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The agricultural use of peatlands, the stabilization of the substrate for building or road construction or for increasing the capacity of soil to support heavy machinery for industrial activities (peat and petroleum extraction), harvesting to provide peat for energy, and the growing media and initiation of chemical processes must be preceded by drainage. As a consequence of drainage, peat underwent an irreversible conversion into moorsh (secondary transformation of the peat). The object of the study was to investigate comparatively the organic matter composition and molecular structure of humic acids (HAs) in the raised bog, fen, and peat-moorsh soils developed in various compositions of botanical cover, peat-forming species, and oxic and anoxic conditions as a result of the oscillation of ground water during drainage as well as to evaluate the vulnerability of soil organic matter (SOM) to decomposition. Drainage was shown to be the principal factor causing the various chemical compositions and physicochemical properties of HAs. Large and significant differences in chemical composition of peat and the properties of HAs were found to be related to the degree of decomposition. The HAs from drained peatlands were less chemically mature. In contrast, the HAs from fen and raised bog were found to be more mature than that of the corresponding drained peatlands. The above findings showed the distinguishable structure of HAs within the soil profile created by the plant residue biodegradation and formed in both oxic and anoxic conditions. The analytical methods of thermal analysis together with the optical densities and paramagnetic behaviour are suitable and effective tools for studying structure–property relationships characterizing the origin and formation process of HAs in various environmental conditions.

Objective To evaluate the influence of 1.1% amino acid dialysis solution (AADS) on parameters of nutrition in continuous ambulatory peritoneal dialysis (CAPD) patients. Study Design Studies were performed in 8 men, using AADS for the overnight exchange. Before starting AADS, food intake, nutritional status, and laboratory indices were evaluated and compared to the respective parameters obtained after 3 and 6 months of treatment with AADS, as well as after 3 months of AADS withdrawal. With the start of AADS, doses of antacids were increased and modified during AADS administration; the modified doses were continued through 3 months after cessation of AADS. Another group of CAPD patients using standard dialysis solutions served as controls. In these patients the same parameters were evaluated four times at 3-month intervals. Results Administration of AADS resulted in: (1) 91% absorption of amino acids and improvement of serum amino acid pattern; (2) no change in nutritional intake during the treatment, but after the 3 months of AADS therapy, levels of nutrient intake were lower than those 3 months after withdrawal of AADS with correction of metabolic acidosis; (3) no change in indices of nutritional status, but 3 months after AADS discontinuation, total body weight, lean body mass, and body mass index were significantly higher than those shown after 3 months of treatment; (4) an increase in hemoglobin concentration, hematocrit, BUN, and blood H+. The examined parameters were not significantly changed in patients treated for 9 months with standard dialysis solutions exclusively. The values of nitrogen balance obtained during AADS administration and after 3 months of AADS withdrawal were significantly higher than those obtained in the respective periods in the control group. The blood pH, pCO2, and HCO3– in the last period of the study were higher in the AADS group than in the control group. Conclusion In relatively well-nourished CAPD patients, overnight AADS administration results in increased serum concentration of amino acids without changes in other nutritional parameters. The use of AADS should be associated with increased doses of antacid medication, which abolishes the metabolic effects of acidosis that develop during AADS administration and facilitates positive nitrogen balance.

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