DESICCANTS (Latin desiccare to dry up) — the agricultural toxic chemicals applied to dehumidification of cultivated plants on a root for the purpose of acceleration of their maturing. Are toxic for hematothermal and the person. Special value has D.'s use for dehumidification of a cotton, seed fodder beans, a lupine. Desiccation of a cotton accelerates disclosure of boxes.
Drugs for desiccation, except active ingredient, contain surfactants and other additives.
As D. chemical connections of various classes are experienced: from inorganic compounds — chlorate and sodium arsenite, from organic matters — derivatives of ethers trichloroacetic to - you, amides methane-carbothiolic to - you, cacodylic to - you, aromatic and the heterocyclic compounds derivative of triazole and pyrazol. Connections of the same classes can be used in quality defoliants (see). As D.
pentachlorophenol, dipyridylphosphate, a raglan, gramokson were widely used.
Pentachlorophenol (synonym: penta, pentachlor, totalex). Pier. weight 266,33. Chemically pure pentachlorophenol — crystal substance with t ° pl 190 — 191 °, t°kip 310 °. It is dissolved in organic solvents. Receive chlorination of phenol in the presence of catalysts. The most effective form of technical drug — 20 — 25% solution of pentachlorophenol in metilnaftalanovy fraction or butyl acetic ether. Is volatile substance. Drug is highly toxic both at receipt inside, and at hit on skin.
At non-compliance with rules of work with drug at working increased fatigue, headaches, irritation of mucous membranes of a nose, an eye, and also face skin, hurried breathing, sharp temperature increase, excitement, increase in level of sugar in blood, sometimes a leukocytosis, an eosinophilia, sharply positive are observed oculocardic reflex (see). During the use of pentachlorophenol air pollution is observed at all stages of works — from opening of a container before spraying of plants. It is caused by a high volatility of drug. The highest concentration are defined in a zone of work of tractor operators and signallers. For desiccation two forms of pentachlorophenol can be used: mineral oil emulsion and oil solution. The last form is more toxic, especially at hit on the unprotected skin.
Dipiridilfosfat [synonym: bis dipyridylphosphate (0,0 dimethyl phosphate), N,N '-dimethyl-4,4, a dipiridiliya] — crystal substance with t ° pl 112 — 113 °. Let's well dissolve in water and it is insoluble in organic solvents. Technical drug contains 50% of active ingredient. Abroad apply in the form of sodium salt. Is drug of average toxicity, gets through skin. Irritates mucous membranes of eyes. Cumulative properties are expressed moderately. Causes decrease of the activity of cholinesterase and keeping of sulphhydryl groups in blood, breaks tissue respiration.
Raglan (synonym diquat). Active ingredient of drug — a diquat (1,1 - ethylene - 2,2-dipiridily) which represents white crystal powder with t ° pl 335 — 340 °. Let's easily dissolve in water. Technical drug represents the water solution containing 20% of a diquat (or 40% of salt of bromine). Action on mammals is based on formation of peroxides. Drug has high toxicity. Easily gets through skin. Irritates mucous membranes of eyes. It is capable to collect in an organism. It is widely used abroad (the USA, England, etc.), in the USSR because of high toxicity it is applied restrictedly.
Gramokson. Active ingredient — parakvat (N, N '-dimethyl-4,4-dipiridily) — white crystal matter with t ° pl apprx. 300 °. Let's well dissolve in water. Drug of a gramokson represents the water solution containing 20% of a parakvat. Is highly toxic, possesses the expressed skin and resorptive action. Nasal bleedings, an oliguria, increase in content of creatinine in urine and activity of transaminase of blood are possible. Can cause normokhromny anemia, decrease in oxidation-reduction processes. The peroxides which are formed in an organism cause damages of lungs.
In the USSR because of high toxicity and resistance in the environment for use it is not recommended.
Comparative toksikol, some D.' characteristic is presented in the table.
Dignity. - a gigabyte. working conditions during the work with D. are defined generally by the same factors, as during the work with page - x. toxic chemicals (see. Pesticides ).
First aid shall be given at emergence of the most insignificant symptoms of poisoning. The victim is deleted from a zone of works and exempted from the clothes contaminated and constraining breath. If drug got on skin, it is washed away a water jet or carefully deleted (a gauze, cotton wool, a piece of pure fabric), without smearing on the surface of skin, and then leather is processed solution of spirit of ammonia. At hit of drug the gastric lavage inside is necessary; to the victim allow to drink a suspension of active coal (1 — 2 table. l. on a half-glass of water). Symptomatic treatment.
Measures of prevention of poisoning of. Works with D. shall be mechanized. On the sites processed by D. storage of food stuffs, waters, fodder is not allowed. Work on these sites is allowed only after the expiration of the terms established for everyone to D. Rabotayushchiye with D. are provided with individual protection equipment.
Safety measures at D.'s use are regulated by «By health regulations on storage, transportation and use of pesticides (toxic chemicals) in agriculture».
Table. Comparative toxicity for hematothermal animal some desiccants and their maximum allowable concentration in air of a working zone
Bibliography: Bokarev K. S. Defoliants and desiccants of plants, M., 1965; Hygiene of use, toxicology of pesticides and clinic of poisonings, under the editorship of L. I. Medvedya, century 9, page 60, Kiev, 1971; Demidenko H. M. Materials for justification of maximum allowable concentration of pentachlorophenol in air, the Gigabyte. work and the prof. having got sick., No. 9, page 58, 1969; The M e l N and - to about in H. N. Himiya of pesticides, M., 1968; L. D Groans. Defoliants and desiccants, M., 1973.,
Yu. I. Kundiyev.