An Ecological Disaster Zone with Impact on Human Health: Aral Sea

Abstract

Salt lakes all over the world have been falling during the last century, and they continue to do so. Water withdrawal from their tributaries is one and in many cases main reason for that. Since prehistoric times, the size and shape of the Aral Sea changed depending on the amount of water arriving at the lake. The Aral Sea system is in equilibrium when the amount of water flowing in equals the amount of water evaporating over the year. During the 1950s, the government of the former USSR decided to increase the areas used for agriculture in the river valleys of the Syr Darya and the Amu Darya. To this end, water was and still is deviated from the rivers by thousands of open trenches being unsealed and leading to a massive loss of water by evaporation and seepage. In consequence, less water was and is arriving at the Aral Sea and its size is shrinking dramatically. Especially on its eastern shoreline even a small decrease in the water level leads to the exposition of large areas of former sea bottom because the lake is very shallow. Cities like Aralsk and Munyak formally located directly on the seaside are now completely surrounded by the steppe far away from the water. Although the shrinking of the Aral Sea was an economic disaster for the population living on the coast, the population in the river valleys increased significantly. Today, the major part of Uzbekistan's population is working in this area, and in Kazakhstan there are also millions of people depending on the irrigation water taken from the tributaries of the Aral Sea. The area around the Aral Sea was declared to be a “zone of ecological disaster,” and small subsidies are (still) paid to its inhabitants. Most of the former fishermen moved away to other lakes. In consequence of the breakdown of the economic background the social structure in the population changed completely and people are suffering from unemployment and the lack of any economic perspective. However, studies performed up to now could not prove the assumption that the health of the local population impaired because of environmental pollutants having their origin in the river valleys of the Aral Seas tributaries. There is no doubt that the health of inhabitants of the area is severely affected by the environmental conditions, but not by single contaminants. People living in the Syr Darya valley and, most probably, in the Amu Darya valley suffer much more from pesticide pollution than those living in the former shoreline area of the Aral Sea. Owing to the use of certain pesticides, high concentrations of dioxins and dibenzofurans have been detected in their bodies. Water is a valuable resource and probably the most important economic factor in the countries of Central Asia. The problems of the Aral Sea cannot be solved in the short term. The problems are a result of economic decisions made in the 1950s within a different political context on the basis of a Soviet Union-wide organized economy. Now that small countries are struggling for survival of their local economies, there is, at least in the nonoil producing countries, not enough economic power for a rapid change. However, the area of the Aral Sea will enlarge with an increasing amount of water left over in the Syr Darya and the Amu Darya, even if the Aral Sea probably will not regain its former size during the next generation.