A category of chromium (Cr)-containing fertilizers is represented by the fertilizers deriving from byproducts of tanning process. Their use is widespread because of their good agronomic response due to the high content of slow release or- ganic nitrogen (N) and carbon (C). They do not represent an environmental hazard because only the non-toxic form of Cr(III) is present. Productive processes may involve chemical, enzymatic or thermal hydrolysis. The final product is characterized by different contents of peptides and free amino acids depending on the type of hydrolysis. Legislation concerning Cr-containing fertilizers is controversial because often do not consider any scientific evidences; nevertheless, the European Union, the United States and countries as Italy, do not set the restriction to Cr(III) and generally only the presence of the toxic form, Cr(VI), is limited. Depending on its two main oxidation forms, Cr issue has been studied for many years. Several authors confirmed that Cr(VI) is carcinogenic, while Cr(III) is an essential trace element in human and animal diet. In soil Cr(III) has low mobility, whereas Cr(VI) is highly water soluble. However Cr(VI) in soil is quickly reduced to Cr(III); on the contrary oxidation of Cr(III) to Cr(VI) is rarely possible because particular conditions must occur. Only a very small fraction of Cr in soil is available to plant uptake and its translocation in edible parts is limited because it is immobilized in roots as Cr(III). Therefore risks of environmental pollution using these fertilizers are negligible; on the contrary they have positive environmental and agronomical effects. The aim of this review is to deal with the category of the organic fertilizers containing Cr derived from tannery processes focusing on its chemical, productive, legislative, environmental and agronomical aspects. Special attention is given to the ambiguous issue of Cr briefly summarizing the most important studies of the last forty years.
Cite this paper
C. Ciavatta, C. Manoli, L. Cavani, C. Franceschi and P. Sequi, "Chromium-Containing Organic Fertilizers from Tanned Hides and Skins: A Review on Chemical, Environmental, Agronomical and Legislative Aspects," Journal of Environmental Protection, Vol. 3 No. 11, 2012, pp. 1532-1541. doi: 10.4236/jep.2012.311169.
 S. I. Shupack, “The Chemistry of Chromium and Some Resulting Analytical Problems,” Environmental Health Perspectives, Vol. 92, 1991, pp. 7-11.
 C. Ciavatta and P. Sequi, “Evaluation of Chromium Release during the Decomposition of Leather Meal Fertilizers Applied to the Soil,” Fertilizer Research, Vol. 19, No. 1, 1989, pp. 7-11. doi:10.1007/BF01080680
 C. Ciavatta and C. Gessa, “Chromium-Containing Fertilizers and Their Production,” In: S. Canali, F. Tittarelli and P. Sequi, Eds., Chromium Environmental Issues, Franco-Angeli Editore, Bologna, 1997, pp. 61-82.
 C. Ciavatta, L. Vittori Antisari and P. Sequi, “Carat- teristiche Chimiche dei Principali Concimi a Base di Cuoio Torrefatto Disponibili in Italia,” Agricoltura Mediterranea, Vol. 119, 1989, pp. 66-73.
 Commission Regulation (EC), “Laying Down Detailed Rules for the Implementation of Council Regulation (EC) No. 834/2007 on Organic Production and Labelling of Organic Products with Regard to Organic Production, Labelling and Control,” Commission Regulation (EU) No. 271/201, 2010.
 Code of Federal Regulations (CFR), “Standards for the Use or Disposal of Sewage Sludge,” Environment Protection Agency, Title 40 (Protection of Environment), Part 503, 2010.
 Federal Register (FR), Vol. 60, No. 206, 1995, pp. 54763- 54770.
 D. Lgs. 29 aprile 2010, n. 75, “Riordino e Revisione della Disciplina in Materia di Fertilizzanti, a Norma dell’Arti- colo 13 della Legge 7 Luglio 2009, n. 88,” Gazzetta Ufficiale n. 121 del 26 maggio, 2010.
 A. Kabata-Pendias and H. Pendias, “Chromium,” In: A. Kabata-Pendias and H. Pendias, Eds., Trace Elements in Soils and Plants, 3rd Edition, CRC Press, Boca Raton, 2011.
 C. Ciavatta, L. Vittori Antisari and P. Sequi, “A First Approach to the Determination of the Presence of Humified Materials in Organic Fertilizers,” Agrochimica, Vol. 32, 1988, pp. 520-526.
 R. L. Chaney, J. A. Ryan and S. L. Brown, “Development of the US-EPA Limits for Chromium in Land-Applied Biosolids and Applicability of these Limits to Tannery By-Product Derived Fertilizers and Other Cr-Rich Soil Amendments,” In: S. Canali, F. Tittarelli and P. Sequi, Eds., Chromium Environmental Issues, Franco-Angeli Editore, Bologna, 1997, pp. 229-295.
 Draft-WG Fertilizers, Regulation (EC) 2003/2003 of the European Parliament and of the Council of 13 October 2003 Referred to Fertilizers.
 P. Sequi, A. Benedetti, S. Canali and F. Tittarelli, “Aboliti negli Usa i Limiti di Cromo nei Fertilizzanti,” L’Informatore Agrario, Vol. 53, No. 9, 1997, pp. 35-37.
 National Academy of Sciences, “Distribution of Chromium in the Environment,” Committee on Biologic Effects of Atmospheric Pollutants, Chromium: Medical and Biologic Effects of Environmental Pollutants, Washington, 1974.
 M. Yibing and P. S. Hooda, “Chromium, Nickel and Cobalt,” In: P. S. Hooda, Ed., Trace Elements in Soil, Wiley-Blackwell, New Jersey, 2010.
 National Academy of Sciences, “Properties of Chromium,” Committee on Biologic Effects of Atmospheric Pollutants, Chromium: Medical and Biologic Effects of Environmental Pollutants, Washington, 1974.
 S. E. Fendorf, “Surface Reactions of Chromium in Soils and Waters,” Geoderma, Vol. 67, No. 1-2, 1995, pp. 55- 71. doi:10.1016/0016-7061(94)00062-F
 A. M. Ure and M. L. Berrow, “The Elemental Constitu- ents of Soils,” In: H. J. M. Bowen, Ed., Environmental Chemistry, Royal Society of Chemistry, London, Vol. 2, 1988, pp. 92-204.
 H. J. M. Bowen “Environmental Chemistry of the Elements,” Royal Society of Chemistry, Academic Press, London, 1975, pp. 123-125.
 D. C. Adriano, “Chromium,” In: D. C. Adriano, Ed., Trace Elements in Terrestrial Environments: Biogeochemistry, Bioavailability, and Risks of Metals, 2nd Edition, Springer-Verlag, New York, 2001, pp. 315-348.
 S. P. McGrath, “Chromium and Nickel,” In: B. J. Alloway, Ed., Heavy Metals in Soils, 2nd Edition, Blackie Academic and Professional, London, 1995.
 E. E. Cary, W. H. Allaway and O. E. Olson, “Control of Chromium Concentrations in Food Plants. 2. Chemistry of Chromium in Soils and its Availability to Plants,” Journal of Agricultural and Food Chemistry, Vol. 25, No. 2, 1977, pp. 305-309. doi:10.1021/jf60210a049
 C. D. Palmer and P. R. Wittbrodt, “Processes Affecting the Remediation of Chromium-Contaminated Sites,” En- vironmental Health Perspectives, Vol. 92, 1991, pp. 25- 40. doi:10.1289/ehp.919225
 G. Choppala, N. Bolan, M. Mallavarapu and Z. Chen, “Sorption and Mobility of Chromium Species in a Range of Soil Types,” In: R. J. Gilkes and N. Prakongkep, Eds., Proceedings of the 19th World Congress of Soil Science, Soil Solutions for a Changing World, Brisbane, 1-6 August 2010, pp. 239-242.
 R. J. Bartlett, “Chromium Cycling in Soils and Water: Links, Gap and Methods,” Environmental Health Per- spectives, Vol. 92, 1991, pp. 17-24. doi:10.1289/ehp.919217
 A. M. Zayed and N. Terry, “Chromium in the Environment: Factors Affecting Biological Remediation,” Plant and Soil, Vol. 249, No. 1, 2003, pp. 139-156.
 B. R. James, “The Challenge of Remediating Chromium-Contaminated Soil,” Environmental Science and Technology/News, Vol. 30, No. 6, 1996, pp. 248-251.
 E. W. Huffman Jr. and W. H. Allaway, “Chromium in Plants: Distribution in Tissues, Organelles and Extracts, and Availability of Bean Leaf Cr to Animals,” Journal of Agricultural and Food Chemistry, Vol. 21, No. 6, 1973, pp. 982-986. doi:10.1021/jf60190a008
 A. K. Shanker, C. Cervantes, H. Loza-Tavera and S. Avudainayama, “Chromium Toxicity in Plants,” Envi- ronment International, Vol. 31, No. 5, 2005, pp. 739-753.
 S. P. McGrath, “The Uptake and Translocation of Tri- and Hexavalent Chromium and Effects on the Growth of Oat in Flowing Nutrient Solution and Soil,” New Phy- tologist, Vol. 92, No. 3, 1982, pp. 381-390.
 A. Zayed, C. M. Lytle, J. H. Qian and N. Terry, “Chro- mium Accumulation, Translocation and Chemical Speci- ation in Vegetable Crops,” Planta, Vol. 206, No. 2, 1998, pp. 293-299. doi:10.1007/s004250050403
 E. E. Cary, W. H. Allaway and O. E. Olson, “Control of Chromium Concentrations in Food Plants. 1. Absorption and Translocation of Chromium by Plants,” Journal of Agricultural and Food Chemistry, Vol. 25, No. 2, 1977, pp. 300-304. doi:10.1021/jf60210a048
 C. Cervantes, J. Campos-García, S. Devars, F. Gutiérrez- Corona, H. Loza-Tavera, J. C. Torres-Guzmán, R. Mo- reno-Sánchez, “Interaction of Chromium with Microorganisms and Plants,” FEMS Microbiology Reviews, Vol. 25, No. 3, 2001, pp. 335-347.
 R. A. Skeffington, P. R. Shewry and P. J. Petersen, “Chromium Uptake and Transport in Barley Seedlings (Hordeum vulgare),” Planta, Vol. 132, No. 3, 1976, pp. 209-214. doi:10.1007/BF00399719
 T. Mimmo, L. Cavani, R. Reggiani, C. Marzadori and C. Gessa, “Interactions of Organic and Inorganic Chromium Species with Ca-Polygalacturonate,” Biology and Fertility of Soil, Vol. 44, No. 3, 2008, pp. 521-526. doi:10.1007/s00374-007-0238-2
 D. R. Sauerbeck, “Plant, Element and Soil Properties Governing Uptake and Availability of Heavy Metals de- rived From Sewage Sludge,” Water, Air and Soil Pollution, Vol. 57-58, No. 1, 1991, pp. 227-237.
 K. N. Jeejeebhoy, R. C. Chu, E. B. Marliss, G. R. Greenberg and A. Bruce-Robertson, “Chromium Deficiency, Glucose Intolerance and Neuropathy Reversed by Chromium Supplementation, in a Patient Receiving Long-term Total Parenteral Nutrition,” The American Journal of Clinical Nutrition, Vol. 30, 1977, pp. 531-538.
 A. Mordenti and G. Piva, “Chromium in Animal Nutrition and Possible Effects on Human Health,” In: S. Canali, F. Tittarelli, and P. Sequi, Eds., Chromium Environmental Issues, Franco-Angeli Editore, Bologna, 1997, pp. 131- 151.
 EFSA (European Food Safety Authority), Panel on Food Additives and Nutrient Sources Added to Food (ANS), “Scientific Opinion on the Safety of Trivalent Chromium as a Nutrient Added for Nutritional Purposes to Foodstuffs for Particular Nutritional Uses and Foods Intended for the General Population (Including Food Supplements),” EFSA Journal, Vol. 8, No 1732, 2010, pp. 1-46.
 WHO (World Health Organization), Regional Office for Europe, “Inorganic Pollutants,” In: Air Quality Guidelines for Europe, 2nd Edition, WHO Regional Publications, European Series, No. 91, Copenaghen, 2000, pp. 123-135.
 J. B. Vincent, “Recent Advances in the Nutritional Bio- chemistry of Trivalent Chromium,” Proceedings of the Nutrition Society, Vol. 63, No. 1, 2004, pp. 41-47.
 E. G. Offenbacher, H. Spencer and H. J. Dowling, “Meta- bolic Chromium Balances in Men,” The American Journal of Clinical Nutrition, Vol. 44, 1986, pp. 77-82.
 G. Santoprete, “Total Chromium Content in Foodstuffs and Evaluation of the Average Amount of Chromium Uptake,” In: S. Canali, F. Tittarelli and P. Sequi, Eds., Chromium Environmental Issues, Franco-Angeli Editore, Bologna, 1997, pp. 153-179.
 P. Sequi, C. Ciavatta and L. Vittori Antisari, “Organic Fertilizers and Humification in Soil,” In: R. A. Baker, Ed., Organic Substances and Sediments in Water, Vol. 1. Humic and Soil, Lewis Publ. Inc., Chelsea, 1991, pp. 351- 367.
 S. Silva, “Impiego di Concimi Organici a Base di Cuoio Torrefatto, Determinazione delle Concentrazioni di Cromo nei Vegetali e Valutazione delle Possibilità di Inquinamento delle Falde Freatiche,” Annali della Facoltà di Agraria dell’Università Cattolica del Sacro Cuore, Sede di Piacenza, Vol. 17, 1977, pp. 1-38.
 A. Benedetti, M. T. Dell’Abate and F. Alianiello, “Mobility and Bioavailability of Chromium in the Soil,” Fresenius Environmental Bulletin, Vol. 1, 1992, pp. 323-329.
 M. Govi, C. Ciavatta, L. Sitti, G. Bonoretti and C. Gessa, “Influence of Leather Meal Fertilizer on Soil Organic Matter: a Laboratory Study,” Fertilizer Research, Vol. 44, 1996, pp. 65-72. doi:10.1007/BF00750693
 C. Giacometti, L. Cavani, P. Gioacchini, C. Ciavatta and C. Marzadori, “Soil Application of Tannery Land Plaster: Effects on Nitrogen Mineralization and Soil Biochemical Properties,” Applied Environmental Soil Science, 2011, 9 p.
 S. Silva and B. Beghi, “Problemi Inerenti l’Impiego di Concimi Organici Contenenti Cromo,” Annali della Facoltà di Agraria dell’Università Cattolica del Sacro Cuore, Sede di Piacenza, Vol. 19, 1979, pp. 31-47.
 A. Benedetti and C. Ciavatta, “Alcuni Aspetti Relativi alla Produzione e all’Impiego Agronomico dei Concimi a Base di Cuoio Idrolizzato ed al Cromo in Essi Con- tenuto,” Agricoltura e Ricerca, Vol. 170, 1998, pp. 63-72.
 C. Ciavatta, D. Montecchio e P. Sequi, “Applicazione di un Test Rapido per la Determinazione del Potere Ossidante del Terreno nei Confronti del Cromo,” Acqua Aria, No. 9, 1992, pp. 875-879.
 S. Mocali, “Studio della Diversità Microbica in Suoli Concimati con Cuoio Idrolizzato,” Ph.D. Thesis, Uni- versità degli Studi di Firenze, Florence, 2003.
 A. Benedetti and M. T. Dell’Abate, “Studi Preliminari sull’Effetto del Cromo sull’Attività Microbiologica del Terreno. Interazione Cromo-Sostanza Organica,” Istituto Sperimentale per la Nutrizione delle Piante, Vol. 14, 1988, pp. 1-15.
 S. Silva, C. Baffi and G. M. Beone, “Agronomical Trials with the Use of Chromium-Containing Fertilizers,” In: S. Canali, F. Tittarelli and P. Sequi, Eds., Chromium Environmental Issues, Franco-Angeli Editore, Bologna, 1997, pp. 83-100.
 Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals Ammonia, Acids and Fertilizers, 2007.