Search results for "Phosphorite"
showing 3 items of 3 documents
Influence des phosphates naturels et des mycorhizes à vésicules et à arbuscules sur la croissance et la nutrition minérale de Zizyphus mauritiana Lam…
1998
Rock phosphate and vesicular-arbuscular mycorrhiza effects on growth and mineral nutrition of Zizyphus mauritiana Lam. in an alkaline soil. The influence of vesicular-arbuscular mycorrhizae (VAM) and rock phosphate (RP) was studied on jujube (Zizyphus mauritiana Lam.), a multipurpose fruit tree in Sahelian agroforestry systems. Jujubes were inoculated or not by Clomus manihotis Howeler, Sieverding & Schenck in an alkaline sandy soil to which were added five levels of RP (12 % of P) : 0.00, 0.31, 0.62, 1.25 et 2.50 g P/kg of soil, equivalent to 0, 775, 1 550, 3 125 et 6 250 kg P ha -1 . The jujubes seedlings grew poorly without mycorrhizal colonization and without RP applications (figures 1a…
Polycyclic aromatic hydrocarbons and trace metal contamination of coastal sediment and biota from Togo
2011
The state of contamination of tropical environments, particularly in Africa, remains a relatively under explored subject. Here, we determined polycyclic aromatic hydrocarbon (PAH) and trace metal concentrations in coastal sediment and biota samples (fish and mussels) from Togo (West Africa). In the sediments, the ∑21 PAH concentrations ranged from4 ng g(-1) to 257 ng g(-1), averaging 92 ng g(-1). Concentration ratios of low molecular weight PAHs (2-3 rings) versus high molecular weight PAHs (≥4 rings) were always lower than 1 (ranging from 0.08 to 0.46) indicating that high molecular weight PAHs were dominant in all sediment samples, and that PAHs originated mainly from anthropogenic combus…
Direct determination of total mercury in phosphate rock using alkaline fusion digestion
2014
The aim of this work was to develop a new method to determine the mercury (Hg) concentrations in phosphate rock using a dedicated analytical instrument (the DMA80 Tricell by Milestone) that employs an integrated sequence of thermal decomposition followed by catalyst conversion, amalgamation and atomic absorption spectrophotometry. However, this instrument underestimates Hg concentrations when phosphorite and apatite rocks are investigated with a classic thermal decomposition treatment that complies with US EPA method 7473. Therefore, to improve the recovery of total Hg, we performed alkaline fusion digestion (AFD) directly inside the furnace of the instrument, using BCR(32) as a certified r…