Every year, many tons of salts reportedly are carried as far as 800 kilometers away. Regional experts assert that salt and dust storms from the Aral Sea have raised the level of particulate matter in the Earth's atmosphere by more than 5%, seriously affecting global climate change. The Aral Sea disaster is only the most visible indicator of environmental decay, however. The Soviet approach to environmental management brought decades of poor water management and lack of water or sewage treatment facilities; inordinately heavy use of pesticides, herbicides, defoliants, and fertilizers in the fields; and construction of industrial enterprises without regard to human or environmental impact. Those policies present enormous environmental challenges throughout Uzbekistan. Natural hazards: NA  Environment – current issues: shrinkage of the Aral Sea is resulting in growing concentrations of chemical pesticides and natural salts; these substances are then blown from the increasingly exposed lake bed and contribute to desertification; water pollution from industrial wastes and the heavy use of fertilizers and pesticides is the cause of many human health disorders; increasing soil salination; soil contamination from agricultural chemicals, including DDT  Environment – international agreements: "party to:" Biodiversity, Climate Change, Climate Change-Kyoto Protocol, Desertification, Endangered Species, Environmental Modification, Hazardous Wastes, Ozone Layer Protection, Wetlands "signed, but not ratified:" none of the selected agreements  Large-scale use of chemicals for cotton cultivation, inefficient irrigation systems, and poor drainage systems are examples of the conditions that led to a high filtration of salinized and contaminated water back into the soil. Post-Soviet policies have become even more dangerous; in the early 1990s, the average application of chemical fertilizers and insecticides throughout the Central Asian republics was twenty to twenty-five kilograms per hectare, compared with the former average of three kilograms per hectare for the entire Soviet Union. As a result, the supply of fresh water has received further contaminants. Industrial pollutants also have damaged Uzbekistan's water. In the Amu Darya, concentrations of phenol and oil products have been measured at far above acceptable health standards. In 1989 the Minister of Health of the Turkmen SSR described the Amu Darya as a sewage ditch for industrial and agricultural waste substances. Experts who monitored the river in 1995 reported even further deterioration. In the early 1990s, about 60% of pollution control funding went to water-related projects, but only about half of cities and about one-quarter of villages have sewers. Communal water systems do not meet health standards; much of the population lacks drinking water systems and must drink water straight from contaminated irrigation ditches, canals, or the Amu Darya itself.