Eight trace elements were determined in 20 Brazilian brands of grape juice, distributed over the country. Highest measured concentrations (As: 0.016; Cd: 0.010; Cr: 0.060; Cu: 1.28; Ni: 0.032; Pb: 0.016; Sb: 0.0040 and Zn: 1.44 mg L-1) comply with Brazilian maximal tolerance levels for inorganic contaminants (As: 0.5; Cd: 0.5; Cr: 0.1; Cu: 30; Ni: 3; Pb: 0.4; Sb: 1 and Zn: 25 mg L-1). Determination of arsenic species has shown inorganic As(V) as predominant in most samples. Sodium concentrations, nowadays a major public health concern, were also measured, showing an average of 149 mg L-1. Analytical results for this element were much higher than label concentrations, showing the need for better quality control.

Abstract The total litter production and its stock on the soil in the Maciço da Pedra Branca (RJ) were monitored for one year. The forest litter produced was 7,533 kg.ha-1.yr-1 and the litter layer was 7,300 kg.ha-1. In the former, the heavy metal concentration ranged from 0.08 mg.kg-1 for Cd to 35.2 mg.kg-1 for Zn. In the litter layer, the concentration was 1.3 times higher, on average. The renewal rates for the stock of these metals in the litter layer varied from 0.2 year for Cr to 1.9 years for Cd and Pb. The results found were higher than those found in similar studies, due to the proximity to the metropolis of Rio de Janeiro.

Resumo A produção e o estoque de serapilheira no Maciço da Pedra Branca (RJ) foram monitorados por um ano. A serapilheira produzida foi 7.533 kg.ha-1.ano-1; a estocada sobre o solo foi 7.364 kg.ha-1. Na primeira, a concentração dos metais variou de 0,08 mg.kg-1 para Cd a 35,2 mg.kg-1 para Zn e na estocada sobre o solo, a concentração foi em média 1,6 vezes maior. Os tempos de renovação do estoque destes metais na serapilheira variaram de 0,2 ano para Cr a 1,9 anos para Cd e Pb. Os resultados encontrados foram superiores a estudos semelhantes, sendo atribuídos à proximidade da metrópole circundante.

Results on the optimization of analytical methods for the determination of phosphorus in phosphino-polycarboxylate (PPCA), used frequently as scale inhibitor during oil production, by ICP-AES and ICP-MS are presented. Due to the complex matrix of production waters (brines) and their high concentration in inorganic phosphorus, the separation of organic phosphorus prior to its determination is necessary. In this work, minicolumns of silica immobilized C18 were used. Optimization of the separation step resulted in the following working conditions: (1) prewashing of the column with methanol (80% v/v); (2) use of a flow rate of 5 mL/min and 10 mL/min, respectively, for the preconditioning step and for percolation of the water sample; (3) final elution of organic phosphorus with 7 mL of buffer of H3BO3/NaOH (0.05 M, pH 9) with a flow rate of 1 mL/min. Sample detection limits (3s) for different combinations of nebulizers and spectrometric methods, based on 10 mL water aliquots, are: ICP-AES -Cross flow (47 mg/L) and Ultrasonic (18 mug/L); ICP-MS -Cross flow (1.2 mug/L), Cyclonic (0.7 mug/L) and Ultrasonic (0.5 mug/L). Typical recoveries of organic phosphorus are between 90 and 95% and the repeatability of the whole procedure is better than 10%. The developed methodology was applied successfully to samples from the oil-well NA 46, platform PNA 2, Campos basin, Brazil. Assessment of the PPCA inhibitor was possible at lower concentrations than achieved by current analytical methods, resulting in benefits such as reduced cost of chemicals, postponed oil production and lower environmental impacts.