The spectroscopic studies of humic acid extracted from sediment collected at different seasons

Influence of river floods on the humification process in the bottom sediments from the Goczałkowice reservoir

“…2; Table 2). The obtained values of the g-factor are in the range of 2.0026 to 2.0031; they are typical of humic acids extracted from bottom sediments from other water reservoirs and comparable with the values of the g-factor obtained for compost (2.0031-2.0034) and sewage sludge (2.0028-2.0034) (Polak et al 2011, Polak et al 2009 [spin/g]) (Polak et al 2009). …”

“…2; Table 2). The observed increase of the g-factor may point to the elevated content of the oxygen-containing functional groups in the extracted humic acids (Polak et al 2009) and may indicate the intensifi cation of oxygen processes at the expense of aromatization processes in this part of the reservoir (Polak et al 2011). However, the concentrations of free radicals obtained for this sample indicate a decrease, which in turn points to the limitation of the oxygen processes and inhibition of humifi cation.…”

“…Thus, it may be assumed that changes caused by the fl ood wave did not infl uence the value of the g-factor for humic substances extracted from the bottom sediments. Most probably, passing of the fl ood wave caused a simultaneous increase of the intensity of oxidation processes, enrichment of humic substances in oxygen-containing functional groups (increase of g-factor), [personal elaboration, source: maps.geoportal.gov.pl] as well as aromatization processes (decrease of g-factor) (Polak et al 2011). In turn, the observed decrease of the mean values of free radical concentrations may suggest: a low content of oxygen-containing functional groups, low maturity of humic acids and a larger number of aromatic structures in the studied humic acids.…”

“…2 and 3; Table 2) may indicate lower maturity of the humic acids and higher content of the aromatic structures within them (Polak et al 2011). It seems that increase of humic acids aromatization causes the dislocation of the unpaired electrons of semiquinone radicals between the oxygen atom and aromatic carbon atoms, which in consequence leads to the decrease of the g-factor (Polak et al 2009).…”

Modulation of cytochrome P450 and induction of DNA damage in Cyprinus carpio exposed in situ to surface water treated with chlorine or alternative disinfectants in different seasons

“…Actually, physical and chemical analyses of raw lake water revealed seasonal changes with particular regard to temperature, oxygen, nitrate and phosphate concentrations. Polak et al [56] reported that the most intensive course of the humification process takes place in spring, probably due to the temperature rise as well as the growth of microbiological activity in reservoir water at this time of the year. Furthermore, free radical concentrations of HA extracted from sediments are always higher in spring than in autumn, when the highest maturity of humic acids is reached.…”