Desenvolvimento de farinhas de osso calcinadas para aplicação como fertilizantes orgânicos de solos: análise físico-química e ecotoxicológica

Abstract

Commercially available calcined bone flours are predominantly of bovine origin and useful for soil improvement. However, the lack of use of other unworn animal sources and methodological standardization in the production of these meals, identified the need for biotechnological exploration of that niche of fertilizer products. The main goal of this research project is to evaluate the effect of different thermal treatments on calcined bone meal from animals slaughtered for commercial purposes. Bovine, ovine, and porcine femurs had the organic matter manually removed, followed by immersion in sodium hypochlorite solution and washing. Then, the bones were calcined separately, in an aluminum grill, applying two heat treatments: the first spent two hours, and the second lasted four hours. The process was repeated in quintuplicate. Subsequently, the calcined bones were crushed in a wooden pestle until obtaining the consistency of flour. For the characterization of each type of calcined bone meal, the following steps were performed: analysis of yield and production costs, chemical analysis, Fourier transform infrared spectroscopy, X-ray diffraction, ecotoxicity assay, and statistical analysis. We verified that the developed flours presented variations in their chemical composition, being more advantageous than those submitted to 4 hours of calcination. Exposure to only two hours generated products with residual organic matter. Regarding the different animal origins, the bovine CBF stood out, as it contains nutritional percentages greater than 40% and 35% of Phosphorus and Calcium, respectively. Additionally, it obtained around 36% yield and had the lowest production costs. The flours tested in this study did not show acute toxicity and are therefore safe. The findings of this study prove the possibility of developing bone meal using standardized protocols for biotechnological application in soil fertilization.