RESUMO
Dietary arsenic intake estimates based on surveys of total arsenic concentrations appear to be dominated by intake of the relatively non-toxic, organic arsenic forms found in seafood. Concentrations of inorganic arsenic in food have not been not well characterized. Accurate dietary intake estimates for inorganic arsenic are needed to support studies of arsenic's status as an essential nutrient, and to establish background levels of exposure to inorganic arsenic. In the market basket survey reported here, 40 commodities anticipated to provide at least 90% of dietary inorganic arsenic intake were identified. Four samples of each commodity were collected. Total arsenic was analysed using an NaOH digestion and inductively coupled plasma-mass spectrometry. Separate aliquots were analysed for arsenic species using an HCl digestion and hydride atomic absorption spectroscopy. Consistent with earlier studies, total arsenic concentrations (all concentrations reported as elemental arsenic per tissue wet weight) were highest in the seafoods sampled (ranging from 160 ng/g in freshwater fish to 2360 ng/g in saltwater fish). In contrast, average inorganic arsenic in seafood ranged from less than 1 ng/g to 2 ng/g. The highest inorganic arsenic values were found in raw rice (74 ng/g), followed by flour (11 ng/g), grape juice (9 ng/g) and cooked spinach (6 ng/g). Thus, grains and produce are expected to be significant contributors to dietary inorganic arsenic intake.
Assuntos
Arsênio/análise , Análise de Alimentos , Dieta , Farinha/análise , Ácido Clorídrico , Espectrometria de Massas , Oryza/química , Rosales/química , Alimentos Marinhos/análise , Hidróxido de Sódio , Espectrofotometria Atômica , Spinacia oleracea/química , Estados UnidosRESUMO
We measured physical working capacity at a heart rate of 170 bpm (PWC170) and diffusing capacity for carbon monoxide (DLCO) in two groups of children ranging in age from 9 to 17 years. One group was formed of highly trained competitive swimmers and the other of age, sex and size matched untrained counterparts. Bicycle ergometry was used to establish PWC170. The DLCO was measured at rest (DLCO rest) and while pedalling at 170 bpm (DLCO ex). The PWC 170, DLCO rest and DLCO ex were significantly higher in swimmers than in non-swimmers. Repeated measurements in the same subjects show that individual increases in DLCO rest and DLCO ex were result of both growth and training.