No abstract

Chemical methods for managing invasive plants in agriculture are dominant at present. Glyphosate-containing preparations are used as a desiccant and for drying of crops during pre-harvest period. Residual quantity of glyphosate founded in the grains of different crops was between 0.70 and 33.0 mg/kg. For example, the herbicide concentration in oats grown in the UK was about 0.9-14 mg/kg. As the result, herbicide is found in the environment, forage, food staff, animal tissues and human biomaterial. Chemical methods of analysis cannot conclude the toxic effects of herbicides on the environment, warm-blooded animals and humans. The purpose of the study was to examine the toxic effect of glyphosate on biochemical blood assays and organs of the laboratory rodents. The evaluation of influence of glyphosate was based on studies using 48 rodents. Chronic toxicity effects were determined by feeding rodents with grains containing 7, 14, 28 mg/kg of glyphosate. The exposure time was more than 4 months. The criteria for toxicity were based on biochemical changes of blood cells and tissues of rodents. Significant deviations of laboratory rodents’ physiological standards of blood indicators were determined during the study. The results of laboratory researches demonstrate quantitative and qualitative changes of blood cells. Glyphosate intoxication in concentration of 7, 14, 28 mg/kg caused leukopenia, anemia, by reducing the number of leukocytes and erythrocytes. As it was intimated, the average reduction of number of leukocytes in blood by 30% and 66 % was founded in the group of rodents fed with grains containing 7 mg/kg of glyphosate after 4 and 6 months of the experiment; in the group of rodents fed with grains containing 14 mg/kg of glyphosate after 4 and 6 months of the experiment the average reduction reached 30% and 62 %; in the group of rodents fed with grains containing 28 mg/kg of glyphosate after 4 and 6 months of the experiment the average reduction reached 38 % and 73 %. The decrease of erythrocytes in blood of laboratory rodents demonstrates a greater dose-effect relationship in comparison with leukocytes. The average reduction of number of erythrocytes in blood by 23% and 28 % was founded in the group of rodents fed with grains containing 7 mg/kg of glyphosate after 4 and 6 months of the experiment; in the group of rodents fed with grains containing 14 mg/kg of glyphosate after 4 and 6 months of the experiment the average reduction reached 36% and 47%; in the group of rodents fed with grains containing 28 mg/kg of glyphosate after 4 and 6 months of the experiment the average reduction reached 43% and 59%. Qualitative changes in erythrocytes were determined by changes in size and shape of cells. Postmortem examination of laboratory rodents founded changes in the liver, small and large intestine. The hepatotoxicity of glyphosate was expressed by changes in liver size, consistency and color. Negative influence of herbicide on the gut walls of small and large intestine was also expressed by the changes of intestinal mucosa color, consistency. A group of rodents fed with grains containing 28 mg/kg of glyphosate faced more abnormal changes of gut walls of small and large intestine, being reflected by the appearance of splinter hemorrhages under the intestinal mucosa of small intestine. The study also determined the negative effects of glyphosate on mammalian reproductive function and the viability of the posterity of laboratory rodents. The results demonstrate that chronic toxicity of herbicides contributes to the deviation of hematological and biochemical indices of blood, negatively affects differentiative state of liver, gut walls.

Glyphosate is the most promising herbicide currently used throughout the world. Glyphosate-containing preparations are also used as a desiccant in the pre-harvest period. Repeated processing of agricultural plants during the growth period and immediately before harvesting contributes to the accumulation of the herbicide in residual amounts in crops. The article presents the results of chronic intoxication of laboratory mice. It has been shown that glyphosate in residual amounts of 7, 14, 28 mg/kg is capable of causing quantitative and qualitative changes in formed blood cells, inhibits the functions of the reproductive system of experimental animals, and promotes changes in the structure of parenchymal organs. Experimental data indicate chronic toxicity of glyphosate at low concentrations.