The Anatomy of a Toxic Cloud
The dust that rises from the Aralkum Desert, the name for the exposed seabed of the former Aral Sea, differs from typical desert dust. It is an aerosolized mixture, carrying chemicals from decades of intensive agriculture and industrial activity. Soviet-era irrigation projects, which diverted the Amu Darya and Syr Darya rivers to feed vast cotton fields, caused the sea to shrink dramatically since the 1960s. As the water evaporated, salts, agricultural chemicals, and industrial pollutants became concentrated in the remaining water and finally settled into the sediment.
Today, frequent dust storms—occurring up to 10 times annually—scour this exposed and contaminated surface. These storms transport millions of tons of dust and salt each year, creating plumes that stretch for 400 kilometers. The aerosol composition contains hazardous materials. Analysis shows large quantities of salt, with dust containing up to 90% salt in the winter. Embedded within this saline matrix are residues of numerous pesticides, including organochlorines like DDT (dichlorodiphenyltrichloroethane), HCH (hexachlorocyclohexane), toxaphene, and the organophosphate pesticide phosalone. Many of these, such as DDT and toxaphene, were banned in Western countries due to their carcinogenic effects. The dust also contains heavy metals like lead, mercury, and cadmium from industrial sources and fertilizers that washed into the sea.