# Phosphogypsum Recycling: A Review of Environmental Issues, Current Trends, and Prospects
Years of waste storage from the production of mineral fertilizers in Ukraine has resulted in the formation of anthropogenic phosphogypsum deposits, which amount to 15.2 million tonnes in Rivne region [2], and 421.11 tons of phosphogypsum has accumulated in Vinnitsa region of Ukraine [3]. The U.S. Environmental Protection Agency prohibits the use of phosphogypsum because of its radioactivity. For example, phosphogypsum from Central Florida has an average of 26 pCi/g radium, and that from North Florida has 10 pCi/g radium. An exception is made for phosphogypsum with an average concentration of less than 10 pCi/g radium, which can be used as an agricultural amendment, but not for other purposes [4]. It is important to note that the content of radioactive elements in phosphogypsum is related to the raw material used in industrial processes. China also has significant production of phosphogypsum, and the five largest provinces in terms of production are Hubei, Yunnan, Guizhou, Sichuan, and Anhui [5]; hence, they these also have large storage sites. Poland also has significant phosphogypsum storage facilities. More than 5 million tons of apatite phosphogypsum has been accumulated in the waste dumps of the Wizowski Chemical Plant (Poland). These wastes contain rare-earth elements, which are listed as \"critical\" raw materials in the European Union (EU) [6]. In Russia, there is over 500 million tons of phosphogypsum accumulation at existing ammonium phosphorus production facilities, which accumulated over all the years of their operation [7]. The negative environmental impact of phosphogypsum dumps can be manifested in the contamination of groundwater and surface water, soil, and vegetation cover by substances seeping through the protective screen, as a result of their evaporation and washout from the dump by atmospheric precipitation as well as airborne emission under the influence of weathering and dusting. The dump is a source of hydrodynamic impact on the environment, causing changes in groundwater levels, which leads to negative phenomena in the residential area, such as alienation and pollution of land areas and the transformation of the natural landscape. The large dumping of phosphate fertilizer production waste has serious consequences for the marine environment, which was studied in [8]. For example, the dumping of phosphogypsum affects the phosphorus cycle with a high content of authigenic phosphorus, especially in the Gulf of Gabes [8]. As studied in [9], phosphogypsum consisting of calcium sulphate and other complementary salts enters seawater as particles. After the particles dissolve, the concentration of heavy metals may affect near the release point. This is a significant environmental problem, especially in the Atlantic Ocean around two locations: Safi and Yorf Lasfar, where the Moroccan phosphate industry emits large quantities of this waste [9]. A study [10] characterized the formed layers of foam from the discharge of phosphogypsum into coastal waters, which can float on the surface and be passively transported to remote areas to understand their role in the behavior of pollutants in the marine environment [10]. Overview of Studies on the Environmental Impact of Phosphogypsum Accumulation and Storage These specific conditions should be considered when choosing a method for removing and storing phosphogypsum in dumps:  
* the production capacity;
* the amount of phosphogypsum that must be removed;
* the remoteness of the extraction components from the phosphogypsum storage site;
* the availability of storage land (unsuitable for other uses);
* the dump topography;
* the climatic conditions;
* the geological and hydrogeological conditions at the phosphogypsum storage site. To create dumps, it is necessary to allocate large areas. Often, these areas exceed the size of industrial sites of the production itself. Thus, P2O5 production requires an area of 1.2 \(\times\) 1.2 km with a blade height of 15 m to store phosphogypsum for 20 years [11].