Maria Cristina Duran

Arsenic exposure assessment of children living in a lead mining area in Southeastern Brazil

Environmental contamination by arsenic compounds in the Ribeira River Valley, São Paulo, Brazil has already been observed. Lead mining and refining activities had been carried on since late colonial times and finished recently, at the end of 1995. The source of As in the region is known to be mainly from arsenopirite geological presence in the lead ore. Chronic exposure to arsenic compounds may cause peripheral vascular disorders, hyperpigmentation, hiperkeratosis and cancer of the skin, bladder, lung, liver and other internal organs. The purpose of this study was to assess children exposure to arsenic from environmental sources in the region. Urine samples from children between 7 to 14 years old were collected at the following localities: Cerro Azul (Paraná); urban areas of Ribeira (São Paulo) and Adrianópolis (Paraná); Vila Mota neighborhood (rural area of Adrianópolis) and Serra neighborhood (Iporanga, São Paulo), identified as groups 1, 2, 3 and 4, respectively. Group 1 was considered as non-exposed control group. Toxicologically relevant forms of As were determined by atomic absorption spectrometry with hydride generation system. The median values of urine arsenic levels obtained in groups 1, 2, 3 and 4 were respectively: 3.60, 6.30, 6.41 e 8.94 microg/L.

Monitoramento da autenticidade de amostras de bebidas alcoólicas enviadas ao Instituto Adolfo Lutz em São Paulo

Este trabalho teve como objetivo verificar a autenticidade de bebidas alcoolicas (whisky, vodka, conhaque de gengibre, etc.) enviadas para analise ao Instituto Adolfo Lutz no periodo de 1993 a agosto de 1999. Devido a presenca no mercado nacional de bebidas alcoolicas clandestinas, principalmente aquelas com alto valor agregado, foi realizado o monitoramento atraves da analise de composicao quimica destas bebidas. Normalmente estes produtos sao elaborados com alcool, agua, aroma e corante caramelo e que por falta de controle dessas materias-primas, podem oferecer risco potencial a saude humana pela presenca de metanol. A tecnica empregada na analise dos componentes secundarios e metanol das amostras foi realizada atraves da cromatografia em fase gasosa com detector de ionizacao de chama. Observou-se que em 608 amostras de bebidas alcoolicas analisadas, 391 eram falsificadas e dentre estas 2 apresentaram teores de metanol acima do limite tolerado (200mg/100mL de alcool anidro) pela legislacao em vigor. Os resultados obtidos sugerem uma grande persistencia em se produzir bebidas alcoolicas falsificadas. Desta forma, e muito importante estar sempre monitorando estes produtos e identificando os diferentes tipos de falsificacoes existentes no pais.

Validação e aplicação de metodologia analítica na determinação de nutrientes inorgânicos em arroz polido

A method of partial digestion of raw milled rice (Oryza sativa) was validated for the determination of inorganic nutrients (Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn) by inductively coupled plasma optical emission spectrometry. Based on hydrolysis with HCl, the method is simple and relatively fast, presenting satisfactory characteristics of performance. This method was used in the preparation of 40 raw milled rice samples commercialized in the state of Sao Paulo, Brazil. Emission spectrometry was applied to determine the mean contents and standard deviations of Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn (in mg.100 g -1 rice), which were 4.31 ± 0.44, 0.22 ± 0.10, 0.32 ± 0.08, 58.0 ± 15.0, 26.1 ± 5.7, 1.06 ± 0.26, 1.78 ± 0.55, 92.1 ± 15.2, and 1.24 ± 0.18, respectively. These results were compared with seven food composition tables available in the literature, which revealed discrepancies for Ca, Fe, Na, and K. Our data were also used to estimate the contribution of Ca, Cu, Fe, Mg, Mn, P and Zn contained in daily rice consumption to the Recommended Daily Intake (RDI). It was found that rice contributes significantly to the RDI, especially of Mn, Cu, and Zn, particularly in view of the average daily consumption of rice per person in Brazil.

Comparação de diferentes métodos estatísticos utilizados para avaliar o desempenho de participantes em um programa de ensaio de proficiência

Five statistical approaches were applied for assessing the performance of participants in 19 rounds (2007-2011) of the Proficiency Testing Program for lead in blood determination (PEP-Pbs), conducted by Instituto Adolfo Lutz. The performance evaluation was provided by using the z-score. The following statistical approaches were tested: 1 – mean and standard deviation, after rejecting outliers; 2 – median and normalized inter-quartile range; 3 – robust mean and robust standard deviation; 4 – robust mean and standard deviation for proficiency assessment of 3 μg/100 mL (for concentrations up to 40 μg/100 mL and a standard deviation for proficiency assessment of 7.5 % of the assigned value (for concentrations above 40 μg/100 mL); 5 – robust mean and standard deviation for proficiency assessment of 2 μg/100 mL (for concentration up to 40 μg/100 mL) or 5 % of the assigned value (for concentrations above 40 μg/100 mL). The approach 4 showed to be the most adequate statistical methodology to assess the performance of participating laboratories in the PEP-Pbs.Five statistical approaches were applied for assessing the performance of participants in 19 rounds (2007-2011) of the Proficiency Testing Program for lead in blood determination (PEP-Pbs), conducted by Instituto Adolfo Lutz. The performance evaluation was provided by using the z-score. The following statistical approaches were tested: 1 – mean and standard deviation, after rejecting outliers; 2 – median and normalized inter-quartile range; 3 – robust mean and robust standard deviation; 4 – robust mean and standard deviation for proficiency assessment of 3 μg/100 mL (for concentrations up to 40 μg/100 mL and a standard deviation for proficiency assessment of 7.5 % of the assigned value (for concentrations above 40 μg/100 mL); 5 – robust mean and standard deviation for proficiency assessment of 2 μg/100 mL (for concentration up to 40 μg/100 mL) or 5 % of the assigned value (for concentrations above 40 μg/100 mL). The approach 4 showed to be the most adequate statistical methodology to assess the performance of participating laboratories in the PEP-Pbs.

Emprego de planilhas eletrônicas, baseadas nas normas ISO e recomendações IUPAC, em curvas analíticas da análise de água

This paper describes the development and validation of the electronic spreadsheet in Microsoft Excel® software for evaluating the analytical quality of calibration graphs of linear and homoscedastic functions, used in water physical-chemical analysis by UV-Vis spectrophotometry, and obtained according to ISO standards and IUPAC guidelines. By introducing the absorbance data, the spreadsheet shows the calibration (with respective function) and the residues graphs, and also computes the residual standard deviation, angular coefficient standard deviation, interception standard deviation, and coefficient of determination R2. On prediction terms, the spreadsheets calculate (confidence level at 95 %): the prediction interval (showing the respective curve with upper and lower limits), the absorbance critical value, the concentration critical value (xC), the minimum detectable value of concentration (xD) or detection limit, the quantification limit, and the confidence intervals for samples. From the initial spreadsheet, simplifications were introduced and the new spreadsheets were used for analyzing nitrate, nitrite and iron. The effect of the simplifications on the parameters calculation, and the correlations between xC/xD ISO 11843-1,2 parameters and the CCα(decision limit)/CCβ(detection capability) European Commission parameters, were discussed. Keywords. analytical quality control, analytical curves, water analysis, electronic spreadsheets.