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SOCIETY SHOULD BE PROTECTED FROM THE METAL THREAT

S.L.Davydova

Institute of Petrochemical Synthesis

The Ecological Women’s Assembly has been active since 1944, uniting within its membership women and youth of Russia and other former Soviet states. Among the many aspects of environmental protection of concern is the problem of chemical toxicants, including metals (see Table 1).

Listed in order of degree of human sensitivity to toxic metals, the metals are ranked as follows: Hg > Cu > Zn > Ni > Pb > Cd > Cr > Sn > Fe > Mn > Al. The sensitivity variations are not uniform.

Living organisms have special mechanisms of heavy metal detoxification. In response to the toxic action of Pb2+, Cd2+, and Hg2+, for example, the liver and kidneys increase the synthesis of low-molecular beta proteins, which contain cysteine in their structure. The high content of sulfhydryl groups in cysteine promotes the combination of metal ions into strong complexes, resulting in some level of detoxification.

But it is clear that we must protect ourselves from this “metal” threat.

At one time the main anthropogenic sources of lead releases into the environment were lead-based paints, lead-containing pesticides (now forbidden), and lead in soils around some industrial enterprises. Now the main source of lead pollution is automobile fuel. Vehicle exhausts account for up to 80 percent of the total lead content in the atmosphere. Using ethylized gasoline with a high lead content results in widespread heavy metal pollution of the atmosphere.

In cities overloaded by motor transport, lead concentration in the atmosphere exceeds background values by 20 to 30 times. Street dust sometimes contains up to 1,000 milligrams of lead per kilogram. Oxides and heavy metal salts are almost indestructible, and they gradually accumulate in the environment in areas where people live.



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OCR for page 137
The Role of Environmental NGOs: Russian Challenges American Lessons - Proceedings of a Workshop SOCIETY SHOULD BE PROTECTED FROM THE METAL THREAT S.L.Davydova Institute of Petrochemical Synthesis The Ecological Women’s Assembly has been active since 1944, uniting within its membership women and youth of Russia and other former Soviet states. Among the many aspects of environmental protection of concern is the problem of chemical toxicants, including metals (see Table 1). Listed in order of degree of human sensitivity to toxic metals, the metals are ranked as follows: Hg > Cu > Zn > Ni > Pb > Cd > Cr > Sn > Fe > Mn > Al. The sensitivity variations are not uniform. Living organisms have special mechanisms of heavy metal detoxification. In response to the toxic action of Pb2+, Cd2+, and Hg2+, for example, the liver and kidneys increase the synthesis of low-molecular beta proteins, which contain cysteine in their structure. The high content of sulfhydryl groups in cysteine promotes the combination of metal ions into strong complexes, resulting in some level of detoxification. But it is clear that we must protect ourselves from this “metal” threat. At one time the main anthropogenic sources of lead releases into the environment were lead-based paints, lead-containing pesticides (now forbidden), and lead in soils around some industrial enterprises. Now the main source of lead pollution is automobile fuel. Vehicle exhausts account for up to 80 percent of the total lead content in the atmosphere. Using ethylized gasoline with a high lead content results in widespread heavy metal pollution of the atmosphere. In cities overloaded by motor transport, lead concentration in the atmosphere exceeds background values by 20 to 30 times. Street dust sometimes contains up to 1,000 milligrams of lead per kilogram. Oxides and heavy metal salts are almost indestructible, and they gradually accumulate in the environment in areas where people live.

OCR for page 137
The Role of Environmental NGOs: Russian Challenges American Lessons - Proceedings of a Workshop TABLE 1 Metal Properties Properties Cd Co Cu Hg Ni Pb Zn Biochemical activity H H H H H H H Toxicity H M M H M H M Carcinogenicity   H     H     Concentration in aerosols H L H H L H H Ease of spreading H H L H L H L Mobility H H H H H H H Tendency to bioconcentration H H M H H H M Ability to accumulate H M H H M H H Complex formation M L H M L L H Tendency to hydrolysis M L H M M M H Solubility H L H H L H H Persistence L H H L H L H H—high M—moderate L—low activity Entering the atmosphere from exhaust gases of automobiles and then accumulating in the top layers of the soil, lead enters the human body through the gastro-intestinal path, as well as by inhalation. Lead is delivered by the blood and accumulates in bones, the liver, the kidneys, and the brain. Lead irreversibly affects the nervous system, impedes functioning of the reproductive system, affects the kidneys, and causes mental and physical retardation in children. Especially dangerous is the effect of lead on children, who, when inhaling dust, receive approximately five times more lead for their body weight than adults. Also, lead assimilates in children at a level several times higher than in adults. According to the World Bank, lead pollution of the air from motor transport has become one of the three main risk factors for health in Central and Eastern Europe. The UN Committee on Sustainable Development considers a general prohibition of ethylized gasoline a primary health protection task for the global population. The plan for complete cessation of leaded gasoline production was discussed at the Conference of the European Environmental Ministers in 1998 in Denmark. The parallel reduction of lead levels in human blood in the United States and the decreased use of leaded gasoline since the middle of the 1980s is clear. Also, it is interesting that in 1997, The Alliance to End Childhood Lead Poisoning (U.S.) issued a brochure entitled Myths and Realities of Phasing Out Lead Gasoline (see Table 2). The necessity and possibility of a complete change to unleaded gasoline are obvious.

OCR for page 137
The Role of Environmental NGOs: Russian Challenges American Lessons - Proceedings of a Workshop TABLE 2 Myths and Realities of Phasing Out Lead Gasoline Myth Reality Lead poisoning is not a problem worthy of attention. Lead’s effect on people’s health is extremely dangerous and is certain. Use of leaded gasoline is not the cause of lead poisoning. The direct relationship between the level of use of leaded gasoline and lead content in man’s blood is well known. Old automobiles cannot use unleaded gasoline. Intensive investigations and experiments confirm that all automobiles can operate on unleaded gasoline. The only known substitute for lead— benzene—is a well known carcinogen. Most well-known replacement additives make tetra-ethylized gasoline safer than leaded gasoline. The change to unleaded gasoline requires large material expenditures. The change to unleaded gasoline is economically effective for vehicle owners, oil refining enterprises, and society as a whole. The change to unleaded gasoline is practically an unsolvable problem for developing countries. The change to unleaded gasoline has real advantages, especially for developing countries. When humans take in a combination of metals from the environment (during inhalation of polluted air, consumption of chemically contaminated food and water, and through the skin and mucous membranes), they are subjected to severe impacts of these toxicants. The combined effect of these toxicants is complicated because a living organism reacts to each toxicant differently: in some cases with adaptation (frequently temporary) and sometimes with sharp negative reactions. Frequently during medical examinations of people living in ecologically unfavorable regions, changes in the characteristics of blood are discovered. Also, the attributes of chemical intoxication are found (sometimes even exclusively) among children and older persons. Varying responses to the impact of chemical toxicants depending on sex differentiation have also been noted.

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