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Immune functions were examined in male rats following 28 day oral administration of formaldehyde by gastric tube at dose levels of 0, 20, 40, and 80 mg/kg. Routine parameters examined included hematology, clinical chemistry, and body, thymus, kidney, and liver weights. In addition, cellularity of spleen and lymph nodes, histology of spleen, thymus, lymph nodes, liver kidney, small and large intestines, and histochemistry of spleen and lymph nodes were evaluated. Immune parameters evaluated included serum hemagglutinin antibody response; antibody plaque forming cell response to sheep erythrocytes (lymphocyte-dependent antigen); microbicidal activity of Candida albicans; and phagocytic activity by adhesion of microspheric hydrophilic synthetic particles to leukocyte cell membrane. Body weights were slightly decreased at high dose level (80 mg/kg). The difference was significant when compared to the controls. The lymph node weights were significantly increased in rats receiving formaldehyde. The cellularity of lymphoid organs was not influenced after 28 day exposure to formaldehyde.

An optimised BCR three steps sequential extraction procedure (BCR SEP) and several single extractions with KCl, NH(4)Cl, Na(4)P(2)O(7) and 0.5 mol L(-1) HCl were used for the fractionation of Al, Cu, Fe, Mn, Pb and Zn in CRMs and in samples from a mining area with sulphidic deposits. A good interlaboratory comparability was obtained for Cu, Pb and Zn in CRM 483, CRM 701, SRM 2710 and SRM 2711 by BCR SEP. The reliability of the results obtained is also very satisfactory. Some differences were found between our results and the indicative data for Al and Fe fractionation. However, serious discrepancies were found for Mn, not only for individual steps of the fractionation, but for the data obtained overall (sum of 1-3 steps), and for the total concentration as well. Our results could be utilized as a contribution to the existing indicative values for CRM 483, SRM 2710 and SRM 2711 for interlaboratory study. Moreover, data for the fractionation of elements mentioned above for CRM 701 are first presented here.A high correlation between 0.5 mol L(-1) of HCl-extractable amounts of the elements studied, and the sum of the three steps of BCR SEP in acid sulphatic weathering products and naturally acidified soils was established, which allows us to suggest this rapid and cost-effective single extraction procedure as a valuable tool in contamination assessment.

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The work presented describes the application of different analytical approaches for study of aluminium mobility in rock, soil, and sediment samples affected by mining activity (secondary quartzites with sulfidic deposits). For this purpose we used a combination of the single extractions, the optimized BCR three-step sequential extraction procedure (SEP), and reactive aluminium determination after chelating ion-exchange on Ostsorb (Iontosorb) Salicyl by a batch technique with flame atomic absorption spectrometry quantification. The single extraction agents H(2)O, KCl, NH(4)Cl, and BaCl(2) were found to be the best for the quantitative estimation of the aluminium mobility in rocks, soils, and sediments caused by acidification of the environment. This fact was confirmed by reactive aluminium determination in the same samples. The vast majority of the aluminium content of samples after application of the optimized BCR three-step SEP is in the residues. The available fraction of aluminium extracted by dilute CH(3)COOH in the first step of this procedure correlates with the reactive aluminium content. The amounts of aluminium released in the second and the third steps and the sums from steps 1-3 of this procedure are closely associated with the aluminium content values obtained by the single dilute HCl leach. The accuracy of results obtained was verified with only informative values for individual fractions of the BCR three-step SEP because of the absence of suitable certified or standard reference materials. The amounts of the reactive aluminium determined in samples was in the range 12-82% of total soluble Al in the filtered H(2)O extracts. It was confirmed that the acidified polluted samples contain the most of reactive Al content, which is responsible for its toxicity.