Daniel Szymański, Julita Dunalska, Michał Łopata, Izabela Bigaj and Rafał Zieliński
The aim of this study was to determine the chemical composition of Lake Widryńskie bottom sediments (max. depth. 27.0 m, area 123.9 ha). The sampling of bottom sediments was conducted once, on 16 August 2010. Sampling was made in 10 specific areas. Among the 10 samples, 4 samples were taken from the littoral and sublittoral zones, while the rest were taken from the profundal zone. The dominant component of the sediments was silica and calcium carbonates were subdominant. Based on the survey, it was determined that silica occurred in greater numbers in littoral sediments, while in sublittoral sediments there was increased participation in the chemical composition of organic matter. The elements that build a capacity complex were a small percentage of the dry weight of sediment. Sediment from the vicinity of inflows contains higher amounts of silica, which confirmed the impact of the catchment on the chemical composition of sediments.
Izabela Bigaj, Michał Łopata, Julita Dunalska, Daniel Szymański and Rafał Zieliński
Sediments from hypereutrophic Lake Łajskie localized in northeastern Poland were examined on the basis of P-fraction. The sediments were collected at five sampling sites. In the investigated lake, the rank order of P-fractions was HCl-P > BD-P > NH4Cl-P > NaOH - nrP. The loosely sorbed phosphorus NH4Cl-P represented < 3% of the sedimentary inorganic phosphorus, while the reductant phosphorus (BD-P) ranged from 2 to 10%. The calcium bound phosphorus (HCl-P) showed considerable contribution (59-74%) to the sedimentary inorganic P-loads. BDP was the most reactive fraction in Lake Łajskie. Iron compounds and organic matter seem to play a significant role in regulating this labile P-budget.
Justyna Sieńska, Julita Dunalska, Michał Łopata, Katarzyna Parszuto and Renata Tandyrak
Lakes along with their surroundings are an attractive landscape component that play an important role in recreation and relaxation. In Poland, the Great Masurian Lakeland, visited by a million tourists every year, is considered to be the most attractive lake area. However, tourist pressure has several negative effects which cause degradation of the water environment. The aim of this study was to determine the trophic state of Lake Mikołajskie which is a hub for sailing and motorboating traffic. Values of the trophic status index were calculated from the content of total phosphorus, chlorophyll a and Secchi disc visibility, according to the data from the Voivodeship Inspectorate for Environmental Protection. In summer, the concentration of total phosphorus was 0.019–0.042 mg dm−3 in 2013 and 0.022–0.055 mg dm−3 in 2014. The concentration of chlorophyll a was in the range of 8.3–45.0 μg dm−3 in 2013 and 8.9–22.0 μg dm−3 in 2014. The maximum visibility of Secchi disc reached 2.0 m (2013) and 1.8 m (2014). Based on the calculated, Lake Mikołajskie can be classified as a eutrophic lake. In order to protect lakes from degradation tourists should be educated about the rational use of surface waters and the surrounding catchment. However, it is not only the massive influx of tourists, but also the activity of residents (dictated by economic reasons) that contribute to the pollution of lakes. Therefore, the development of tourism and the economy of the whole region should be harmonious and balanced so that the natural resources can serve us and future generations for as long as possible.
Rafał Zieliński, Julita Dunalska, Jolanta Grochowska, Izabela Bigaj and Daniel Szymański
The aim of this study was to compare the concentration of nitrogen and trace the dynamics of its changes in two lakes with different intensity of anthropogenic pressure. The dominant land use of Lake Paskierz catchment is built-up areas, while in Lake Sajmino, wasteland is the dominant land use. The total amount of nitrogen in Lake Paskierz ranged from 1.68 to 6.58 g Ntot m-3, while in Lake Sajmino it was from 1.03 to 1.84 g Ntot m-3. The organic fraction was a dominant form in the surface water layers of the examined lakes. A slightly different situation was found in near-bottom water layers of Lake Paskierz, where ammonium nitrogen was the dominant form in the summer stagnation. In other cases organic nitrogen was a dominant form in each of the reservoirs. Concentrations of nitrites and nitrates were low and did not affect essentially the overall amount of nitrogen in the studied lakes. Based on the results, it can be concluded that Lake Paskierz is overfertilized. The high concentrations of ammonia measured in near-bottom layers of the lake indicate that the internal supply may be a very important process affecting the trophic status. Lake Sajmino was characterized by significantly less nitrogen abundance, although the periodically increasing nitrogen concentration reveals the presence of adverse anthropopressure on the lake.
Izabela M. Bigaj, Renata Brzozowska, Michał Łopata, Grzegorz Wiśniewski, Julita A. Dunalska, Daniel Szymański and Rafał A. Zieliński
Coagulation behaviour of polyaluminium chloride (PACl) was comparatively investigated in terms of the removal of turbidity and colour with surface water. The growth of flocs was also compared. The results show that the decrease in saturation and values of dissolved oxygen was ca. 20% for ALCAT and PAX 18 at both dosages and 15% for PAX XL 19H, respectively. The floc formation growth indicated that PACl coagulation occurred not only by charge neutralization but also by a form of sweep flocculation. Besides, flocs formed by ALCAT had better sizes than the flocs formed by PAX 18 and PAX XL19H. The rate of sedimentation was stable during coagulation with higher doses, and it was dependent on the substance used.