RESUMEN
The concentration of metals in Brazilian soil under no-tillage (NT) and an area under native vegetation (NV) was determined by inductively coupled plasma mass spectrometry. The applied method was based on microwave-assisted acid digestion using HNO3, HCl, H2O2, and HF. The accuracy of the method was evaluated by analyzing two certified reference materials (BCR-142 and RS-3). The relative standard deviation for all target elements was below 8% indicating an adequate precision and the limit of detection ranged from 0.03 µg g(-1) (Cd) to 24.0 µg g(-1) (Fe). The concentrations of Al, As, Ba, Cd, Cu, Fe, Mg, Mn, Ni, Pb, Sr, and Zn in the different layers (0-10, 10-20, 20-40, and 40-60 cm) were determined in two types of soils, located in Paraná State in Brazil. The soil layers analysis revealed a different behavior of metals concentrations in soil samples under NT and NV. The obtained results showed a clear impact of anthropogenic action with respect to specific metals due to many years of uncontrolled application rates of limestone and phosphate fertilizers.
Asunto(s)
Monitoreo del Ambiente/métodos , Espectrometría de Masas/métodos , Metales Pesados/análisis , Suelo/química , Brasil , Monitoreo del Ambiente/estadística & datos numéricos , MicroondasRESUMEN
The objective of this work is to verifying the consume of the minerals K, Na, Fe, Mg, P, S-SO4 (-2), B, N Total Kjedahl (NTK), NO3 (-)-N, and NH4 (+)-N in the production of bacterial cellulose by Acetobacter xylinum, according to the medium and the manner of cultivation. The fermentative process was in ripe and green coconut water. K and Na were determined by flame emission photometry, Mg and Fe by atomic absorption spectrophotometry, P by molecular absorption spectrophotometry, S-SO4 (-2) by barium sulphate turbidimetry, B by Azomethin-H method, NTK by Kjeldahl method, N-NO3 (-) and N-NH4 (+) by vapor distillation with magnesium oxide and Devarda's alloy, respectively. In Fermentation of ripe coconut water there were higher consumption of K (69%), Fe (84,3%), P (97,4%), S-SO2 (-2) (64,9%), B (56,1%), N-NO3 (-) (94,7%) and N-NH4 (+) (95,2%), whereas coconut water of green fruit the most consumed ions were Na (94,5%), Mg (67,7%) and NTK (56,6%). The cultivation under agitation showed higher mineral consumption. The higher bacterial cellulose production, 6 g.L(-1), was verified in the coconut water fermentative in ripe fruit, added KH2PO4, FeSO4 and NaH2PO4 kept under agitation.