Chromium-Containing Organic Fertilizers from Tanned Hides and Skins: A Review on Chemical, Environmental, Agronomical and Legislative Aspects

摘要: A category of chromium (Cr)-containing fertilizers is represented by the deriving from byproducts tanning process. Their use widespread because their good agronomic response due to high content slow release or- ganic nitrogen (N) and carbon (C). They do not represent an environmental hazard only non-toxic form Cr(III) present. Productive processes may involve chemical, enzymatic or thermal hydrolysis. The final product characterized different contents peptides free amino acids depending on type Legislation concerning Cr-containing controversial often consider any scientific evidences; nevertheless, European Union, United States countries as Italy, set restriction generally presence toxic form, Cr(VI), limited. Depending its two main oxidation forms, Cr issue has been studied for many years. Several authors confirmed that Cr(VI) carcinogenic, while essential trace element in human animal diet. In soil low mobility, whereas highly water soluble. However quickly reduced Cr(III); contrary rarely possible particular conditions must occur. Only a very small fraction available plant uptake translocation edible parts limited it immobilized roots Cr(III). Therefore risks pollution using these are negligible; they have positive agronomical effects. aim this review deal with organic containing derived tannery focusing productive, legislative, aspects. Special attention given ambiguous briefly summarizing most important studies last forty