Ukraine

by Prof. Yu. I. Kundiev 

A specific place among POPs is taken by pesticides, especially chlorinated hydrocarbons. According to the hygienic classification, most of them are categorized as extremely stable substances. DDT, Aldrin, heptachlor, hexachlorcyclohexane (HCCH) were detected in soil 8-12 years after their application. As a rule, these compounds are retained in the upper layer of soil for a long time and migrate to the deeper layers very slowly. Their content in soil depends on a number of factors, such as type of soil, humidity, soil microorganisms, rate of applications. The pesticides load (kg/hectare) in Ukraine is demonstrated in Fig. 1. Till the mid-80-ies most of them were chlororganic pesticides (COP).

A characteristic feature of chloride containing pesticides is their accumulation in the products of both animal and vegetable origin and very slow reduction of residues. They are detected in fruit and vegetables months after they were last applied. Increased concentration of chloride containing pesticides is registered in higher links of the biological (food) chain.

Thus, their content in bionts is one or two orders higher than in water; Aldrin and Lindane were detected in carrots in concentrations by an order higher than in soil.

In a human organism as the final link of the food chain chloride containing pesticides are accumulated in significant quantities, primarily in the organs and tissues rich in fats and lipids. There is proved dependency of DDT accumulation on the volume absorbed.

Most of these substances are metabolized in the organism and for a long time are preserved in fats and lipids in form of the primary compound or metabolites. They may be present in the milk of breast-feeding women. At that, DDT (or other POPs) can be found in the breast milk of women who had never had occupational contact with it. It is usually believed that these substances enter the human organism with food.

A study, carried out in 1986 under the auspices of international organizations and widely referred to since then, used the presence of DDT, HCCH, polychlorinated biphenyls (PCB) as a criterion of environmental pollution. This study was later repeated in many countries, including the former USSR, and in the recent years it was carried out in Ukraine.

In the 40-s, 50-s and 60-s DDT and HCCH were the most widely used pesticides in the USSR. Research carried out then by the team of L.I.Medved (1970) registered the presence of DDT and its metabolites in the fatty tissues and subcutaneous cellular tissue of operators working with the pesticides (5-12 mg/kg, 4 mg/kg average). COPs and their metabolites have been detected and are still detected in the breast milk of women living in different regions of the former USSR, including Ukraine (4,5). Some time ago certain scientists argued that the presence of DDT and other COPs was harmless for the human organism. This was proved to be untrue in numerous epidemiological and experimental studies carried out by L. I. Medved, 1970; Yu. S. Kagan, 1969; S. G. Serebryanaya, 1966, 1967 and others. Additional proof has also been lately received at our institute. Thus, V. F. Demchenko showed that pathological childbirths were registered more often with women having higher COP content in the organism.

In 1971 DDT was officially prohibited in the USSR. Despite this, for more than 10 years after that the Ministry of Health issued temporary permits for its application to protect plants on limited areas. The data on DDT use in the USSR are given in Table 7.

Next in the COP list by the scale of its application was HCCH (a mixture of isomers), which was replaced by Lindane (8). By the late 80-s the application of HCCH was also prohibited. Nevertheless, as late as in 1991 they still used it in minor quantities from the stocks left on the farms.

Diene series COPs Endrin and Isodrin were never used in the former USSR because of their high toxicity. As for Aldrine and Dieldrin, short-term trials of them were held. For example, in 1963 they were applied on cotton plantations in Uzbekistan. Four to five days after the pesticide application acute poisonings were registered among children who had helped in the fields (Yu. I. Kundiev, unpublished data). Soon after that further use of these pesticides was prohibited. Chlordane and heptachlor were used in the former USSR in the 60-s-80-s on a limited scale. They were excluded from the list of permitted preparations in 1986-1990.

Out of the diene synthesis COPs, tiodane (endosulfan) and hexachlorbutadien were used for a longer time. In the early 90s their application was strictly limited.

Among the COPs used widely in the former USSR one can name the class of polychloropinenes (analogue - strobane) and polychlorocamphenes (analogue - toxaphene). The scale of use is represented in Tables 9, 10. At present the use of these substances is prohibited in all the CIS countries due to the high toxicity and persistency in soil, water and other environmental objects.

Their content in root-crops depends on the degree of soil contamination. The highest concentrations were found in carrots, beet roots, potatoes. The pesticides were detected in plants for 150 days running. In water they preserved their toxic properties for more than a year.

In the 60-s-80-s chlororganic acaricides were used in the USSR. The most widely used of them was keltane (dicofol). It is capable of causing embryotoxic and mutagenic effects, and is preserved in soil for more than two years. At present its use is prohibited.

Thus, in the 50-s-70-s pesticides of the first generation - persistent chlororganic compounds - were widely used for plant protection in the former USSR. Millions of hectares of cotton plantations, beet-root, grain, vegetable fields and fruit gardens were treated with these pesticides. And although DDT and HCCH were prohibited in the former USSR much earlier than in other countries, they were in fact still used for some more years in reduced volumes.

Such wide and long application of persistent chlororganic pesticides in the USSR brought about significant contamination of soil, water and other environmental objects in many regions. More than 20% of the analyzed soils in Ukraine contain DDT and the products of its degradation, 4% of soils are contaminated with HCCH.

A major problem today is the storage of large quantities of pesticides which are outdated or prohibited for further use. According to a special survey of the Ukrainian Environmental Ministry such stocks amount to 22 million tons, most of which are persistent chlororganic pesticides.

The storage conditions are different, and mostly inadequate. Together with the long storage time, low quality of containers and packaging, this led to the formation of different compositions of substances, and even possibly of new compounds with unknown properties. Further storage of such quantities of toxic substances in unfit storehouses surely poses a permanent threat to the environment and human health fraught with an environmental catastrophe.

Besides, in the present situation there is real possibility of illegal use of prohibited pesticides. There already are reports of such cases. But it is practically impossible to determine the scope of such unauthorized use or where and how the pesticides are applied.

It is imperative that all the CIS countries should work out and implement organizational, technical and technological measures and conditions to neutralize and dispose of outdated and prohibited pesticides.

This voluminous work should start with making a comprehensive inventory, including chemical identification, sorting and repackaging of unfit pesticides.

Measures for the disposal of unfit pesticides may vary from using them for their original purpose to burning at high temperatures in special furnaces for incinerating toxic wastes, which are extreme alternatives.

In between these extremes and depending on specific circumstances the measures can include processing pesticides at chemical plants, burning pesticides in cement kilns, decontaminating pesticides through chemical and biochemical degradation into harmless substances, burying pesticides in special pits, repackaging pesticides for further safe storage.

Ukraine has developed a draft program for the inventory of unfit pesticides. The pilot project will take less than a year. There are all the necessary pre-requisites for starting this vital work. But the economic situation of the country does not allow to start its financing now.

N Country Year DDT and HCCH HCB