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Tannery sludge are rich in organic matter and N, P, Fe, Mn, Cu, Zn and other nutrient elements and trace elements, at the same time, contain considerable amount of Cr and a small amount of Ni, Cd, Pb and other heavy metal elements. Land use is one of the effective ways to reduce the large amount of tannery sludge and reuse it. Based on the literature about land application of tannery sludge, the properties of tannery sludge and its influence on soil properties and soil plants after entering into the soil were summarized, as well as the risks of oxidation and migration of Cr, and soil salinization after the application of tannery sludge. Proper amount of tanning sludge can improve the physical properties of soil, for example, bulk density, porosity and water holding capacity, and increase the content of organic matter and N, P and K nutrient elements in soil, and stimulate the growth of microorganisms and enzyme activities in soil. How-ever, the application of tannery sludge can significantly increase the accumulation of Cr and salt in the soil, which has a negative impact on the physical and chemical properties of the soil, and there is a risk that Cr (III) will be transformed into Cr (VI) with stronger toxicity and migration ability, thus threatening the activities of microorganisms and plants. Based on the above analysis, the future research prospects were put forward in order to provide reference for the land use of tannery sludge.
Keywords: tannery sludge, land application, soil properties, plants, risk