Integrated Geoecological Monitoring and Environmental Risk Assessment of Potash Industrial Facilities under Arid Climatic Conditions

In the dry, sun-scorched landscapes of Central Asia, the ground tells a story of both human industry and natural fragility. Here, where rain is scarce and the wind is a constant force, the earth holds a valuable resource: potash. This mineral is essential for making fertilizers that help grow food for a hungry world. However, extracting and processing potash leaves behind massive piles of waste rock, known as halite, which is essentially salt. In wet climates, rain might wash these salts away or dilute them, but in arid regions, the lack of water and the intensity of the sun create a different problem. The wind picks up fine, salty dust from these waste piles and carries it across the land, settling on soil and water. This process, called secondary salinization, turns fertile ground into barren, salty earth and poisons the water supply. Understanding how this invisible cloud of salt moves and how it damages the environment is crucial for protecting the land and the people who depend on it.

A team of researchers from Uzbekistan has now mapped this invisible threat in detail, focusing on the Dehqonobod potash industrial region in southern Uzbekistan. This area is one of the largest potash facilities in Central Asia, where the climate is hot, dry, and windy. The scientists wanted to understand exactly how the salt from the waste dumps travels through the air, settles on the ground, and seeps into the water. They built a comprehensive monitoring system that combined field measurements with computer modeling to track the movement of salt particles, the salinity of the soil, and the quality of the water. Their goal was not just to measure the damage, but to create a clear picture of the risk zones so that future land management could be more effective.

The researchers found that the waste dumps act as a long-term source of salty dust. When the wind blows, it lifts tiny salt particles into the air, creating a plume that spreads outward from the industrial site. Using a model designed for dry, windy conditions, they tracked how the concentration of this dust changes as it moves away from the source. The results were stark: right next to the waste piles, the air was thick with salt, with measurements of larger dust particles reaching 185 micrograms per cubic meter. As the wind carried this dust further, the concentration dropped rapidly. At a distance of just half a kilometer, the levels were still high, but by the time the dust traveled ten kilometers away, the concentration had fallen to a background level of 25 micrograms per cubic meter. This exponential drop showed that the most severe atmospheric impact is concentrated within a three-kilometer radius of the waste dumps, with the danger fading significantly beyond that point.

This airborne salt does not just disappear; it settles on the land, turning the soil salty. The team measured the electrical conductivity of the soil, a standard way to determine how much salt is present. In the areas closest to the waste dumps, the soil was heavily saturated, with conductivity values exceeding 8 decisiemens per meter, a level that is toxic to most plants. The researchers observed a clear pattern: the closer the soil was to the source of the salt, the higher the salinity. At a distance of three to five kilometers, the soil showed moderate salinity, and beyond five kilometers, the salt levels returned to normal, stable conditions. The wind was the primary driver of this spread, carrying the salt along a specific path and creating a distinct zone of degradation that followed the direction of the prevailing winds.

The impact did not stop at the soil; it also reached the water. The researchers analyzed the water in the area and found that the same salt migrating through the air was also contaminating the groundwater and surface water. Near the waste dumps, the water was highly mineralized, containing high levels of total dissolved solids, sodium, and chloride. At half a kilometer from the source, the water contained 6,200 milligrams of dissolved solids per liter, making it far too salty for most uses. As the distance from the industrial site increased, the water quality improved steadily. Ten kilometers away, the water contained only 980 milligrams of dissolved solids, returning to a much safer, background level. The study confirmed that the salt moving through the air eventually settles and dissolves into the water, creating a cycle of contamination that affects the entire local ecosystem.

To bring these three elements together—the air, the soil, and the water—the researchers created a unified risk map. They combined their data on dust, soil salt, and water quality into a single index that could visualize the danger across the landscape. This map clearly showed three distinct zones. The high-risk zone, where the environment is under the most severe stress, extends three kilometers from the waste dumps and processing facilities. In this area, the air is dusty, the soil is salty, and the water is mineralized. A moderate-risk zone stretches from three to five kilometers out, where the impacts are noticeable but less severe. Beyond five kilometers, the risk drops to low levels, and the environment remains relatively stable. The map also highlighted that the danger is not uniform in all directions; it is most intense along the path of the dominant wind, confirming that the wind is the main engine driving this environmental transformation.

The study also revealed a strong connection between these different parts of the environment. The amount of salt in the air was directly linked to how salty the soil became, and both were closely tied to the mineralization of the water. This means that the problem cannot be solved by looking at just one part of the system; the air, soil, and water are all part of a single, interconnected chain of events driven by the wind and the waste. The researchers noted that in wet climates, rain helps wash salts away, but in this dry region, the lack of rain and the high evaporation rates trap the salt, making the problem worse and longer-lasting.

Based on these findings, the researchers suggest that cleaning up these sites requires a different approach than what is used in wetter parts of the world. Because the salt is so soluble, using large amounts of water to wash it away could actually make things worse by creating highly salty runoff that poisons the groundwater. Instead, they propose methods that focus on stopping the wind from picking up the dust in the first place. This could involve physically covering the waste piles, stabilizing the surface, or planting salt-tolerant vegetation that can hold the soil in place. The integrated monitoring system they developed provides a scientific blueprint for managing these risks, allowing officials to see exactly where the danger lies and to plan reclamation efforts that protect the land and water for the future. By understanding how the salt moves and where it settles, the region can better manage its industrial growth without sacrificing its fragile arid environment.