Coarse particulate matter (PM10) concentrations and chemical composition were monitored from 2014 to 2017 at three sampling sites in the Metropolitan Region of Rio de Janeiro, namely Botafogo, Gávea, and Gericinó. All sites are located close to the 2016 Olympic Game arenas. The average annual PM10 concentrations were above the limits recommended by the World Health Organization (WHO) at all sampling sites. Of all the analyzed water-soluble ions, the highest concentrations were obtained for NO3-, SO42-, Cl- and Na+. Sulfate displayed a higher anthropic contribution (ca. 70%). Iron and copper were present in all samples, originated from soil resuspension and traffic (fuels and brakes, among others). Overall, civil works to restructure the city and the construction of the Olympic Game arenas increased PM10 and some of its constituent levels prior to 2016. After the Olympic Games, PM10 concentrations have decreased, due to governmental policies regarding traffic planning and civil work finalization.

This study aimed to evaluate the distribution of mercury in rats after controlled chronic exposure to three different doses of HgCl2 for 30 days. Samples of blood, brain, liver, testis, heart, and kidneys were collected for mercury determination. Although the rats were exposed to different doses, the Hg levels in blood were similar among the groups under study. However, the distribution of mercury in the organs have substantially differed between low and high doses. There was a significant tendency to high deposition in the liver and kidney. The deposition profile in the tissues suggests that the level of mercury remains relatively low in blood while it is deposited at preferential sites such as liver and kidney, demonstrating that, at least at the doses studied, the screening for Hg exposure is unreliable by blood sample analysis.

É proposto um sistema de análise química por injeção em fluxo para a deteminação espectrofotométrica de manganês em aços baseado no efeito catalítico da Ag(I) na oxidação em linha de Mn(II) a Mn(VII) sobre uma superfície eletródica de platina. Após a injeção simultânea de amostra e eletrólito na célula eletroquímica, a mistura era homogeneizada por bolhas de ar e os íons permanganatos gerados eram monitorados a 545 nm. As alturas dos sinais transientes obtidos refletiam a concentração do manganês na amostra. Foram investigados os principais parâmetros relacionados com os processos coulométricos tais como intensidade de corrente, concentração do mediador, tempo de eletrólise, natureza do eletrólito suporte, bem como aqueles relacionados com a arquitetura do sistema FIA. O sistema espectrofotométrico proposto possibilitou a determinação de manganês em aços no intervalo de concentrações de 5,00 a 150 mg L-1 (r = 0,9998). Com tempos de eletrólise de 60 s, foram possíveis 20 determinações por hora (R.S.D. < 3%). Os resultados da análise aços certificados com o sistema proposto não foram estatisticamente diferentes dos valores certificados e daqueles obtidos pelo método de referência ao nível de 95% de confiabilidade.

The aim of this work is to propose a flow spectrophotometric procedure for manganese determination in steel based on electrochemical oxidation of Mn(II) to Mn(VII) at a Pt electrode surface by means of the catalytic effect of Ag(I). The on-line oxidation step was obtained by injecting sample and electrolyte solution directly into an electrolytic cell. After electrolysis, the injectate was homogenized by bubbling air. The permanganate ions produced were passed through the spectrophotometer where absorbance was monitored at 545 nm. Effects of direct current, silver concentration, timing, flow rates, concentration and composition of support electrolyte were investigated. Direct current and silver content manifested themselves as the most relevant parameters. For determination of manganese in the 5.00 - 150 mg L-1 range (r = 0,9998) and 60 s electrolysis time, the sample throughput was 20 h-1. Accuracy was assessed by analyzing ten steel standard reference materials. Results are precise (R.S.D. < 3%) and in agreement with certified values of reference materials and with standard methods at 95% confidence level.