Pesticides

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Synthetic pesticides

The XX century gave the mankind many strict lessons and one of them is understanding the fact that not always a man acts wisely for his own benefit. Alongside with bloodshed wars, crazy arms race, human imprudence obviously revealed itself in large-scale usage of not enough tested substances which at some moment seemed convenient and useful. Such practice should be substituted with the principle of caution presumption which is one of the most popular modern ideas in the sphere of environmental law. According to it every new achievement of technologies should first of all go through strict check for safety for people and environment. In using pesticides, the necessity of this principle proved to be higher than in any other sphere.

The word “pesticide” itself to great extend outlines the problems related to it. The root “cide” which comes from Latin “kill” directly expresses the purpose of these substances – killing, destroying living creatures, war with nature. The root “pest” now in many world languages means “vermin”, and implies that man divides all creatures into useful for him and harmful denying the latter the right to existence.

“Pesticides” is a wide notion that includes many chemical compounds that have suppressing effect on animate nature. The most widely spread and known are insecticides which kill insects, herbicides which destroy herbs, fungicides directed against fungi and rodenticides which are fatal for rodents. But there exist means against other groups of living creatures: acaricides (acaridae), ichthyocides (fish), nematocides (coelelminth). Besides, pesticides include repellents (substances to repel insects) defoliants (substances to accelerate leaves falling), desiccants (to dry plants on their roots) stimulants and inhibitors of plant growth as well as bactericides and antiseptics. About 700 (according to other data – 860) chemical substances are used as pesticides, and several thousand of medication forms are produced using them (only the Agency of Environmental Protection of the USA registered about 21,000 trade marks).

Mass usage of pesticides started after World War II when most countries were facing difficulties with food products and complicated epidemiological situation. It seemed like pesticides easily solve both problems at the same time. Very soon this charm disappeared, but the desire to find an easy way was so strong that despite growing number of evidence against pesticides, their production was steadily growing from 1940s till the middle of 1980s. Till the beginning of 1990s the growth slowed down a bit but then speeded up again in 1994 reaching the volume of 27.8 milliards now owing to the countries of Asia and Latin America. These two regions now consume one third of world production of pesticides, and further growth is predicted. At the same time according to 1990 data, in developed countries 25 million cases of acute poisonings of agricultural workers with pesticides have place every year. In total in the world, according to evaluations of The World Health Organization, pesticides take away 20,000 lives every year.

Till the middle of 1980s in the USSR more than 3,000 tons of pesticides of 60 denominations were produced. Till the end of the decade USSR occupied the eighth place as for pesticides production. But their great part (30-40%) was also bought abroad. A number of pesticides, including those prohibited in the country such as DDT and other organochlorine compounds, USSR exported to developing countries.

Unfortunately, we have to admit that it was in the USSR that usage of pesticides acquired some the most distorted forms. Violations of basic rules of their usage were so common that could be considered normal rather than exceptional. Pesticides were used without application of necessary protection means and in dangerous ways in imprecise concentrations; they were stored (and are still stored) in unadapted and unequipped premises, people went to the fields after pesticides were applied there without waiting for set period of time. Very often prohibited for usage pesticides were still used “as “exceptionally” or just illegally. The pesticides produced in the country didn’t meet the world standards of quality; very often they contained admixtures which increased their action on living creatures. It is widely known that pesticides or their metabolites can be found in human organisms all over the world including in the areas where they were never applied, for example inhabitants of the Extreme North. Less known fact is that inhabitants of Russian North have several times more pesticides in their organisms than, for example, inhabitants of Scandinavian countries.

In some sense we can say that the problem of pesticides is one of the problems generated by overpopulation of the Earth. Great number of people requires also great amount of food which is mostly produced in the form of plant monocultures which exhaust soils, undermine biodiversity and lead to abnormal reproduction of certain species which are fed by these monocultures. These species are immediately referred to the class of “pests”, and in order to limit their number people first of all try to go the shortest and the cheapest way of mass chemical destruction. But this way turns out to be far from the most advantageous.

Generations of poisons

It is usually believed that during the last century (the epoch when pesticides were used the most) there were three generations of pesticides. The first of them appeared almost simultaneously with the World War I, and according to any today’s measures it was something absolutely terrible as it consisted mostly of usual poisons toxic for humans and spine animals even more than for those “pests” against which they were used. These were compounds of arsenic and mercurial organic compounds, and what is more they were used in terrible concentrations.

Appearance and introduction of the second generation of means to fight the nature were also connected to war between people – the World War II. In the war time substance to control insects are especially needed because of overall hardships and mass movement of people bugs spread very quickly. That is why the whole world welcomed reinvented or applied for the first time to fight against insects organochlorine pesticides, including now notoriously known DDT and hexachloran which the same that 1,2,3,4,5,6-hexachlorcyclohexan (HCCH). It was then that other less known organochlorine pesticides appeared, among them aldrin, dieldrin, heptachlor, chlordane, toxaphene, mirax – later were included into “dirty dozen” of the most hazardous contaminants of the environment which today are unanimously condemned by the world community. Important fact is that nine substances from “dirty dozen”, that is two thirds are pesticides which once were gladly used as “wonderful remedy” for problems. To the class of organochlorine compounds are referred also a few herbicides including 2-4-D which is still used.

The second class of compounds which includes many pesticides of the second generation organophosphorus compounds including ethers of thiophosphorous acid. Among compounds of this class there are insecticides octamethyl, thiophos, mercaptophos. And it’s not by accident that to the same class refer substances produced as military poisonous substances for chemical wars well known as sarin and soman. The difference in the degree of poisonous characteristics of chemical weapons and pesticides is so little that there were a number of cases when militaries used pesticides storages as strategic reserve for potential military usage, and pesticides production often was the basis for producing fighting poisoning substances and vice versa. The same generation of pesticides includes carbamate herbicides and insecticides, derivatives of urea having herbicide action, various synthetic fungicides, bactericides, zoocides, nematocides.

As early as in 1950s negative consequences of using pesticides of the second generation became known. It gave impetus to appearance of the third generation which included mainly synthetic perethroids and hormonal substances. Their main characteristic difference is their ability to cause faster destruction and more intense poisonous action which allows decreasing the norms of usage. Because of this characteristic their usage implies that the content of pesticides remnants in agricultural products decreases but the probability of accidents is higher (according to the report of the World Health Organization as of 1988, the number of such accidents reaches one million every year , however, these estimates are considered to be very understated).

Among pesticides of the third generation we can mention sumicidine, ambush, cymbush and decis.

As we see, change of pesticides generations is a sad and senseless process: no sooner had people got disappointed in one class of substances having understood how harmful they are than they switch to another class being somehow sure that this one will be fine. Pesticides were introduced so quickly that, for example, in the USSR before some hazardous pesticides got prohibited, there were not developed any hygienic norms for them. Even in the USA, the country with more developed environmental legislation, in the 1980s no more than 40% of used pesticides went through all necessary tests. The principle of caution presumption should put the end to this stupid chain.

Development of new pesticides has become more active but it becomes more complicated because demands to it on the world market become stricter. For example, in Europe the costs of development of one pesticide increased from 25 million ECU in 1975 to 125 million ECU in 1992. The way of a pesticide from laboratory to a counter lasts for about 10 years, and the whole period spent on its development is up to 20 years. In order to find one perspective pesticide, it is necessary to sort out dozens of thousand substances.

Are pesticides beneficial?

It is no wonder that chemical enterprises do their best to promote received with such a difficulty pesticides on the market. According to evaluations made by American Institute of worldwide research, marketing measures of pesticides producers are the main hindrance for dissemination of more environmentally safe ways of conducting agricultural industry.

Few people realize to what extent ways of development of our civilization depend on inertia – inertia of thought as well as inertia of investments. It’s enough to make one step on the way which because of lack of knowledge seemed easier, and since that time all means and efforts, all people who found on this way their means of existence, and sometimes even means of getting fabulous wealth, will be directed in this way even when it finally becomes clear that this way leads to a deadlock. Today we have such a situation in nuclear industry; there is a similar situation, though a bit less obvious, in the agriculture.

It would be better to invest the funds spent on production, advertisement and usage of pesticides into development of alternative methods of agricultural production. Most probably with the volume of information and scientific potential we have we could get the same harvests as with application of pesticides but now without harm for people and environment. But stereotypes supported by advertising from pesticides producers pose a hindrance. Here “advertising” should be understood not only directly. Chemical companies sponsor certain research works and even institutes dealing with search for “proofs of safety” of pesticides, organization of publications in mass media with the purpose of convincing the society.

UN Food and Agriculture Organization (FAO) adopted a Codex of distribution and usage of pesticides which prohibits inaccurate and ungrounded advertising of these substances. However, selective research of pesticides advertising conducted by American NGOs revealed many serious violations of the Codex.

Once it was believed that “expenses of using pesticides” paid back in 5-12 times. But this quantity was calculated without taking into consideration the costs of harm to environment and people’s health. Just economic loss because of killing effect of pesticides on insects-pollinators which is easy to calculate is 30-40% of the profits gained. We speak not only about insecticides – still widely used herbicide 2,4-D is deathly for bees, and on the other hand insecticide lindane proved to be able to suppress growth of barley. One of the most obvious examples is the fact that in the period between 1952 and 1975, as a result of poisoning, fish industry of the Azov basin lost 2 milliards rubls worth of fish.

It is not possible to increase effectiveness of pesticides because the basic principle of living nature – the principle of changeability – comes into effect. Usage of certain pesticide makes “pests” develop immediate and effective selection according to resistance to that very pesticide. After 3-4 generations quantity of affected species is restored if their natural enemies proved to be sensitive to this pesticide (being in a higher position than the targeted species in the nutrition chain they prove to be more affected). For example, malaria mosquitoes which became one of the first targets of pesticides and which were always used as examples to prove the main successes of chemicalization, have developed resistance to all pesticides used against them, and spread of the disease which they transmit even increased by 1990. Another classical example is with cotton-growers from Peru who as early as in the middle of 1950s experienced negative consequences of using poisoning chemicals. At the beginning they were fighting with seven main species of “pests”, but soon they had to fight with 13 species of pests because as a result of killing insects-pests, species which before were not very numerous multiplied, and all 13 species became highly resistant to pesticides. At present over 900 species from different branches of nature (insects, acaridae, microorganisms, plants, nematodes, and rodents) are resistant to certain pesticides, and because pesticides are still used, their number is growing. On the territory of former USSR there are about 150 of resistant species. In Japan in 1965 it was necessary to control about 473 species of “pests” on vegetable fields, and in 1989 their number grew to 725. Finally, more than ten species of insects developed resistance to all existing kinds of pesticides. Among them there are cockroaches, flies, Colorado beetle, diamond-back moth.

Therefore, there is no connection between increase in pesticides usage and growth of harvests. As a bright example here can serve the former Soviet Union where the increase in pesticides usage many times overdid the growth of harvests. The costs of chemical treatment of grain was about 30% of total costs. The same situation was in other countries which were very keen on pesticides. In the 1980s 26% of the total costs of Nicaraguan cotton were due to pesticides.

A war against living world

The harm caused to the living nature by pesticides cannot be measured precisely but we can say for sure that is immense. Two factors are main here: first, that all synthetic pesticides are substances alien to living nature and are not subject to metabolic decomposition and the second that all of them are capable of bioaccumulation, that is they are contained in living organisms in bigger concentration than in the environment. The most harmful pesticides are DDT, heptachlor, HCCH, that is first of all organochlorine pesticides but not only these. The process of bioaccumulation makes senseless the notion of “permissible dose” of poisonous chemicals because even if used in very little doses, they will accumulate in organisms.

Sensibility to pesticides of animals of different kinds, even congenerical, may be very different; therefore, laboratory tests on one or even several species do not provide objective results. Most often an animal does not die directly because of poisoning but it gets weaker because of it and becomes a victim of predators (and as a result passes the toxin to them), diseases or severe weather conditions. The nature of pesticides toxicity is various – it can be carcinogen or mutagen effect, impact on respiratory, endocrine, immune, nervous systems. Organisms of marine animals are especially contaminated with pesticides. As far as terrestrial mammals are concerned, the can be affected by pesticides “accidentally” in the result of agricultural usage of insecticides and herbicides as well as purposefully, for example when rodents are being killed. For both mammals and birds the most affected became the process of reproduction, as inability to produce healthy and numerous posterity is equal to death for a species. Also, for birds very disastrous effect has elimination of their food basis – insects; that is how people “paid back” to their old helpers in the matter of controlling “pests”.

As far as fish is concerned, pesticides are the second after industrial pollution factor of reducing fish reserves of many countries. Especially dangerous for fish are highly toxic perethroids pesticides of the third generation. In ponds pesticides are not often used, they are mostly washed there from fields. In the USA only in 1988 the procedure of testing new pesticides was supplemented with the solubility test; in this country this characteristic which influences the capability of substances to contaminate superficial and underground waters is still not taken into consideration. About 30% of cases of fish death in Russian ponds are considered to be caused by pesticides, especially by granosan which is used to treat grain. Usually not only fish but also Crustaceans become victims.

It is absolutely obvious that pesticides also destroy natural balance of complex soil ecosystems ruining in this way the grounds of fertility. Herbicides, if applied many times, destroy microscopic soil algae. In some areas of India and Indonesia because of such practice soils became absolutely sterilized and dead.

Every year, month and day brings new facts of pesticides action on living nature. Most of these facts couldn’t and cannot be predicted by developers of chemical poisons. It is extremely difficult to trace systematic action on the living nature, and, in order to trace all possible consequences, one should be the God.

For all who draw a pesticide to environment will die by it…

It is obvious that even the creator of pesticides didn’t avoid their deathly impact. Poisonings of people with pesticides are divided into acute and chronic ones and to quantitatively evaluate others is very hard. Chronic poisonings cannot be evaluated quantitatively (though it is clear that they are numerous). As far as acute poisonings are concerned, according to official statistics their number in different countries is regularly decreasing. According to evaluations of American researchers, up to 40% of people who professionally are related to production and application of pesticides have symptoms of chronic poisoning according to biochemical blood indexes. But this is not the only group of risk endangered by the action of pesticides. Here we should mention also people living on the outskirts of places where pesticides are used. They get pesticides together with food products or water if they drink water from wells situated not far from burials of unused and prohibited pesticides. In Tadzykistan in the middle of 1970s, among people who suffered form acute poisonings with pesticides, only 23.9% were professionally related to them. Statistics for Uzbekistan are similar. These two countries which at that time were republics of the Soviet Union were regions where pesticides were widely and extensively used on their whole territory. In 1967-72 in the USSR 3,761 people got acute poisonings through food products. No conclusions were made after these accidents, and the data though not secret, were not made public.