Change in the water quality of the Aral Sea in Uzbekistan, Central Asia

抄録

The Aral Sea is a large closed lake located in the arid area of Central Asia. The water level of the Aral Sea was heavily depending on the amount of water contributed by two major tributaries, Amu-Darya and Syr-Darya. In the past 60 years, it was the world’s fourth largest lake in area. However, its area has decreased rapidly, and its water salinity have become high. They decrease in Aral Sea area was caused by the large scale irrigated agriculture which started in 1950’s, especially in the Aral Sea basin. The study investigates the changes in the chemical characteristics of Aral Sea water in Central Asia in 2015 compared with in 1965 and 1994. Results indicated that the current major ion concentrations were higher than in 1965 and 1994. However, Ca²⁺ concentration showed different trends.