STUDY OF THE INFLUENCE OF THE INSECTICIDE CARBOPHOS CONTAINING MALATION ON THE BIOCENOSIS OF SOIL AND WATER

Abstract

Background The article shows the influence of the insecticide Karbofos, the active ingredient of which is malathion, on soil and water biota. Various test organisms were used to determine the toxicity of the insecticide. Karbofos is used in the country's agriculture in the fight against various pests. Aims and Objectives The purpose of this work is to study the effect of the pesticide karbofos on soil and water biota: - determination of the toxic effect of the drug on seedlings of tomato seeds ( Solanum lycopersicum) , cucumber ( Cucumis sativus ) and wheat ( Triticum ); - study of the impact on the simplest aquatic organisms ciliates-shoes ( Paramecium сaudatum ); - study of the effect of the drug on earthworms ( Lumbricus terrestris L.) and microorganisms living in the soil; - study of the biodegradation of malathion using soil microorganisms. Methods The material for the experiments was the drug karbofos, in which the active substance is malathion, and the soil for the isolation of soil microorganisms capable of destroying the insecticide, selected in the ecologically clean territory of the Ufa region of the Republic of Bashkortostan. In the presented work, studies on phytotoxicity were carried out, the cultures of tomato ( Solanum lycopersicum ), cucumber ( Cucumis sativus ) and wheat ( Triticum ) were used as test objects; this preparation is often used in agriculture to treat these plants. Experiments to assess the toxicity of the insecticide to protozoan aquatic organisms were carried out on slipper ciliates ( Paramecium caudatum ). The research was carried out using BIOTESTER-2 device. Experiments on the effect of malophos on earthworms were carried out, taking into account their behavior, the condition of contact of earthworms ( Lumbricus sterrestris L .) with the drug was modeled. Determination of the number of microorganisms in the soil sample before and after exposure to insecticide at concentrations of 1 industrial concentration (IC), 2 IC and 5 IC was carried out by the method of «prints» in Petri dishes in beef-extract agar-agar, taken as a nutrient medium. Suspended soil samples were inoculated and cultivated for 2 to 5 days in a thermostat at a temperature of 28 °C. The microorganisms used malathion as a source of carbon and energy. The change in the destructive material was determined using a thin-layer chromatogram ( TLC ) using Silufol UV-254 plates, acetone as eluent, phosphoric-molybdic acid developer ( Rf = 0.5 ). Chromato-mass spectral analysis was performed on a Shimadzu GC-9A instrument. Results Experiments on the study of phytotoxicity showed that after treatment of seeds with the drug karbofos with different concentrations: IC, 2IC, 5IC and control (without the drug), the lengths of the aboveground and underground parts of plants that were etched differ from the lengths of the control -sample. The effect of the increasing dose is depressing in nature. Biotesting of the insecticide carbophos on infusoria-shoes showed that the toxicity index of the IC insecticide is 0.75 (group IV), therefore, the studied drug has a high degree of toxicity. The results of the analysis of the effect of the malathion-based insecticide on earthworms showed that the drug has a high toxic effect. In an experiment to establish the effect of an insecticide on soil bacteria, it was found that in the soil untreated with a toxicant, the microorganisms are dominated by Pseudomonas sp., Bacillus sp., Arthrobacter sp., Azotobacter sp., Flavobacterium sp. and Penicilium sp. The suppression and decrease in the number of microorganisms occurs already with IC. Contamination with 5 IC leads to the disappearance of Azotobacter sp., Arthrobacter sp. and Flavobacterium sp. from the soil microenvironment. The toxic effect of malathion is resisted by bacteria of the species Pseudomonas sp. and Bacillus. sp. Monitoring of the biodegradation of the studied drug, which was carried out using multinuclear 1H and 31P NMR spectroscopy, showed that the pesticide molecule practically does not undergo transformation even after 154 days.