Wpływ procesów biochemicznych i substancji humusowych na stężenie związków wapnia i magnezu w wodach

The results of laboratory tests showed that biochemical oxidation, as well as concomitant biocoagulation phenomena, brought about a change of the calcium and magnesium concentration in the water. This led to the establishment of a new calcium-magnesium equilibrium in the humic substances, which were present in the water. As a result, calcium concentration in the investigated water samples underwent some variations (but not substantial changes). The said processes exerted an indirect effect on the concentration of magnesium. When following addition of a sewage portion the value of the Ca/Mg molar ratio fell below that of the Ca-Mg equilibrium in the humic substances, the concentration of magnesium decreased in the course of biochemical degradation. When the Ca/Mg ratio value exceeded the Ca-Mg equilibrium value, magnesium concentration increased. The decrement or increment of magnesium was BOD5-dependent and averaged 0.045 val/gO2. Statistical analysis of the relationship between calcium and magnesium concentration variations for 8 rivers and 24 cross-sections substantiated the results of laboratory tests. Over 92% of instances showed a positive annual [Mg] = f([Ca]/[Mg]) relation with a coefficient of determination greater than 0.6. A positive annual [Ca] = f([Ca]/[Mg]) relation was detected in 6% of instances.