DECREASING THE DANGERS OF THE IMPACT OF LEAD ON CHILDREN IN THE REPUBLIC OF KAZAKHSTAN
doctor of medicine, professor, Deputy General Director of the National Healthy Lifestyle Center, Almaty, Kazakhstan.
candidate of medicine, Executive Director of the Center for Healthcare and Environmental Design,
candidate of technical sciences, assistant professor at the Almaty Institute of Power Engineering and Communications
Received in revised form July 8, 2004
Lead and its toxic compounds are dangerous environmental pollutants. The influence of these substances on the health of human beings, especially children, who are the most vulnerable to the harmful impact of lead, is worthy of special study, for the following reasons:
- lead is widespread (practically everywhere) in places where people reside;
- lead, even in extremely low concentrations in the environment, is capable of having a negative impact on children’s health;
- lead causes significant damage to the human nervous system, which has a negative effect on the intellectual development of the growing generation;
- the primary sources of pollution by lead and lead compounds are of anthropogenic origin, creating the opportunity, through the efforts of society, of regulating such pollution and decreasing the risk to health.
Lead and lead compounds are polytrophic poisons (that is, they act on various organs and body systems), and primarily cause changes in the nervous and circulatory systems, as well as disrupting fermentation reactions and vitamin exchange, and lowering immunobiological activity.
The majority of children subjected to the chemical impact of lead and lead compounds suffer from subclinical effects—that is, effects that have not yet appeared in the form of illness, but which already take their toll on body functions. The results of research show that poisoning by even small doses of lead leads to a disruption of motor and coordination skills in children (including hand-eye coordination), as well as of hearing and sleep, and a stunting of physical development (Perlstein, Attala; Bellinger et al.; Rabinowits et al.; NRC). In its publications, the World Health Organization has repeatedly emphasized that lead is of no chemical or biological importance for the human body. The illnesses caused by lead and toxic lead compounds have a negative effect on the development of society as a whole, since the number of highly gifted individuals is lowered, and the number of people with decreased intellectual abilities is increased (Lead and Health).
It has been discovered that an increase of 1 mcg/dl in the lead content of the blood of preschool-age children leads to a decrease of 0.25-0.50 points in the coefficient of a child’s intellectual development. In addition, the consequences of lead poisoning may appear many years later. For instance, as a result of the study of a group of children in whose blood increased levels of lead were found at the age of two years, disruptions in nervous system activity were discovered ten years later (Markowitz). At the present time, the threshold level of lead poisoning for preschool-age children is considered to be a level of lead in the blood equal to 10 mcg/dl.
The primary sources of lead pollution are discharges from industrial enterprises (Nazarbayev), leaded gasoline (Perlstein, Attala), and lead-containing paints and finishes used in construction and in the manufactire of dishware, toys, and other everyday objects (Bellinger et al.). Other sources also exist (for example, Ayurvedic medicines, traditional forms of cosmetics, and others), but these are encountered only in certain countries of the world.
Long-term research has confirmed the direct cause-and-effect connection between the appearance of the early stages of lead poisoning in children, taking the form of disruption of the central nervous system, and the lead content in dust entering the child’s body orally, through dirty hands. In order for such negative effects to appear in children, the falling of tiny particles of paint, contaminated soil, etc. into the dust is sufficient. In this context, hygienic measures play a significant role in preventing the negative effects of lead on children’s health. The use of therapeutic medicines is less effective, since it has been proven that they temporarily lower the level of lead in the blood, but do not remove it from bone tissues.
In various countries of the world, significant positive experience has been accumulated with regard to decreasing the impact of lead on the health of children. In the United States, thanks to the existence of a special comprehensive program over the course of 20 years, the average lead content in the blood of preschool-age children has been reduced by 80% (Brody et al.). In the Landskron region of Sweden, where the largest center for the processing of lead batteries in Europe is located, the average lead content in the population’s blood was reduced in 10 years from 6.5 to 3.05 mcg/dl (Farago et al.). Over the course of two years, in the city of Zlatna (Rumania), the average concentration of lead in children’s blood was reduced from 40 mcg/dl to 28 mcg/dl, in spite of the fact that discharges from industrial enterprises did not fall during that period (Activity report…).
For the Republic of Kazakhstan, the problem of lead pollution is especially urgent. Not only are deposits of lead ore refined within the country, but large metallurgical enterprises are in operation as well (the Ust-Kamenogorsk Lead and Zinc Combine, the Yuzhpolimetall company, and others). However, to date no unified program has been developed in Kazakhstan to prevent the effects of lead on children’s health.
An analysis of the extent to which the problem has been studied show that Kazakhstani scientists, over the course of decades, have conducted ongoing research into the hygienic aspects of environmental lead in various regions of the country (Granovsky). However, the majority of such studies have been devoted to individual regions or industrial enterprises. Moreover, as a result of the different laboratory methods used by various authors, it is difficult to compare the data obtained.
From 1996 to 2003, a study was conducted in the Republic of Kazakhstan with the support of the Civil Research and Development Fund (CRDF, USA) and the Ministry of Science and Higher Education of the Republic of Kazakhstan, in order to estimate the effect of lead pollution on children’s health. The chief agencies conducting the study were the Center for Healthcare and Environmental Design (Almaty, Kazakhstan) and SHARE International, Inc. (USA). Their research involved the comprehensive study of all possible forms of impact by lead on the health of children in various regions of Kazakhstan. The work was carried out using a unique set of portable equipment (NITON XL-700, ESA LeadCare, Kaulson Laboratories Hematofluorometer, and so forth), as well as stationary laboratory complexes in the United States, including a computerized chemical electron microscope (ElectroMicroProbe), enabling researchers to determine the chemical compounds in which lead was found.
Studies were conducted in the cities of Almaty, Shymkent, Ust-Kamenogorsk, Taldykorgan, Tekeli, Pavlodar, Ekibastuz, and Kyzylorda; more than 1100 children and 27 preschool establishments were examined, more than 5000 analyses of the quality of paints, toys, and dishes performed, and 800 express-surveys of soil pollution taken.
The data obtained showed that the mean level of lead contained in the blood of the preschool-age children examined was 8.82+0.26 mcg/dl. At the same time, lead content higher than the norm was found in the blood of 20.7% of the children. The mean amount by which the level of lead exceeded the norm was 2.4 mcg/dl per child. If we take this level as average for Kazakhstan, the overall loss in intellectual development, calculated for all preschoolers, totals approximately 600,000 IQ points**. The highest number of children with increased lead levels was found in Shymkent (65%), the lowest in Pavlodar (4%).
The loss from an increase in the concentration of lead in the blood of 1 mcg/dl per child is estimated in the United States to be approximately $1200 US (Lead and Health).
As noted above, the primary sources of pollution of the environment by lead and its toxic compounds in Kazakhstan are the following: industrial enterprises, leaded gasoline, and lead-based paints and finishes.
As a rule, such pollution is localized in the zone where the polluting enterprises are located. In the given case, the effects of lead on children’s health may be prevented through planning aimed at reducing the negative environmental consequences of industrial operations, observance of basic hygienic requirements, and provision of special training and information to employees of preschool establishments, medical workers, and parents. In some instances, it is necessary to change the profile of the preschools or move them to a different neighborhood, and also work to restore the damaged environment.
In the majority of Kazakhstan’s regions, increases in the level of lead in blood are observed only in individual children. In most cases, this is tied to the use of lead-based paints in the manufacture of toys (above all those of Chinese manufacture), the use of certain kinds of paints and enamels for decorating homes and courtyards (primarily browns, yellows, or greens), and the use of lead-based finishes in the production of dishware (mainly ceramics from China, Russia, and Kazakhstan).
Such cases of the effect of lead on children’s health may be prevented by strengthening controls over the quality of building materials and household items (in the first place, increasing the role of the Sanitary-Epidemiological Service in the mandatory certification of production, as well as creating specialized and well-equipped laboratories), observing individual hygiene, and improving training and information for preschool employees, medical workers, and parents. Within the framework of the research undertaken in Kazakhstan in 1996-2001, recommendations were developed and employed in the city of Pavlodar, enabling the mean level of lead in the blood of children attending preschool establishments to be reduced by half.
Despite the fact that leaded gasoline, containing tetraethyl lead, is one of the sources of environmental pollution, to date no unified normative legal act regulating its use has been passed in Kazakhstan. The use of leaded gasoline is prohibited only in certain regions of the republic.
It is necessary to prohibit the use of leaded gasoline throughout the Kazakhstan, and to create an active system for monitoring and enforcement. Experience has shown that a complete withdrawal from the use of leaded gasoline—for example, that carried out in the United States from 1976-1991—has led to a reduction of lead levels in the population’s blood of 77%, and a twofold reduction of the concentration of lead in leaded gasoline led to a decrease of 20% in the level of lead in the blood of the population of Great Britain (U.S. Environmental Protection Agency).
In our opinion, in order for a substantial reduction to take place in the effects of lead and toxic lead compounds on the health of children in Kazakhstan, a number of measures must be taken.
Many of Kazakhstan’s industrial enterprises continue to make use of obsolete technology, the complete replacement of which is either not possible at this time, or not justifiable in economic terms. Therefore, these enterprises are unable to strictly observe modern environmental norms.
The impact of lead on children’s health depends largely on individual behavior. Therefore, we recommend that the following basic hygienic requirements be observed:
- conducting daily cleanings, with water, of residential dwellings, carefully cleaning carpeting with a vacuum cleaner;
- changing footwear (and preferably clothing as well) upon entering a home from outside;
- forbidden children to accept food on the street;
-making sure that children wash their hands after returning from outside and before eating;
- not permitting children into building where repairs are taking place, and so forth.
In order to carry out the aforementioned measures, leaders and specialists at agencies of the Sanitary-Epidemiological Service, children’s polyclinics, and educational establishments must not only understand the gravity of the problem, but must possess corresponding qualifications and necessary experience in dealing with it.
Educational seminars should be held for parents as well. Information regarding the dangers of lead intoxication in children and means for preventing it should be distributed widely in the mass media. With the aim of reducing the threat of lead poisoning in children, we recommend the following:
- avoid iron deficiencies in their diet;
- daily intake of up to one gram of calcium.
In formulating a government order for scientific research, priority should be given to hygienic research aimed at developing measures for preventing lead poisoning.
In light of the diverse pathways by which lead can penetrate the body, it is necessary to develop a system of constant monitoring, and to conduct regular and comprehensive studies in order to discover children suffering from the danger of lead intoxication. Throughout the world, the widely accepted practice is to simultaneously conduct observations both of the state of the environment and of the lead content in children’s blood, as a primary marker of pollution. The impact of lead on children is highly individual in nature; two children from the same family may have different levels of lead in their blood, depending on the specific details of their behavior.
The implementation of a program for decreasing the danger of lead poisoning in children requires the adoption of specific solutions for urban design and construction, and the restoration of the natural environment (above all, the soil) at sites that have been subjected to technogenic disruption.
At the present time, no truly effective methods exist for treating children suffering from lead poisoning.
Relying on the criteria developed by the World Health Organization, we can assert that among all of the children studied in Kazakhstan, approximately 5.7% (having lead blood levels higher than 25 mcg/dl) require careful medical examination, and some 0.4% (with lead blood levels of over 55 mcg/dl) are in need of immediate treatment.
The improvement of the current normative and legislative framework in Kazakhstan is of critical importance for programs aimed at decreasing the threat of lead poisoning in children, as current legislation fails to meet the needs of the times.
Taking into account all of the aforementioned issues, specialists at the Ministry of Public Health of the Republic of Kazakhstan have developed a concept and program for the comprehensive study and reduction of the dangers of the impact of lead on the health of the children of Kazakhstan (Decree No. 859, September 16, 2002). The implementation of this program will make it possible to have a real impact on the current situation, to attract investors, and to guarantee that the plans developed by the country’s scientists are adopted and put into practice.
The environment of Kazakhstan began to suffer serious harm during the Soviet period. The country now faces an urgent need to address the Soviet legacy of ecological mismanagement. Between 1949 and 1991 the Soviet government conducted about 70 percent of all of its nuclear testing in Kazakhstan, mostly in the north-eastern area near the city of Semipalatinsk (now Semey). Nearly 500 nuclear explosions occurred both above and below ground near Semipalatinsk, while more than 40 nuclear detonations occurred at other testing grounds in western Kazakhstan and in the Qyzylqum desert. More than 1 million of Kazakhstan’s inhabitants were exposed to dangerous levels of radiation because the Soviet government did not evacuate or even warn nearby populations. In the late 1980s Kazakhs held large demonstrations calling for an end to the nuclear testing, and in 1991 the government of Kazakhstan put a stop to the practice. However, the testing grounds, and perhaps even underground aquifers (water-bearing layers of rock, sand, or gravel), remain highly contaminated. The Nevada-Semipalatinsk Organization, which led the campaign against nuclear testing during the 1980s, has turned its attention to teaching residents of polluted areas how to avoid nuclear contamination. One of every three children born in the Semipalatinsk region has mental or physical defects, and about half the population suffers from immune system deficiencies.
Another ecological disaster area in Kazakhstan is the Aral Sea, which is split roughly in half between Kazakhstan and Uzbekistan. The Aral Sea has shrunk to less than half its former size since the early 1960s, when the Soviet government initiated a drive to increase cotton yields in the arid lands of Central Asia. Excessive irrigation substantially decreased inflow to the Aral, and the Aral’s shoreline began to recede rapidly. This has caused severe environmental problems in the Aral Sea Basin, including the destruction of wildlife habitat as a result of desertification (a process whereby previously habitable or arable land becomes desert). The Aral Sea crisis is also associated with a number of health problems, including respiratory infections and parasitic diseases. Efforts to address the crisis have focused on preventing further shrinkage of the Aral Sea, mainly because the damage is so severe that it is practically irreversible.
Kazakhstan also faces the problem of urban pollution, particularly in its eastern cities, which receive harmful emissions from lead and zinc smelters, a uranium-processing mill, and other industries. In recent years, environmental activist groups in Kazakhstan have begun lobbying for tighter emission controls. Other environmental issues in Kazakhstan include soil pollution from the overuse of pesticides in agriculture and the increasingly polluted waters of the Caspian Sea.