The negative consequences of the use of pesticides include. Consequences of the use of pesticides. Do you know that

Huge damage to the ecology of the region is caused by chemical pesticides (insecticides, fungicides, herbicides) and low-quality mineral fertilizers both in open and in closed ground. Moreover, only 1-2% of the drug used has a beneficial effect. The rest of it remains on the plant, inhibiting its development, reducing the period of vegetation and fruiting, or falling on the soil, killing the beneficial microflora, stopping natural process decay and fermentation of plant residues.

Another negative effect of pesticides is the destruction of insect pollinators. About 80% of all flowering plants are pollinated by insects: bees, bumblebees and others. beneficial insects, which make up only about 20% of all insect species.

Pesticides cause especially great harm when they are used in greenhouses, where pesticide treatments are carried out not 1-2 times until the ovary appears on plants (as required by the instructions), but up to 30 times during the growing season. And the saddest thing is that processing is carried out a few days before harvesting cucumbers, tomatoes, peppers and green crops. With such pest control, the grown product itself becomes harmful to human health, since the whole is saturated with the strongest poisons.

Many pesticides change nutritional value plants - in carrots there is no carotene (data from the Lenfs of the enterprise), in apples - enzymes and vitamins. A high content of nitrates in vegetable crops reduces the ability to store for a long time and harms the health of the soil. It is known that vegetables grown indoors with the use of pesticides are stored, even in the refrigerator, much worse than those grown in the garden without their use.

It has been proven that pesticides can even change the technical structure of plants, cause damage to plants, their sterility, morphoses of vegetative genetic organs. Pesticides can dramatically change the agrotechnical qualities of cultivated crops.

At the same time, the forms of harmful insects suppressed by pesticides in any agrocenosis are no more than a fraction of a percent of total number types. Therefore, when using pesticides, not only objects are affected, but also many other species, which are a deterrent and the destruction of which leads to an outbreak in the number of suppressed forms.

To this it should be added that almost all types of insects develop resistance (from Latin - counteraction, resistance) to the pesticides used, which forced the development and use of more and more toxic and expensive drugs. Characteristically, resistance occurs in all groups of pesticides, regardless of their chemical composition.

According to their function, herbicides can be divided into several groups. One of them includes substances used to sterilize the soil; they completely prevent the development of plants on it. This group includes sodium chloride and borax. Herbicides of the second group destroy plants selectively, without affecting the necessary ones. For example, 2,4-dichlorophenoxyacetic acid (2,4-D) kills dicotyledonous weeds and unwanted trees and shrubs, but does not harm grasses. The third group includes substances that destroy all plants, but do not sterilize the soil, so that plants can then grow on this soil. This is how, for example, kerosene acts, apparently the first substance used as a herbicide. The fourth group combines systemic herbicides; applied to the shoots, they move along vascular system plants down and destroy their roots. Another way to categorize herbicides is based on the timing of their application, eg before planting, before emergence, etc.

5.2. Other negative effects of pesticide use on crop production

Target objects, for the suppression of which pesticides are used, usually make up no more than a few fractions of a percent of the total number of species in any agrocenosis.

For example, the consequences of the use of DDT in gardens are known: the death of "harmful" insects was accompanied by an outbreak of reproduction spider mites that did no harm before fruit crops. When the caterpillars of the white butterfly (Pieridae) were destroyed with the help of DDT, many predatory arthropods were also destroyed along the way, as a result of which the population of the white butterfly was not only restored, but also increased.

Let's take a few more examples.

U.S. corn crop losses from insects prior to pesticide use in the 1940s were about 3.5%. However, with the introduction of maize monoculture crop losses increased to 12%, despite a thousandfold increase in pesticide use. In general, from 1945 to 1989 in the United States, the use of insecticides increased 10 times, and the loss of agriculture from suppressed insects ... increased from 7 to 13%!

The story of the fight against one of the species of grasshoppers that infect rice in Southeast Asia is also typical. Mass reproduction of this species in the 1970s, as a result of rice monoculture in Indonesia, led to a shortage of millions tons rice (Indonesia's losses exceeded $1.5 billion in the mid-1980s). After that, resistant varieties were bred and new pesticides were introduced. After some success in this fight, the grasshopper again became a dangerous "pest". The reason was that, along with the grasshopper pesticides destroyed more hundreds of species of other insects - natural enemies grasshopper .

UNEXPECTED TROUBLE

“If we take a critical look at the situation with agricultural pests around the world, it becomes clear that the use of pesticides only contributes to their spread. This applies to species such as rice grasshopper, cotton bollworm, whitefly, cabbage moth and a great many other pests that live on almost all types of vegetable, grain, cotton and plantation crops. Pesticides destroy the natural enemies of pests, which fight them more successfully than pesticides..

Jeff Waage, director of the International Institute for Biological Control.
Magazine "Our planet". 1997. V.8. No. 4. P.27.

Chemical technology has been replaced by knowledge technology- so characterize the next stage of the struggle, when chemicals protections were replaced by biological ones - breeding spiders, beetles, competing grasshoppers, dragonflies. Pesticide companies fought furiously to keep the chemical defenses alive, but Indonesia was heading for an environmental disaster.

A large-scale experiment was carried out at the initiative of FAO in 1986: 2,500 farmers used pesticides as usual (on average 4 treatments per growing season) and received an average rice harvest of 61 c/ha. Another group of 7,000 farmers used mainly biological protection(they averaged less than one chemical treatment per season) and received average yield 74 c/ha. As a result of the experiment , since 1987 , government subsidies for the use of 57 types of the most common pesticides have been discontinued in Indonesia .

In recent years, FAO has carried out such experiments with similar results in the Philippines, Malaysia, Thailand and several other countries.

The second example relates to the practice of controlling "weeds" in rice paddies. The use of propanid (stama F-34 - a herbicide of the 3,4-D group) in rice fields first aroused delight in rice-growing countries due to the highly effective suppression of "weeds" from the genus Barnyard grass ( Echinochloa) . However, the displacement of barnyard bushes turned out to be the reason for the clogging of rice fields with weed-field red-grain wild varieties of rice. The latter, moreover, serve as active carriers of dangerous fungal disease rice - blasts (to combat it, the toxic fungicide zineb is used). Unlike barnyard grass, red-grain weeds of rice can no longer be suppressed by any herbicides, since they belong to the same genus (and sometimes species) of plants as cultivated rice.

As for the rice itself, propanide reduced its height, slowed down the growth and development of the growth cone, the accumulation of dry matter, reduced the assimilation surface of the leaves, and lengthened the duration of the growing season, especially early-ripening varieties. Soon the use of propane was reduced everywhere.

A serious negative effect of pesticides on agriculture is the creation after their application favorable environment for mass reproduction of forms that were in small quantities before the use of pesticides .

One of the negative effects of the use of pesticides is related to their possible stimulating effect on suppressed objects . Thus, DDT and some other pesticides can accelerate the development and increase the frequency of generation change in suppressed species (for example, in the spider mite).

The same has been observed in some Colorado potato beetle control operations. Sublethal doses of DDT, dieldrin and thiophos are not reduced, but in some way that is still unclear increase egg production of the Colorado potato beetle - by 33-65%. Back in 1976, there was evidence that in a number of US states the use of carbofuran (furadan) increased population of the Colorado potato beetle. Chlorophos in certain doses also stimulates development of the Colorado potato beetle.

Some insecticides can change the age-sex structure of the population so that the remaining individuals begin to produce more offspring. For example, in the Colorado potato beetle, after an initial sharp decline in its numbers under the influence of pesticides, the number of eggs in surviving individuals increases dramatically. Thus, the pesticides themselves include mechanisms that contribute to the accelerated development of resistance (through the acceleration of natural selection).

Many examples show that the number of rodents reduced by rodenticides (zoocides) recovers faster than those reduced by natural factors. So, puberty of gray marmots ( Marmota baibacina) proceeds faster in populations treated with a chemical method. Here, the percentage of females participating in reproduction is higher in all age groups in the first 2 years after the use of rodenticides. In pesticide-treated populations, the growth rate of these rodents was in some cases higher.

A negative consequence of the use of pesticides is the need to use special means of crop protection from the undesirable effects of pesticides : adsorbents, antidotes for plants, microbiological detoxification agents, etc. This not only significantly increases the cost of agricultural production, but also, most importantly, increases the chemical load on agrocenoses.

One of the directions in Western agriculture is the development of resistance to the action of any herbicides in cultivated plants. This allows stronger doses of herbicides to be used to control unwanted vegetation without harming the main crop. It turned out, however, that, for example, making corn genetically resistant to the popular herbicide 2,4-D is associated with a more than threefold increase in the incidence of corn infestation by aphids and a number of other diseases. final The result of breeding herbicide-resistant plant varieties has always been the growing use of herbicides and fungicides, increased chemical load on the environment .

The same will no doubt happen to the widely advertised biotechnology approach. Here the direction of action goes along several paths.

First, they try to introduce a "resistance gene" to a particular pesticide or group of pesticides into the genome of the protected form. This makes the agricultural plant resistant to large amounts of pesticides, which should defeat enemies that have adapted to low doses. This approach cannot give long-term positive results. First, it is difficult (if not impossible) to increase resistance to not one, but several pesticides that are commonly used in practice in this way. Secondly, increasing the doses of pesticides used does not have a lasting effect, also because the suppressed "pests" and "weeds" always win and increase in the end, despite the use of high concentrations of pesticides (see Chapter 6).

DANGEROUS "SUCCESS" IN GENETIC ENGINEERING

“Monsanto, a chemistry and biotechnology giant (St. Louis, USA), has announced that it has recalled “small quantities” of genetically modified canola seeds that contain an unsuitable gene that was introduced into the seeds by mistake.

Canola is a crop grown for livestock feed and for making oil for human consumption. Canola oil is used in low fat cooking, pharmaceuticals, food additives, confectionery, margarine, personal care products, lubricants, soaps and detergents.

Introducing an unwanted gene into a commercial product is the kind of error that has been predicted for decades by opponents of genetic engineering. Its proponents replied that this could not happen, both because of the quality assurance of the industry itself, and because of the heavy regulation by governments.

The recall was initiated by Monsanto Canada. The recalled canola seeds were genetically engineered to resist the effects of glyphosate, Monsanto's herbicide sold under the brand name Roundup. The idea is to treat "Roundup compatible" crops with this herbicide so that weeds are killed and the modified crops remain intact. Monsanto declined to say how many "incorrect" canola seeds were recalled (allegedly the number was "small").

Canadian government officials say the recall was large. The publishers of the Canadian Food Newsletter reported that a total of 60,000 bags of two types of canola seeds (LG3315 and LG3295) were recalled because either one or both types of seeds contained the erroneous gene. The recalled amount is sufficient to sow between 600,000 and 750,000 acres of land. When Monsanto discovered its mistake, some seeds had already been sown.

In Canada, there are three levels of approval for genetically engineered crops: environmental (cultivability), livestock (livestock feeding), and human (human feeding). Two roundup-resistant canola crop genes (RT-73 and RT-200) have been approved, with only RT-73 approved for livestock and humans. However, the unapproved RT-200 gene ended up in seeds that now have to be recalled.

The presence of the unapproved canola gene in commercial product indicates that Monsanto's quality assurance program failed in this case and that Canada's biotechnology regulatory system is ineffective. In the US, it is even weaker.

Data recent history indicate that serious problems can arise when genetically modified foods are placed on the market without due diligence.

In 1989, a Japanese firm was trading in L-tryptophan, an amino acid produced by a genetically engineered bacterium. The final product unexpectedly contained traces of contaminants, causing between 5,000 and 10,000 people in the United States to become ill with the serious illness eosinophilia-myalgia syndrome (EMS).

Clearly, genetically engineered products need extensive testing before their effects can be understood. The idea that genes control only one characteristic of a bacterium, plant, or animal turns out to be wrong. Genes contain potential that can manifest itself in different ways depending on the environment in which the gene grows: a gene can develop in one way in one environment and in a completely different way in another. Testing in one environment cannot reveal what a gene will do when placed in another environment. This has been elegantly demonstrated by Craig Holdrege in Genetics and the Manipulation of Life: The Forgotten Factor of the Situation.

Danish researchers have shown that genetically manipulated genes (transgenes) introduced into crops, in field conditions can move into nearby weeds. So genetic errors of the kind that happened in Monsanto's canola seeds could spread into the natural environment and permanently change the natural world in ways no one is prepared to understand."

Another direction of modern biotechnology is the insertion into the genome of cultivated plants of genes that make the plant tasteless, not eaten at all, or even poisonous for animal species that feed on its tissues or for “weed” plants that drown out its growth. And this path, despite its apparent attractiveness, is theoretically unpromising. Firstly, "pests" and "weeds" always develop resistance to an artificial gene after some time. Second, over time, there will be other organisms for which an unpalatable plant will be palatable (see also Chapter 6). In addition, the introduction of any new gene into a genome polished by millions of years of evolution will always lead not only to the emergence of toxicity or resistance, but also necessarily to the breakdown of the entire complex genetic system and, thus, not to strengthening, but to weakening the protected organism.

By affecting the content of trace elements and other substances in plants, pesticides can change the nutritional value of plants , as well as their storage capacity. Such an effect was found for OCPs on cereals and legumes. So, for example, the treatment of wheat crops with some fungicides (zineb, bayleton, tilt) against stem rust ( Puccinia causes a decrease in the quality of baked bread.

The negative effect of pesticides on nutritional qualities wheat and potatoes.

Sometimes herbicide treatment can change taste qualities plants , and this can have dangerous consequences. So, after treatment with the herbicide methoxone (2M-4X), buttercups that were previously inedible for livestock begin to be eaten in in large numbers; this leads to severe poisoning and even death of livestock. There are cases where the treatment of fields with herbicides has made economically important plants available for consumption by leaf beetles.

Influencing the course of intracellular and intercellular biochemical processes in plants, pesticides can drastically change the agrotechnical qualities of cultivated crops. For example, herbicides of the group Sim-triazines and urea derivatives block the transport of electrons during photosynthesis, which leads to a change in the nature of plant vegetation. Prometrin inhibits the process of symbiotic nitrogen fixation and promotes the transition of legumes to the mineral type of nitrogen nutrition. As a result, the value of legumes as nitrogen accumulators is sharply reduced. Nitrogen content ( mg/10 plants) changed in soybean: control (without herbicides) – 1493; when treated with promethrin - 1092.

One of the negative consequences of the use of pesticides is danger of destruction of modern genetically very unstable varieties of high-yielding plants due to the rapid accumulation of mutations in them. For example, the use of herbicides such as linuron, cotoran, toluine and THAN on cotton leads to the rapid destruction of the genetic structure of varieties. The same effect is exerted by DDVF (dichlorphos), phthalophos, simazine, chlorophos on wheat varieties, as well as dilor, karbofos, TMTD (thiram) - on tomatoes (in the latter case, the genetic consequences are especially clearly manifested not immediately, but in the second generation).

It has been shown that pesticides can not only change the genetic structure of plant populations, but also cause damage to plants, sterility, ugly growths (morphoses) of vegetative and generative organs. So, in barley crops treated with pesticides, up to 70% of plants with modified ears were found. There are even known cases of culling crops for this reason. Treatment with 2,4-D and phoxime caused an 18-24-fold increase in the number of plants with morphoses in barley. Table 5.2 summarizes the effect of various pesticides (not only herbicides, but also insecticides, acaricides, nematicides and fungicides) on the occurrence of ugly plant forms.

Table 5.2. The effect of some pesticides on the appearance of ugly forms of plants (dwarfism, disruption of the structure of the ovary and ear, flower, leaves, etc.)

Among other examples of the effect of herbicides on plant disease, we note the following.

After the introduction of the usual norms of gameran (terbutrin) and dicuran (chlortoluron), wheat was more affected by powdery mildew pathogens. Aresin (monolinuron) and simazine had the same effect on winter wheat plants. Herbicides such as methoxon (2M-4X), ioxynil, dicamba and some others increased the susceptibility of winter wheat to root rot by an average of 60% compared to the control. Treatment of grain crops with 2,4-D favored the development of diseases such as powdery mildew and Alternaria. This and other herbicides of hormonal action (2,4-DM, 2M-4HP) affect the development of helminthosporosis of bluegrass meadow. herbicides Sim-triazine group, having a high herbicidal activity in corn crops, at the same time stimulate the development of its dangerous disease - blister smut ( Ustilago maydis) .

Under the influence of pesticides change the elemental composition of soils . Some pesticides can increase the content of some micro- and macroelements in plants (nitrogen, phosphorus, calcium, potassium, magnesium, manganese, iron, copper, barium, aluminum, strontium and zinc) and reduce the content of others.

Pesticides can lead to the accumulation of ammonia compounds in the soil. Phosphamide and fluometuron (kotoran) contribute to an increase in the content of nitrates in the soil, and DDT, sevin and HCCH sharply reduce it. The content of nitrates in the soil decreases by 30-40% when using prometrin. Treatment with the herbicide 2,4-D leads to an increase in nitrates in the straw.

A serious and usually underestimated negative consequence of the use of herbicides is a sharp increased soil erosion. The lack of grass cover makes the soil defenseless against wind, rain, and melting snow. On grassless soil, erosion develops rapidly on slopes with a steepness of only 1-2%, i.e. more than 90% of arable land in Russia.

When using herbicides in forestry, mineralization processes are activated, the amount of organic matter in the soil decreases, and the total content of nitrogen and calcium decreases.

In conclusion, we emphasize: negative impact of pesticides on agricultural plants –hard fact . And this impact is much more serious and diverse than advocates of the use of pesticides believe.

The connections between the elements of the biosphere are not only dynamic, but also quite stable. However, a person in the course of his activity often damages these permanent connections, that is, the environment, in which it is enough to break one link, as the whole chain is broken - the biota (the totality of plant and animal organisms). Therefore, under the influence of the anthropogenic factor, the environment is constantly changing and, unfortunately, more often for the worse.

Emissions into the atmosphere of various chemical compounds by industrial enterprises, vehicles, and intensive use of agrochemicals cause great harm to the environment. Falling out with precipitation, they pollute the environment - soil, reservoirs, groundwater, natural lands, seas, air ( rice. one).

Thus, all chemical compounds adversely affect all ecological categories of the biosphere. Instead of natural ones, so-called technogenic ecosystems are being created, landscapes are changing, and inanimate nature is also affected. Considering this negative impact of chemical compounds on the environment, in particular on agricultural landscapes, it is necessary to weaken, which largely depends on general environmental protection measures and human activities aimed at improving trophic relationships in the biological environment.

Rice. 1. Scheme of circulation of pesticides in the environment

Environment is a combination of physical, chemical, biological, as well as social factors that can directly or indirectly, quickly or after some time, affect the biota and human health.

Installed the following forms effects of pesticides in the biosphere:

local action. Direct impact on harmful organisms or indirectly on other organisms, water, soil. The effectiveness of the local action of pesticides is determined by the dose, form, method of application, selectivity of action and the rate of decomposition in the environment.

The aftereffect is close(landscape-regional). According to the duration and nature of the impact of the pesticide on the environment, it depends on the relief, soil and weather and climatic conditions.

Aftereffect remote(regional-basin). Characteristic for persistent pesticides capable of migrating in the form of solutions, suspensions or in a sorbed state with soil colloids into river basins, their floodplains and terraces.

Aftereffect is very distant(global) - impact on the planet as a whole (oceans, land, atmosphere). This is due to the transfer of persistent pesticide substances by air currents, water, cyclones, storms, mass migrations of birds, animals and people, movement Vehicle, transportation of goods, raw materials, food.

Pesticide exposure can result in:

• formation of resistance in harmful organisms;
• impact on plants and animals;
• accumulation and transmission by food chains.

The circulation of pesticides in the environment can occur according to the schemes: air - plant - soil - plant - herbivore - man; soil - water - zoophytoplankton - fish - man.

The state of the environment is assessed against chemical monitoring criteria using standard highly sensitive methods for the analysis of pesticide residues.

Sources and causes of environmental pollution with pesticides

In the environment, pesticides are spread through the air, water, plants, animals, and people who work with them. Nature Conservation and rational use its resources is one of the important problems of our time, from right decision which largely depends on the development of the economy, the safety of life and the preservation of the environment in an ecologically clean state.

At modern level chemicalization of agricultural production in the context of a significant increase in the number and expansion of the range of pesticides, protecting the environment from pollution is extremely important and requires the establishment of strict regulations and a well-organized system for monitoring their observance. The causes of environmental pollution with pesticides are in violation of the regulations for their use, the use of persistent drugs and other technological factors.

An overdose of pesticides. Special situations of pollution of environmental objects arise with increased consumption rates of pesticides. The use of maximum pesticide application rates is the most common cause of environmental pollution. In the treated areas, local contamination is distinguished (overlaps, passages and turns of the unit, the use of uncalibrated or faulty sprayers) and continuous overdoses (caused by errors in calculating the required consumption rate of the pesticide and working mixture, etc.).

Systematic use of persistent pesticides without taking into account the self-cleaning ability of the soil can lead to gradual accumulation and exceeding the MRL.

Use of contaminated sprayers or containers is one of the causes of damage or destruction of sensitive crops with herbicide residues, the toxic dose for which is less than 1 g/ha, such as corn, sugar beet, sunflower, soybean, potato, rapeseed, etc. For the application of herbicides, it is necessary to use separate sprayers. These requirements cannot be met when using special aircraft, so it is necessary to thoroughly clean the equipment from herbicide residues. When washing equipment from herbicides, aqueous solutions of sodium carbonate, ammonia and other electrolytes are used, for ethers and other hydrophobic preparations - mineral oils and aqueous solutions of surfactants. The use of poorly cleaned pesticide containers can lead to negative consequences.

The use of herbicides in sensitive phases of development of cultivated plants. This negative factor is observed when using hormonal drugs (2,4-D, 2M-4X, picloram, dialen, etc.). They are recommended to be used in a phase that is safe for cultivated plants - full tillering of cereals (21-29 phases of ontogenesis), because with earlier or later use of phytohormone analogues, their negative effect on the growth and development of crops, grain yield decreases and its quality deteriorates, and in some cases, the formed grain loses its viability.

Use of untested mixtures of pesticides or their combination with other agrochemicals. AT modern technologies growing crops are widely used mixtures of pesticides and agrochemicals. In the absence of the necessary information about the compatibility of components, their use may be one of the reasons for the negative impact on cultivated plants with unpredictable aftereffects in agrocenoses. Since it is impossible to foresee the effect of all combinations of drugs when used in mixtures, it is recommended to conduct a study of pesticide mixtures before use in order to determine their phytotoxic effects on plants under specific conditions. According to the current regulations on plant protection, mixtures of agrochemicals that are not officially approved for use are strictly prohibited from use.

Mistakes in choosing pesticides may be associated with the absence of a label on the container, violations during storage and the irresponsibility of specialists when performing this work. Among pesticides, there is a group of preparations that must be stored only at positive temperatures. When frozen, physical and chemical changes occur in them, which cause the loss of pesticide action or the appearance of phytotoxicity for cultivated plants.

Use of straw after application of herbicides. Straw of winter crops is widely used as a substrate and mulch in closed ground. And since vegetable crops are very sensitive to a number of herbicides of hormonal action, it is necessary to use straw from fields where these herbicides were not applied.

Pesticide pollution atmospheric air. The movement and movement of part of the pesticide from the place of use by air currents is called drift. The main source of pesticides entering the air is the processing of agricultural crops, forest plantations and subsequent evaporation from the surface of objects. Dispersion of pesticides, the intensity of their pollution of atmospheric air is determined by the characteristics and method of application of the drug, its volatility, the number of treatments, meteorological factors (temperature, wind speed, etc.). The weathering of pesticides from the soil surface is much faster than when the preparations are introduced into the soil, where they are contained in soil colloids. The same substance is weathered from the soil surface at different rates depending on temperature and humidity, concentration and wind speed. Light particles of powdered preparations or wettable powders are easily carried by air. Pellets and briquettes are heavier and therefore tend to settle faster.

Circular tip high pressure and small tip form very small droplets that are easy to carry. Circular tip low pressure and large tip produce large droplets with less drift. The possibility of demolition of part of the pesticide droplets depends on the method of its application. With a lower dispersion height, the working mixture enters the air streams less and is carried less, and vice versa

Aerial spraying is carried out from a height of 3-4 m above the object and at a wind speed of not more than 3 m/s, and when using ground equipment - 3-4 m/s. Violation of these requirements leads to the demolition of working mixtures over a considerable distance. Volatile pesticides high temperature air (22-28 °C) quickly erode, which significantly reduces their pesticidal effect and pollutes the environment. Removal of pesticides from the air occurs with precipitation and by photochemical destruction.

Pollution of atmospheric air with pesticides is characterized by such an indicator as the maximum permissible concentration (MAC). According to sanitary standards maximum acceptable levels pesticide content in the air working area are 0.001-0.05 mg/m 3 .

Pollution and behavior of pesticides in water bodies. Pesticides can enter water bodies directly from the soil or the atmosphere. They enter open water bodies with sewage and melt waters, during aerial and ground processing of farmland and forest plantations, as well as during the direct destruction of weeds, algae, mollusks, and the like.

From the atmosphere, pesticides enter the water with precipitation, during weathering and leaching from the surface into deeper layers of the soil. The movement of pesticides to water occurs due to runoff from the treated surface or as a result of leaching into the lower layers from the soil surface. Runoff and leaching occur when an excess of liquid pesticide hits a surface, or when a surface that contains pesticide residues is exposed to a lot of rain or irrigation water. waste water may enter drainage channels, streams, ponds or rivers, which can carry pesticides over long distances. Pesticides also leach into the lower soil horizons, reaching ground water. Pesticide runoff can cause significant damage to fish and other aquatic life in ponds, streams, lakes and rivers. The distribution of pesticides in the water column depends on their physico-chemical properties (bulk mass, solubility), and the like. The rate of destruction of pesticides in water is affected by its temperature, pH, the level of general pollution, and the properties of the active substance.

Pesticides that have entered water bodies can break down, or, if they are stable, migrate and accumulate in aquatic organisms and mule, which determines their danger to aquatic environment. To characterize the stability of the drug in water, t 50 and t 95 decay are determined.

Stability is assessed on a scale:

• first grade- highly stable drugs (t 95 more than 30 days),
• second– stable (11-30),
• the third– medium stable (6-10),
• fourth- low stability (up to 5 days).

The duration of storage of a pesticide in water determines its effect on water bodies and environmental impact Therefore, when selecting a range of drugs, stability indicators should also be taken into account. The stability of a substance, in addition to its chemical nature, also depends on the form of the drug, the cost rate, and weather conditions.

A feature of pesticides as environmental pollutants is their biological effect on non-target organisms, as well as the ability to exhibit undesirable indirect effects ( rice. 2).

Effects of pesticides on fish and aquatic invertebrates

The main reason for the death of aquatic fauna is the ingress into water bodies and rivers of industrial and domestic effluents containing organic waste and mineral nitrogen components. However, pesticides also cause significant damage to fisheries when they enter the water as a result of wind drift when spraying crops and with water flowing from cultivated fields. Water bodies are directly treated with pesticides to kill mosquitoes, other pests, weeds and algae in canals and paddy fields. Toxicity of various pesticides to plankton, various kinds fish depends on many factors. According to the degree of danger, they can be conditionally placed in the following sequence: insecticides - herbicides - fungicides.

The criterion for the toxicity of a particular drug is the relative hazard coefficient, which is determined by the ratio of the pesticide consumption rate, which is recommended, to the value of the toxic effect for fish of concentration and SC 50, bringing them to the same dimension, taking into account the depth of the reservoir:

• HB- the maximum consumption rate of the drug (active substance) when spraying crops, mg / m 2;
• SK 50- concentration in water, which leads to 50% death of individuals for a certain time, mg/m3 of water;
• h is the depth of the reservoir.

For example, the hazard coefficient for freshwater bazudina fish is 33; Bi-58 new - 0.013; karbofos - 1.0; Sherpa - 2.5-5; sumicidin - 1.8. The greatest danger to fish with organophosphorus compounds is bazudin. Synthetic pyrethroids, despite low consumption rates, have a high hazard ratio. Among herbicides, the least toxic derivatives of carbamic acid.

The danger to aquatic fauna is insecticide spraying of small rivers, local water bodies and coastal zones of large reservoirs.

The danger of pesticides for large deep-water reservoirs is much less due to the fact that the toxicant dissolves large volumes water, and the direct treatment of the reservoir is excluded.

Pesticides can accumulate in plankton, fish in large quantities without external signs poisoning and pose a danger to many parts of the food chain.

Contamination and behavior of pesticides in soil

Pesticides enter the soil in all cases of their use. In the future, a certain part of them decomposes into non-toxic products within several months and does not leave a noticeable negative effect, the other part is stored for years and enters the system of the circulation of substances in nature. Pesticides enter the atmosphere during evaporation, and then fall out with rain, are washed out by precipitation or soil water into deep subsoil layers, are carried by plant roots to the surface with soil solution, enter food products in microquantities and again into the soil. The duration of these processes depends on natural and anthropogenic factors affecting the breakdown of pesticides in the soil.

natural factors. Biological processes are fundamental in the degradation of most pesticides. The biological activity of the soil is determined by its type, genetic layer, pH, content organic matter, hydrothermal regime, aeration conditions and the like. Features of the distribution of soil microorganisms are associated with the geography of the main types of soils. As we move from north to south, soil biogenicity increases. Different microbiological activity of soils is determined by the temperature regime.

The rate of inactivation and decomposition of pesticides depends on the type of soil, the degree of its cultivation, mineral and mechanical composition, etc. Uneven localization of microflora in different genetic soil horizons and their unequal biological activity affect the completeness of pesticide degradation. Therefore, inert and persistent pesticides with high migration ability are the most dangerous for the environment. After penetration into the deep layers of the soil, such preparations can remain for a long time without significant changes.

Soil acidity. For most soil microorganisms, the optimal pH value is 6.5-7.5 (neutral medium). It can be assumed that, within these pH values, the microbiological transformation (decomposition) of pesticides in the soil should proceed more intensively. However, studies show that the pH value of the medium affects the transformation of individual pesticides in different ways. Pesticide activity decreases due to the adsorption of drugs and their degradation products by soil colloids. The degree of adsorption of pesticides largely depends on the content of humus in the soil. Soils with a high content of organic matter are absorbed large quantity pesticides compared to loams and sandy.

Soil moisture. If in the soil more water than it can absorb, it, together with pesticides, easily penetrates into groundwater. Rainfall or over-irrigation can cause this phenomenon.

Soil aeration. Most soil microorganisms are active under aerobic conditions, so more often aeration has a positive effect on the decomposition of pesticides.

Norms of consumption of drugs. Pesticides as biologically active substances should not accumulate in the soil in concentrations that adversely affect the vital activity of microorganisms. Therefore, it is necessary to use pesticides in accordance with the regulations, especially to comply with the consumption rates of preparations, which is extremely important for soil self-purification.

Volatility of pesticides depends on the temperature and humidity of the soil and air. For example, 15 minutes after the application of eptam, its loss from dry soil is 20%, from wet soil - 27%, from wet soil - 44%. This also applies to other volatile preparations introduced into the soil. The adsorption of a couple of volatile pesticides by dry soil is much higher than by wet soil. This allows them to be used in dry soil without the risk of reducing efficiency.

Detoxification of pesticides in soil and other media largely depends on soil properties, weather and climate factors (precipitation, temperature, lighting). They depend on tillage, irrigation, fertilizer use, crop and method of application of drugs. With an increase in temperature and solar insolation activity, the rate of decomposition increases. The shelf life of pesticides in soil depends on the type and extent of their application.

One of the main factors that can prevent soil contamination with pesticides is a scientifically based reduction in the consumption rates of drugs, the frequency of treatments and the optimization of their use. Replacing continuous treatments with strip and edge treatments, the use of tank mixes significantly reduce the cost of preparations per unit area, and, consequently, soil pollution.

Pesticides are substances used to protect plants, agricultural products, wood, leather, wool, cotton products, as well as to destroy animal parasites and control vectors of dangerous diseases.

The name "pesticides" comes from two Latin words "rest" - poison and "side" I kill. The use of pesticides is a common practice in all developed countries. With the use of pesticides, crop losses from pests, diseases and weeds are drastically reduced. It is believed that the use of pesticides allows you to save 1/3 of the potential crop.

More than 10 thousand pesticides are produced in the world, belonging to various classes of chemicals. These are chlorine-organic, phosphorus-organic, mercury-organic, pyrethroid, symtriazine and other compounds. They differ not only in chemical structure, but also in their biological action. Depending on which pests are affected by certain substances, they can be divided into three large groups, in which subgroups are distinguished:

1) pesticides = zoocides (insecticides, acaricides, molluscicides, larvicides, rodenticides, attractants);

2) substances for combating plant diseases (fungicides, bactericides, seed dressings);

3) substances for combating harmful vegetation, as well as regulating the growth and development of plants (herbicides, defoliants, desiccants, retardants, auxins, gibberellins).

The most common classes of chemical compounds are as follows.

1. Organochlorine compounds (OCs): DDT, the gamma isomer of HCCH (hexachlorocyclohexane), chlorobutadione, aldrin, dieldrin, etc., have medium toxicity, their characteristic feature is high persistence, i.e. resistance to decomposition and exposure to environmental factors.

2.Organophosphorus compounds (OPs): chlorophos, karbofos, metaphos, dichlorophos, fozalon, trichlormethafos. They have high insecticidal activity and quickly decompose in environmental objects.

3.pyrethroid : deltamethrin, ambush, cymbush, decis, karate. Like HOS and FOS, these are substances with high insecticidal activity.

4. Triazine : simazine, promethrin, sitrin, burefen, etc.

By their nature, pesticides are divided into chemical and biological. The action of chemical pesticides is based on the toxic effect on harmful organisms. Their use poses an environmental hazard to the environment. The action of biological pesticides (more precisely, biological plant protection products) is based on the use of antagonistic (competitive) relationships between organisms or the use of the waste products of some organisms to suppress others (the use of insects of entomophages, acariphages, microbiological preparations of bitoxibacillin and dendrobacillin against the Colorado squirrel, respectively) . The use of biological plant protection products is environmentally safe for both humans and environmental objects.

The most important characteristics of pesticides are toxicity and persistence.

Toxicity- the property of a chemical substance in a certain amount to cause poisoning of the body. There are acute and chronic toxicity.

Persistence pesticide - the property to persist for a long time in objects of the natural environment without changing the initial toxic properties.

Pesticides can penetrate into the body of an animal through the digestive system (intestinal poisoning), through the respiratory organs (fumigation route), through the integument (skin, mucous membranes) - (contact poisoning).

Acute poisoning pesticide occurs when it is exposed to a single time and is expressed in violation of the vital activity of the organism with a possible fatal outcome. It is accompanied by a rapid development of the effect (disease).

Chronic poisoning occurs as a result of repeated exposure to a pesticide in relatively small amounts and is expressed in a slowly developing disturbance of normal life activity. In addition, there may be a cumulative effect. Under the cumulation understand the ability of the poison to accumulate in the body as a result of incomplete detoxification (neutralization) and withdrawal from the body or enhance its action.

The toxicity of pesticides is different and depends on the amount, routes of entry, duration of action, the state of the organism, environmental conditions, etc.

The measure of toxicity is the dose - this is the amount of a substance that is sufficient to poison the body. Usually, toxicity is expressed as an indicator LD 50, measured in mg/kg. For aquatic organisms, toxicity is expressed by the amount of a substance dissolved in a certain amount of water, i.e. concentration that causes an effect in 50% of the tested organisms (lethal concentration - LK 5 0).

The degree of danger of a substance for an experimental object is characterized by lethal, minimally lethal (or threshold) and sublethal doses or concentrations.

Lethal dose- this is any dose (concentration) that causes the death of the organism.

Threshold, or minimally lethal- the smallest amount of a substance that, under certain conditions (temperature increase, homeostasis disturbance) can cause the death of an organism.

sub-lethal dose- dose (concentration) of a substance that causes a violation of the vital activity of an organism and does not lead to its death (not externally manifested).

The use of pesticides is a common practice in developed countries. agriculture both in crop production and in animal husbandry and veterinary medicine. Their application gives a significant agronomic and economic effect, allowing to reduce crop losses from pests, diseases and weeds by 30-40%. The scale of pesticide use in the world annually ranges from 3 to 5 million tons, of which 34% is used in North America, 45% in Europe, and 21% in other regions.

However, in addition to the high positive effect, the use of pesticides gives rise to a number of environmental problems.

Negative consequences are mainly associated with violation of the regulations for their use (violation of consumption rates, terms of use, careless handling of toxic drugs, getting into areas that are not subject to treatment, etc.). They appear on all objects of the environment (Fig. 4).

1. Air pollution is observed during the processing of crops or forest land. When processing agrocenoses, the species diversity of plants decreases in them, due to which the herbivores living here are deprived of their usual feed. Soil ecosystems are also subjected to negative influence pesticides: soil is contaminated with toxic substances. Over time, pesticide residues decompose, but some of them (persistent) are able to remain in the soil for a long time (up to 5 years or more).

These pesticides include organochlorine pesticides, especially DDT (dichlorodiphenyltrichloromethylmethane), which was previously used as an insecticide, as well as simazine (a class of triazine pesticides) and some others. When simazine is used in corn crops, its residues remain in the soil for up to 5 years and are capable of exerting a phytotoxic (inhibiting plant growth) effect on other crops that should follow corn in the crop rotation. Thus, the use of persistent herbicides leads to disruption of crop rotations.

2. From the soil, undecomposed pesticide residues enter the plants, as a result of which crop products are contaminated with toxic substances. It is quite natural that the quality of such products decreases in terms of hygienic indicators, and their use in food or feed leads to various poisonings of people and farm animals (at the subcellular, cellular, organismal levels).

3. Toxic pesticide residues affect soil biota, inhibiting soil microflora and earthworms, which are important components soil biocenosis.

4. The influence of pesticide residues on representatives of the fauna is diverse. Poisoning of wild animals is possible when pesticides get on the surface of their body (contact poisoning). But more often, poisoning occurs through the use of certain feeds that have been contaminated with pesticides. Pesticide residues migrate from one food link to another, accumulating in the final links of the chain in quantities that can inhibit the reproductive function of animals (sluggishness, decreased potency, etc.) and even cause death.

5. A number of pesticides are mutagens and can cause mutations in animal populations, resulting in the emergence of resistant forms.

The appearance of mutated resistant forms is especially characteristic of insects, in which this property is developed quite quickly and often.

The negative effect of pesticides is manifested in the contamination of drinking water sources with toxic substances and the deterioration of the sanitary condition of water sources. Getting into the reservoir from agricultural land when washed off the fields, when pesticides are blown away by the wind during crop processing and in other ways, they adversely affect aquatic biota, causing poisoning of fish and food organisms for them, and herbicide residues cause a decrease in productivity. aquatic plants. Aquatic organisms, especially planktonic crustaceans such as daphnia, bosmines, moins, etc., are extremely sensitive to water pollution by pesticides. Daphnia die when the water contains 10 -4 - 10 -5 mg/l of dichlorophos, decis, karate, and other organophosphorus, pyrethroid and organochlorine pesticides.

Persistence of pesticides in the environment, their bioaccumulation and transformation . Pesticides that have entered the natural environment are included in the processes of bioaccumulation and biotransformation. In the process of bioaccumulation, a multiple increase in the concentration of a pesticide can occur as it moves along food chains. As a result, not detected by modern control methods, some pesticides and their decay products can be present in environmental objects in very dangerous concentrations. The accumulation of pesticides in the body of wild animals - objects of hunting and fishing - can reach levels when it becomes dangerous to eat them.

Biotransformation processes of pesticides also take place in nature. A significant part of the pesticides released into the environment sooner or later decomposes in the organisms of animals, plants, microorganisms or under the influence of physical and chemical factors of the environment. In the process of decomposition of pesticides, both detoxification of pesticides - the loss of toxic properties by the initial substance, and toxification - an increase in the toxicity of the resulting substances can occur. Thus, the biotransformation of the pesticide dictotophos leads to the formation of monocrotophos and its amide analogue, which have a teratogenic effect. The herbicide atrazine in the process of biotransformation is transformed under the influence of plant enzymes into substances with a stronger mutagenic effect than the original product. There are quite a lot of similar examples.

The process of accumulation of pesticide residues in living organisms, their migration through food chains is especially pronounced in aquatic ecosystems. The magnitude of this process can be characterized by the cumulation coefficient as the ratio of the content of a toxic substance in the next link in the food chain to its content in the previous link. For persistent pesticides, it can reach tens, hundreds and thousands of times. Below is an example of the accumulation of the pesticide DDT in the organisms of an aquatic ecosystem (USA, Lake Michigan) (Table 10).

High level Accumulation of residues of highly toxic persistent pesticides in the highest food link (predators) can reach dangerous levels, leading to the death of animals.

10. Accumulation of DDT in organisms of aquatic ecosystems [Yablokov, 1990].

The toxicity of pesticides to a living organism can manifest itself in both lethal and sublethal effects.

On the human body, the effect of pesticides in sublethal concentrations is manifested in the development of the following pathological processes:

1) a decrease in immunity and an increase in the general morbidity of the body;

2) negative impact on nervous system;

3) violation of memory and ability to abstract thinking;

4) development of pregnancy pathology;

5) the appearance of congenital physiological and anatomical defects (malformations) in offspring;

6) pesticides have a pronounced mutagenic, blastomogenic, carcinogenic and allergenic effect, etc.

Similar pathological processes in pesticide poisoning are observed in farm animals.

To prevent poisoning with any preparations, it is necessary to strictly observe the safety precautions during storage, transportation and work with them.

Ways to reduce the environmental pressure when using pesticides

1. The chemical method in plant protection should be used as a last resort, when other techniques and methods become ineffective.

2. In the case of pesticides, it is necessary to choose such preparations that have less toxicity and persistence.

3. In plant protection, agrotechnical practices should be more widely used, aimed at reducing the number of pests, pathogens, and the accumulation of weed seeds in the soil; apply special methods of tillage, carry out phytocleaning - timely removal of damaged and diseased plants, etc.

4. Biological methods and techniques should also be used more widely in plant protection, using entomophages and acariphages, pathogenic and antagonistic microorganisms and their metabolic products, biologically active substances (attractants, repellents, hormones).

5. Good results gives the use of a genetic breeding method based on the breeding of varieties resistant to diseases and pests, as well as the use of transgenic plants obtained by genetic engineering.

6. Apply an integrated method in plant protection, the essence of which is to different ways to increase the natural mortality of pests and pathogens and to minimize the consumption of pesticides. The method includes a combination biological methods protection, the development of special agrotechnical methods (changing the timing of sowing, the nature of the location of plants, land reclamation, etc.), the breeding of resistant varieties, the use of quarantine measures, etc.

7. Properly apply pesticides, first of all, observe the terms of application and permitted doses, withstand the waiting period (this is the time from the last crop treatment to harvest, mainly from 20 to 30 days). Compliance with the waiting periods, as well as the permitted doses, prevents the accumulation of harmful pesticide residues in crop products and the poisoning of humans and domestic animals.

8. Based on the organizational and economic method: optimization of the structure of sown areas, crop rotation, spatial isolation of agricultural crops, the use of resistant zoned varieties and their periodic renewal, activation and protection of entomophages and acariphages in agrocenoses, land reclamation, etc.

1. Chemical plant protection / Ed. G.S. Gruzdev.- 3rd ed., revised. and additional - M.: Agropromizdat, 1987. - 415 p.

2. Yablokov A.V. Poisonous seasoning: Problems of the use of pesticides and ways of greening agriculture. - M .: Thought, 1990. - 125 p.

Questions for self-control.

1. Pesticides, their purpose and agronomic efficiency of application.

2. Chemical classes of pesticides, division by biological action.

3. Toxicity and its measurement. Ways of penetration of pesticides into the human body. Lethal and sublethal effects of pesticides.

4. Negative impact of pesticides on wild animals.

5. Negative effect of pesticides on soil biocenoses and aquatic ecosystems.

6. Pathological processes in humans at a sublethal level in case of pesticide poisoning.

7. Bioaccumulation and transformation of pesticides.

8. Ways to reduce the environmental pressure when using pesticides.