José Paulo Santos

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Measurements made in feces and urine of Wistar rats exposed to lead acetate (n = 20) in drinking water since the fetal period were compared with those obtained from a control group (n = 20) in order to assess the age influence on Pb excretion. The measurements were made in different collections of rats aging between 1 and 11 months. To determine the Pb content of the samples, total reflection X-ray fluorescence (TXRF) and electrothermal atomic absorption spectrometry (ETAAS) were used for the urine samples and energy dispersive X-ray fluorescence (EDXRF) was used for the feces.The results show high concentrations of Pb being eliminated from the organism by urine and feces in contaminated rats. Values vary from (600`140)mgl1 to (5 460`115)mgl1 in urine and from (4 500`300)mgg1 to (11 400`3 300)mgg1 in dry feces. The control rats show, in general, low lead concentrations or below detection limits. The fecal/urinary ratio was studied. It was shown to be about three to four orders of magnitude and positively correlated with time. It was verified in feces and urine that excretion decreases with the animal age and that this decrease is made by different levels of excretion. The excretions of Pb in urine and in feces are positively correlated.A good agreement was found between the results obtained with TXRF and ETAAS for urine samples. This work also stresses the suitability of these techniques in the study of Pb intoxication.

The concentration of lead in liver and kidneys of Wistar rats, fed with lead since fetal period in relation to their age and to a control group, was determined. A group of rats was exposed to lead acetate (n=30) in drinking water and the other group was exposed to normal water (n=20). Samples were collected from rats aging between 1 and 11 months and were analyzed by Energy Dispersive X-ray Fluorescence (EDXRF) without any chemical preparation. The EDXRF results were assessed by the PIXE (Proton Induced X-ray Emission) technique. The formaldehyde used to preserve the samples was also analyzed by ETAAS (Electro-Thermal Atomic Absorption Spectrometry) in order to verify if there was any loss of lead from the samples to the formaldehyde. We found that the loss was not significant (<2%). Concerning the mean values of the lead concentration measured in the contaminated soft tissues, in liver they range from 6 to 22μgg(-1), and in kidneys from 44 to 79μgg(-1). The control rats show, in general, values below the EDXRF detection limit (2μgg(-1)). The ratio kidney/liver ranges from 2 to 10 and is strongly positively correlated with the age of the animals. A Spearman correlation matrix to investigate the correlation between elemental concentrations and the dependence of these concentrations with age showed that there is a strong positive correlation with age for lead in the liver but not in the kidney. The correlation matrix showed also that the concentration of lead in these two soft tissues is not correlated. The lead accumulation in liver is made by different plateaus that strongly decrease with age. It was verified the existence of two levels of accumulation in kidney, not very highlighted, which might be indicative of a maximum accumulation level for lead in kidney.

The concentration of lead in liver and kidneys of Wistar rats, fed with lead since fetal period in relation to their age and to a control group, was determined. A group of rats was exposed to lead acetate (n=30) in drinking water and the other group was exposed to normal water (n=20). Samples were collected from rats aging between 1 and 11 months and were analyzed by Energy Dispersive X-ray Fluorescence (EDXRF) without any chemical preparation. The EDXRF results were assessed by the PIXE (Proton Induced X-ray Emission) technique. The formaldehyde used to preserve the samples was also analyzed by ETAAS (Electro-Thermal Atomic Absorption Spectrometry) in order to verify if there was any loss of lead from the samples to the formaldehyde. We found that the loss was not significant (<2%). Concerning the mean values of the lead concentration measured in the contaminated soft tissues, in liver they range from 6 to 22μgg(-1), and in kidneys from 44 to 79μgg(-1). The control rats show, in general, values below the EDXRF detection limit (2μgg(-1)). The ratio kidney/liver ranges from 2 to 10 and is strongly positively correlated with the age of the animals. A Spearman correlation matrix to investigate the correlation between elemental concentrations and the dependence of these concentrations with age showed that there is a strong positive correlation with age for lead in the liver but not in the kidney. The correlation matrix showed also that the concentration of lead in these two soft tissues is not correlated. The lead accumulation in liver is made by different plateaus that strongly decrease with age. It was verified the existence of two levels of accumulation in kidney, not very highlighted, which might be indicative of a maximum accumulation level for lead in kidney.

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