Phosphorus is a non-renewable element essential for the existence of life and also for food security. This resource has the property of limiting plant growth, becoming a fundamental part of agricultural production. On the other hand, when this element is present in high concentrations in aquatic environments, it can start a phenomenon called eutrophication, which causes a series of changes in biological succession processes and strongly negative impacts on species’ biodiversity and wealth. In this context, this work aimed, from an extensive bibliographical review, to gather strategic and essential information related to phosphorus sustainability, provoking a reflection regarding scenarios that involve this indispensable nutrient, focusing on the current situation of the State of São Paulo, Brazil, an important case study, both for the Brazilian and international scenario, by a gathering of data on the current situation of two of the main watersheds in the corresponding region. Relevant technologies used for phosphorus removal in eutrophicated environments are also addressed. Finally, the possibility of reusing the nutrients present in eutrophicated water bodies as an alternative source of phosphate fertilizer for agriculture is demonstrated. nonrenewable non renewable security growth production hand eutrophication species wealth context aimed review sustainability nutrient Paulo Brazil study scenario region addressed Finally demonstrated

The phosphorus used as fertilizer in agriculture is extracted from phosphate rocks, which after extraction reacts with sulfuric acid, releasing phosphoric acid, a raw material for the fertilizer industry. Studies point to a possible depletion of world reserves of phosphate rock in the next 50-100 years. A phosphorus scarcity is closely linked to global food security, given the dependence of soil fertilization to maintaining agricultural productivity within the current patterns of agribusiness. The application of fertilizers in soil and the sanitary sewers have been historically responsible for the larger eutrophication of water environments. In recent years, phosphorus has been seen as a finite resource and extremely important for the maintenance of the agricultural productivity. Therewith it is necessary investments to improve of fertilizers practices soils, safe technologies of organic waste reuse such as animal waste and phosphorus recovery, both released into water resource. Taking into account the depletion scenario of phosphorus deposits and eutrophication of water bodies, the water and phosphorus scarcity are among the most urgent environmental issues of the XXI century. Economic development, protection of public health, and maintenance of aquatic life are dependent of water availability and quality.

Neste estudo, foi desenvolvido um teste de toxicidade rápido, utilizando-se a bactéria Klebsiella oxytoca como organismo-teste. Ensaios com Escherichia coli foram usados como referência. A inibição do crescimento bacteriano foi avaliada por um sistema de análise por injeção em fluxo (FIA) com detecção condutométrica do CO2 produzido durante o processo respiratório. Os resultados foram expressos em termos de CE50 (concentração efetiva). A bactéria K. oxytoca foi mais resistente que a E. coli. A ordem de sensibilidade da K. oxytoca em relação aos metais foi Hg2+ > Cd2+ > Cu2+ e para E. coli, Hg2+ > Cu2+ > Cd2+. Para o detergente Laborhex 2 (princípio ativo: digluconato de clorexidina), o CE50 foi 1,55 ± 0,32 mg L-1 e 0,32 ± 0,10 mg L-1 para K. oxytoca e E. coli, respectivamente, enquanto que para o detergente Riodeine Degermant (princípio ativo: iodeto de polivinilpirrolidona-PVP-I), ambas as bactérias apresentaram sensibilidades bem semelhantes, 11,0 ± 1,7 mg L-1 e 12,0 ± 2,0 mg L-1, respectivamente.

In this study, the Klebsiella oxytoca bacterium was used as a test organism in short-term toxicity evaluations, and Escherichia coli was used as reference. The inhibition of bacterial growth was quantified by flow injection analysis (FIA) via conductometric measurements of the CO2 produced during respiration. The results were expressed as effective concentration (EC50) values. K. oxytoca was more resistant than E. coli in respect to growth inhibition. The metal sensitivity order for K. oxytoca was found to be Hg2+ > Cd2+ > Cu2+ and Hg2+ > Cu2+ > Cd2+ for E. coli. The sensitivity to the Laborhex 2 detergent (active ingredient: chlorhexidine digluconate) was 1.55 ± 0.32 mg L-1 and 0.32 ± 0.10 mg L-1 for K. oxytoca and E. coli, respectively. The bacteria showed comparable sensitivities to the Riodeine Degermant detergent (active ingredient: polyvinyl pyrrolidone-iodine-PVP-I), of 11.0 ± 1.7 mg L-1 and 12.0 ± 2.0 mg L-1, for K. oxytoca and E. coli, respectively.