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Introducton. Due to the increasing volumes of toxic substances entering the environment, including genotoxicants, it becomes necessary to conduct studies to assess their impact on people living in areas with high levels of pollutants, as well as people working in hazardous conditions. Epidemiological studies, in which damage to hereditary structures in human cells is assessed, in peripheral blood lymphocytes and buccal epithelial cells mainly, are carried out to determine the real genetic risk. Materials and methods. Samples of buccal epithelium were used. The study involved 69 people: 28 in the control group and 41 in the group of persons who were in contact with pesticides. The cytomorphological analysis took into account the following indicators: cytogenetic, cell proliferation, early and late destruction of nuclei. Results. The frequency of occurrence of the cells with micronuclei and protrusions in persons who were in contact with pesticides during their professional activities was increased 2.2 times, the frequency of cells with atypical nuclei - 2.5 times (differences in cytogenetic parameters between the groups were statistically insignificant). Statistically significant changes in the proliferation indicator were revealed - the frequency of cells with two nuclei (1.6 times), as well as the destruction indicators - karyorrhexis (4.5 times more often in nonsmokers and 8.2 times more often in smokers who work with pesticides) and karyolysis (the frequency of cells with initial karyolysis was increased by 3.4 times and 3.2 times with complete karyolysis). The index of accumulation of damage disorders was shown to be 4 times higher. Conclusion. The obtained data indicate an increased risk of damage to the genetic apparatus of cells in persons whose professional activities are associated with testing and using pesticides.

In order to overcome resistance to individual pesticides and improve their effectiveness, formulations containing two or more active substances are constantly being developed and put on the market over recent years. Mixtures of residual amounts of pesticides can be present in water and food and enter the human and animal bodies. However, the combined effect of pesticides on living organisms, including genetic structures in cells, has not been studied enough and it is not yet possible to predict the genotoxic effects of their mixtures based on available data. The purpose of this review was to collect and summarize literature information on the genotoxicity of pesticide combinations obtained at different objects. The results of studies conducted in different countries of the world are discussed, examples of detected synergistic, additive and antagonistic effects are given, indicating the need for testing the genotoxicity of preparative forms of pesticides containing several active substances, as well as mixtures of jointly used pesticides in order to ensure the safe use of pesticides for public health.

Introduction. Evaluation of genotoxicity of the pesticide technical products is one of the mandatory requirements for their toxicological and hygienic assessment. The data about mutagenic property is ambiguous for some pesticides. This may be due to the use of various active ingredients of technical products of the pesticide for testing, as they may have different profiles of relevant impurities, some of which may be potentially genotoxic. Material and methods. A technical product of N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine was tested using the bacterial reverse mutation method with Salmonella typhimurium (Ames test) and the in vivo mammalian micronucleus analysis in mouse bone marrow erythrocytes. Results. Statistically significant dose-dependent mutagenic effects of the technical product of N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine were revealed for TA97 (+S9 / -S9); TA100 (+S9 / -S9); TA102 (+S9 / -S9) and TA98 (+S9 / -S9) strains. In all cases, the fold increase of the revertant numbers mediated by the tested substance compared with the concurrent negative control was > 2 except TA98 in the presence of S9. In the micronucleus test, the technical product did not induce a statistically significant increase in the frequency of the micronucleated polychromatophilic erythrocytes in CD-1 mouse bone marrow up to 2000 mg/kg bw. Conclusion. The data suggest all technical products of pesticides entering the market should be tested for the potential genotoxicity. In such a case it is necessary to use at least two methods on different test systems for obtaining reliable results.

Graphical abstract, Highlights • Imidacloprid, imazalil, tebuconazole were non-genotoxic separately. • The mixture of imidacloprid + imazalil + tebuconazole was negative in Ames test. • The mixture induced a statistically significant increase in MN-PCEs in bone marrow. • The effect observed in vivo is probably mediated by synergism of TGAIs., Genotoxicity of the mixture of generic pesticides imidacloprid + imazalil + tebuconazole in a ratio of 14.0/1.7/1.0 by weight was assessed using Ames test (Salmonella typhimurium) and micronucleus test in vivo on mammalian bone marrow erythrocytes (CD-1 mice) supporting the data creation for the Real Life Risk Simulation (RLRS) approach. This pesticides’ combination is used in the commercial formulation for seed treatment in advance of or immediately before sowing. Tested pesticides’ technical grade active ingredients (TGAIs) showed no evidence of genotoxicity upon separate treatments. In combination, the three pesticides demonstrated negative results in the Ames test but induced a statistically significant, dose-depended increase in MN-PCEs in mice bone marrow at doses lower than those used separately. The observed effect may be mediated by the synergistic action of the tested TGAIs, their metabolites or impurities.

The results of genotoxicity assessment of 115 technical grade pesticide products (61 names) with the Ames test and mammalian erythrocyte micronucleus test in vivo are presented. In most cases, unidirectional results were found. However, some pesticides belonging to classes of neonicotinoids, derivatives of phenylurea, glycine and phenoxycarboxylic acids showed genotoxic effects only under in vivo conditions. All observed effects were statistically significant and dose-depended but were only slightly beyond the upper limit of the historical negative control. Pendimethalin (dinitroaniline pesticide) showed positive results only in Ames test. Furthermore, the limitations of Ames test related to the high cytotoxicity of pesticides against bacterial cells were shown (e.g. bipyridylium derivatives, chlorothalonils, dithiocarbamates, quinones, phenyl pyridinamines and sulphonylureas). But many pesticides possessing the highest cytotoxic activity against bacterial cells have shown low toxicity in vivo (MTD > 2000 mg/kg b.w.). On the other hand, all of the tested neonicotinoids, organophosphates, pyrethroids, phenoxycarboxylic acid derivatives were highly toxic to mice but non-cytotoxic against microbial cells. Triazole pesticides exerted toxicity to the target organ (bone marrow). Therefore, these findings suggest that genotoxicity assessment using at least two methods is needed for reliable evidence of the safe use of pesticides.

The article presents concise review of data obtained during last years at studying mutagenic and carcinogenic activity of pesticides in test-systems in vitro and in vivo Also, are covered the results of epidemiological surveys carried out in Russia and abroad related to discovery of association of effect of pesticides and development of oncological diseases in workers involved into agricultural manufacturing and in population of rural regions. The publications search was implemented using databases of Scopus, Medline, Google Scholar, RINTC. The issues are discussed concerning evaluation of mutagenic characteristics of effecting substances and preparative forms ofpesticides, application of short-term tests for evaluating carcinogenicity, possible synergy effects in case of combination of two and more effecting substances of various pesticide preparations.

Research on potential mutagenic pesticide activity is an important part of their toxicological and hygienic assessment. The present article provides international and Russian legal and normative documents, which regulate such investigations. There is presented a list of the principal Organization for Economic Cooperation and Development (OECD) protocols in the field of genetic toxicology which reflect protocols in force, newly adopted and canceled protocols along with the revised versions of existing documents. As an example, major changes of the research protocol for mutagenic properties of chemical compounds in mammalian erythrocyte micronucleus test in vivo are reviewed. The article also provides the minimal set of methods required for the evaluation of the pesticide-induced initial DNA damage, gene, chromosome and/or genome mutations. The article notes the need for the mutagenic assessment of generic pesticides to verify the equivalence of active ingredients and carry out further studies of the combined actions of pesticide mixtures/

Graphical abstract, Highlights • Triazole pesticides exert an inhibitory effect on erythropoiesis in mammal bone marrow. • The effects of triazole pesticides may depend on the type and arrangement of substituents in molecules. • At the lower acceptable level of PCEs/(PCEs + NCEs) (20%) suppression of erythropoiesis masks cytogenetic effects. • The MTDs of 79 different technical materials of pesticide active ingredients for CD-1 mice have been determined., Effects of technical materials of pesticide active ingredients, belonging to various chemical classes, on erythropoiesis in mouse bone marrow were studied as part of the research on the pesticide mutagenic activity in micronucleus test. The purpose of the present study was to estimate the toxic action of the test substances on the target organ and the validity of the results of the micronucleus assay under conditions of erythropoiesis suppression. It was demonstrated that intragastrically administrated triazole pesticides reached bone marrow (target organ where micronucleus induction was assessed) and exerted an inhibitory effect on erythropoiesis. The effects of triazole pesticides were enhanced in the following order: difenoconazole ≤ tebuconazole

The Ames test is widely used in the mutagenicity evaluation of new and existing chemicals as a part of a compound selection strategy, regulatory control, the equivalence assessment, carcinogenic potential measurement etc. Intensification of the chemical industry and synthesis of plenty of new molecules has led to the necessity of tests with a higher throughput capacity. The 6-well miniaturized bacterial reverse mutation test and the standard Ames test were compared using 14 technical grade active ingredients (TGAIs) of pesticides. With some exceptions, the responses obtained in the miniscreen Ames are similar to those seen in the standard method: 4 overall test outcomes were negative and 9 were positive in both test versions, but 1 discordant result between the miniscreen and standard version. Comparison of the standard and the miniscreen Ames test resulted in 98% of concordance across five strains and conditions (±S9). The overall judgment is that the miniscreen Ames test can be used to assess the mutagenicity of pesticide analogs. It has the advantage of decreasing the number of materials and animals (for S9) and keeping a high-test performance.

Introduction. Currently, a large number of pesticide analogues manufactured past the expiration date of the patent protection of the original active ingredients are imported in the Russian Federation. The toxicological-hygienic examinations based on numerous trials, including mutagenicity (genotoxicity) studies, is necessary to confirm their safety. Material and methods. The study of the genotoxic activity of three technical products of the pesticide active ingredient, a benzoylcyclohexane-1,3-dione derivative, produced in the various factories was carried out. research was performed using the bacterial reverse mutation method (Ames test) and the in vivo mouse bone marrow micronucleus test. Results. Statistically significant and dose-dependent genotoxic effects of the test samples were observed in the strains of Salmonella typhimurium of TA 97, TA 102, TA 100. However, the increase in the number of revertants in the experiment versus the negative control was less than two in all cases, with the exception of strain TA 97. Weak but biologically significant outcomes were found in TA 97 culture (the increase in the number of revertants in comparison to spontaneous level was ≥ 2. In the micronucleus test only two of the three samples produced a statistically significant increase in the incidence of micronucleated polychromatophilic erythrocytes. One of the samples induced the significant genotoxic effect only at the high dose (2000 mg/kg b.w.), and another one (with the lowest active substance content) at all dose levels. In both cases, a linear dose-effect dependence was found. The cytogenetic effects were low, at the level of the upper limit of the laboratory's historical negative control Conclusion. The obtained data indicate that the ability of the tested technical products of the benzoylcyclohexane-1,3-dione derivative to induce the gene and chromosomal damages increases with decreasing concentration of the active ingredient in technical products, probably due to the enhancement of the genotoxic impurity level. Thus, the technical products of analogue pesticides are not always equivalent to the original active substances in terms of their biological activity. That confirms the necessity for toxicological-hygienic testing, in particular genotoxicity assessments of all generic pesticides entering the market.