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Hair is good bioindicator of exposure, due to its ability to store and retain trace elements for long periods of time. But it can be especially useful when hair dyes are used since they may contain potentially toxic salts in their composition. In this context, analytical methods for the determination of bismuth, cadmium, lead, and silver in scalp human hair by electrothermal atomic absorption spectrometry were successfully validated. A total of 60 samples obtained from women between 18 and 60 years were analyzed: 34 dyed hairs and 26 untreated hairs (control). Average results expressed in dry weight (dyed/control) for each element were 2.34/0.49 µg g-1 (silver), 0.142/0.139 µg g-1 (bismuth), 0.055/0.054 µg g-1 (cadmium), and 2.09/0.99 µg g-1 (lead), respectively. These results agreed with those previously reported for non-exposed populations. A statistically significant higher Ag concentration in dyed hairs was observed, suggesting the bioaccumulation of this element. The associations between metal concentration and variables of interest (age, education, smoking habit, dye brand, use of dietary supplements) were investigated. A strong Pearson correlation was found for the pair Ag/Pb (r = 0.494, p < 0.05). Also, strong associations between lead levels and all the selected variables were observed (p < 0.05), while strong associations between silver levels with age and dye brand and association between cadmium levels and smoking habit were found. Furthermore, several commercial hair dye brands were analyzed to verify compliance with cosmetic regulations. This constitutes the first study of such characteristics performed in Uruguay, with worldwide relevance.

RESUMO

Resumen Con el objetivo de medir la influencia que ejercen las actividades mineras de la explotación del carbón sobre la calidad del aire en las comunidades ubicadas en el área de influencia al norte de Colombia, se realizó una medición de los niveles de los metales pesados Cu, Cd, V y Pb en 21 muestras de agua lluvia. Este estudio se realizó por periodo de un año, mediante espectrometría de absorción atómica electrométrica. El promedio de las concentraciones de los metales fueron: Cu 23,47 ± 13,97 µg/L, Cd 4,72 ± 3,29 µg/L y V 11,25 ± 6,75 µg/L. Los resultados sugieren que la atmósfera no se encuentra contaminada por Pb, pero las actividades mineras (las excavaciones y voladuras, la combustión de combustibles fósiles, de crudos de petróleo y gasoil, las fuentes de tráfico vehicular, etc.) afectan significativamente la presencia y los niveles de los demás metales incluidos en el estudio. La contaminación en la zona influye en que el agua lluvia no cumpla con las normas de calidad, tanto a nivel nacional como internacional, ya que los parámetros de pH y Cd superan los límites permisibles y por tanto no es apta para el consumo humano.

Abstract To measure the influence of coal mining activities on air quality in northern Colombia, a first approach was made to assess pollution by measuring the levels of the heavy metals Cu, Cd, V, and Pb in 21 samples of rainfall over a one year period, by the electrothermal atomic absorption spectrometry technique. The average concentrations of metals in the study area in wet precipitation were: Cu 23.47 ± 13.97 µg/L, Cd4.72 ± 3.29 µg/L y V 11.25 ± 6.75 µg/L. The results suggest that the atmosphere is not polluted by Pb, but mining activities (excavation and blasting, combustion of fossil fuels, crude oil and gas oil, and vehicular traffic sources) may significantly affect the presence and the levels of the other studied metals. Contamination in the area makes rain water infringe the quality standards, both nationally and internationally, since the parameters of pH and Cd exceed the permissible limits, therefore it is not suitable for human consumption.

Resumo A fim de medir a influência que exercem as atividades de mineração de carvão sobre a qualidade do ar nas comunidades localizadas na área de influência ao norte da Colômbia, foram medidos os níveis de metais pesados Cu, Cd, V e Pb em 21 amostras de água da chuva. Este estudo foi feito ao longo de um ano, mediante espectrometria de absorção atômica eletrométrica. As concentrações médias dos metais foram: Cu 23,47 ± 13,97 µg/L, Cd 4,72 ± 3,29 µg/L e V 11,25 ± 6,75 µg/L. Os resultados sugerem que a atmosfera não está contaminada por Pb, mas as atividades de mineração (escavação e detonação, a queima de combustíveis fósseis, petróleo bruto e diesel, e o tráfego de veículos) afetam significativamente a presença e os níveis dos outros metais incluídos no estudo. A poluição faz que a água da chuva não atenda aos padrões de qualidade, tanto a nível nacional como internacional, posto que os parâmetros de pH e Cd excedem os limites admissíveis e, portanto, fazem que à água seja imprópria para consumo humano.

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The present work proposed an analytical method for the direct determination of chromium in infant formulas employing the high-resolution continuum source electrothermal atomic absorption spectrometry combined with the solid sample analysis (SS-HR-CS ET AAS). Sample masses up to 2.0mg were directly weighted on a solid sampling platform and introduced into the graphite tube. In order to minimize the formation of carbonaceous residues and to improve the contact of the modifier solution with the solid sample, a volume of 10 µL of a solution containing 6% (v/v) H2O2, 20% (v/v) ethanol and 1% (v/v) HNO3 was added. The pyrolysis and atomization temperatures established were 1600 and 2400 °C, respectively, using magnesium as chemical modifier. The calibration technique was evaluated by comparing the slopes of calibration curves established using aqueous and solid standards. This test revealed that chromium can be determined employing the external calibration technique using aqueous standards. Under these conditions, the method developed allows the direct determination of chromium with limit of quantification of 11.5 ng g(-1), precision expressed as relative standard deviation (RSD) in the range of 4.0-17.9% (n=3) and a characteristic mass of 1.2 pg of chromium. The accuracy was confirmed by analysis of a certified reference material of tomato leaves furnished by National Institute of Standards and Technology. The method proposed was applied for the determination of chromium in five different infant formula samples. The chromium content found varied in the range of 33.9-58.1 ng g(-1) (n=3). These samples were also analyzed employing ICP-MS. A statistical test demonstrated that there is no significant difference between the results found by two methods. The chromium concentrations achieved are lower than the maximum limit permissible for chromium in foods by Brazilian Legislation.

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RESUMO

Arsenic is an element widely present in nature. Additionally, it may be found as different species in several matrices and therefore it is one of the target elements in chemical speciation. Although the number of studies in terrestrial plants is low, compared to matrices such as fish or urine, this number is raising due to the fact that this type of matrix are closely related to the human food chain. In speciation analysis, sample preparation is a critical step and several extraction procedures present drawbacks. In this review, papers dealing with extraction procedures, analytical methods, and studies of species conservation in plants cultivated in terrestrial environment are critically discussed. Analytical procedures based on extractions using water or diluted acid solutions associated with HPLC-ICP-MS are good alternatives, owing to their versatility and sensitivity, even though less expensive strategies are shown as feasible choices.

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