Oxygen isotope ratios of merrillite and chlorapatite in the Martian meteorites ALH84001 and Los Angeles have been measured by ion microprobe in multicollector mode. O values of phosphate minerals measured in situ range from 3 to 6‰, and are similar to Martian meteorite whole-rock values, as well as the O of igneous phosphate on Earth. These results suggest that the primary, abiotic, igneous pho...

In the last decades considerable attention has been given to naturally occurring radioactive material (NORM). Within this frame, of particular concern is the phosphate fertilizer industry. In Brazil, four main industries (Ultrafertil, Copebrás, Fosfertil and Bunge Fertilizantes) are responsible for the production of 1.2x10 6 tons per year of P2O5. Phosphogypsum is the by-product of the phosphor...

Aspergillus sp PS 104, a soil isolate had excellent potential to solubilize rock phosphate in vitro. The process was influenced by the presence of various concentrations of local loess (red soil). The simultaneous occurrence, in our experiment, of high levels of solubilized phosphate and synthesized citric acid, together with the lowest reached pH values, confirmed the role of citric acid in th...

Recent human population increase has been enabled by a massive expansion of global agricultural production. A key component of this "Green Revolution" has been application of inorganic fertilizers to produce and maintain high crop yields. However, the long-term sustainability of these practices is unclear given the eutrophying effects of fertilizer runoff as well as the reliance of fertilizer p...