procedure, ARC of BioPAH (polyhexamethyleneguanidine hydrochloride) has been estimated to be 5 mg/l. However, the agent may not be permitted for use in the swimming pools as it contains hazardous impurities.

[Comparative toxicity of photosensitizers in varying destruction].

The toxicity of the photosensitizers proflavine acetate (PA) versus methylene blue (MB) was evaluated during their varying destruction. Under the influence of visible light, a partial (25%) transformation of the photosensitizers was shown to be attended by their enhanced toxicity and 100% destruction of the parent substances caused a reduction in their hazard. PA and its phototransformation products mainly affect the antiperoxide protection system and the structural and functional states of the liver, kidney, and duodenum. The maximum noneffective dose is 0.002 mg/kg. The possibility of using PA for water disinfection depends on the ratio of safe and effective concentrations. A partial (25%) MB destruction products cause mutagenic effects; the permissible dose of the mutagen is 0.00025 mg/kg. MB is not recommended for disinfection of all types of waters.

[Evaluation of the sanitary-and-epidemiological safety of flocculating agents used for portable water purification].

Polyelectrolytes used in the practice of water supply to the population were comparatively hygienically studied, by using a complex of hazard indices and a new approach to sanitary-and-epidemiological evaluation of the safety of water-soluble polymers is substantiated. The anionic and cationic flocculating agents from different chemical classes, such as Superflok A-100, Fennopol A 321E, Fennopol K 221E, Praestol 2530 TR, VPK-402, Superflok C-577, Saipan, KF-91, Ecosol-401, a low molecular-weight sodium polyacrylate were tested as model compounds. Moreover, the information already available in the scientific literature on the toxicity of synthetic polyelectrolytes was analyzed. The generalized maximum permissible concentrations were substantiated for individual chemical classes of synthetic polyelectrolytes: polyacrylamides, polyamines, polydiallyldimethylammonium chloride.

[Comparative evaluation of health hazards associated with industrial chemicals and their derivates forming during water chlorination].

Many industrial chemicals found in waste waters are able to form organochlorine by-products during water disinfection. The transformation of seven model compounds, cyclohexene, n-butanol, diphenylmethane, acetophenone, aniline, 1-methylnaphthalene, and phenylxylylethane during a reaction with active chlorine was studied. Aqueous chlorine and sodium hypochlorite were used as chlorinating agents. The products of the reaction were analyzed by means of chromatomass-spectrometry. A schematic model of diphenylmethane transformation was proposed. Comparative evaluation of hazards associated with the model chemicals and their derivates confirmed that chlorination products can be more toxic and dangerous than the initial compounds, and may possess mutagenic and cancerigenic properties.

[Combined use of active chlorine and coagulants for drinking water purification and disinfection]. / Sovmestnoe primenenie aktivnogo khlora i koaguliantov dlia ochistki i obezzarazhivaniia pit'evoi vody.

The authors made an experimental study of the efficiency of water purification procedures based on the combined use of active chlorine and coagulants and hygienically evaluated the procedures. The study included the evaluation of water disinfection with various coagulants and active chlorine; the investigation of the processes of production of deleterious organic chlorine compounds; the assessment of the quality of water after its treatment. The coagulants representing aluminum polyoxychloride: RAX-10 (AQUA-AURATE 10) and RAX-18 (AQUA-AURATE 18), and aluminum sulfate, technically pure grade were tested. The treatment of river water with the coagulants RAX-10 and RAX-18, followed by precipitation, filtration, and chlorination under laboratory conditions, was shown to result in water disinfection to the levels complying with the requirements described in SanPiN 2.1.4.1074-01. RAX-18 showed the best disinfecting activity against total and heat-tolerant coliform bacteria, but also to the highly chlorine-resistant microrganisms--the spores of sulfite-reducing Clostridia, phages, and viruses. Since the coagulants have an increased sorptive capacity relative to humus and other organic substances, substitution of primary chlorination for coagulant treatment may induce a reduction in the risk of formation of oncogenically and mutagenically hazardous chlorinated hydrocarbons.