CONCENTRATION OF URANIUM IN WATERS OF THE BIGGEST LAKES OF THE TYWA RIVER DRAINAGE BASIN

The paper presents the results of research of uranium concentrations in its different kinds – suspended and dissolved – in waters of the largest lakes located in the catchment area of the River Tywa – Strzeszowskie Lake, Dłużyna Lake, Długie Lake and Dłuzec Lake. Small (or the order of several 0,01 µg/l) variations in concentration of uranium in different lakes were noted. The study has also shown a seasonal variation – in a similar range – in concentrations of the above species of uranium, as well as total uranium. The content of dissolved uranium was highest in the autumn and winter, lower in the spring and summer. Overall, total uranium was found in greatest concentrations during the fall, in other seasons concentrations were lower and similar to each other. Suspended uranium was found in largest concentrations in autumn and summer, in lower ones in spring and winter. Concentrations of the different species of uranium during the study period showed a small variation – variation coefficient below 10% for total uranium and dissolved uranium, and about 25% for suspended uranium. The observed concentrations of uranium were typical of uncontaminated unpolluted water

Macroelements in the surface microlayer of water of urban ponds

Analyses were conducted concerning the accumulation of four metals representing the group of macroelements, i.e. sodium, potassium, calcium and magnesium in two ponds located in the city of Słupsk. Water samples for chemical analyses were collected from the surface microlayer using a Garrett net. At the same time subsurface water samples were collected. Concentrations of metals were determined using a mass spectrometer. Generally, amounts of sodium, potassium, calcium and magnesium were similar in surface microlayer and subsurface water. Only in the case of potassium and calcium was low enrichment observed in the surface microlayer in one pond, while the greatest extent for magnesium enrichment was observed in the spring period

THE INFLUENCE OF THE CONTENT OF ALUMINIUM ON THE BIOCENOSIS OF THE WATERS OF LAKES WITH POORLY URBANIZED RECEPTION BASINS

The article presents the research results of the content of aluminium in the waters of the largest lakes situated in the reception basin of the Tywa river. The general content of aluminium and its form: dissolved and non-dissolved was examined. The general content of aluminium in those waters varied from 5.3 to 98.9 μg/l, while the content of dissolved aluminium varied from 3.0 to 57.0 and its non-dissolved form from 1.0 to 54.0 μg/l. The average concentration of the content of aluminium in the waters of examined lakes was similar; Dłużec lake – 42.9, Strzeszowskie lake – 39.2, Dołgie lake 45.7, Swobnickie lake 41.4 μg/l. The prevailing form of aluminium in the examined bodies of water was the dissolved form. The greatest amounts of that metal in waters of the examined lakes were present in autumn and spring, and the smallest amounts in summer and winter, the tendency concerned the entire content of aluminium and its non-dissolved form. The dissolved form of aluminium in the waters of examined lakes was present in the largest amounts in winter (on average – 17.4 μg/l), in the smallest amounts in spring (14.0 μg/l), this seasonal diversity – was weakly marked. The existing concentration of aluminium is typical of non-polluted surface waters, and with the stated reaction and the content of sulfurs, carbonates and chlorides in the examined waters, they were not toxic to the biocenosis

Anthropogenic pressure on the largest lakes of the River Tywa catchment

The largest lakes of the River Tywa basin i.e. Strzeszowskie, Dołgie, Swobnica and Dłużec (north-west Poland, West Pomeranian Lakeland) were studied in the period 2008–2013, usually in a six week cycle. The aim of the study was to determine the degree of anthropogenic pressure on the lakes. Anthropogenic pressure was assessed against the natural vulnerability of lakes to degradation and the actual rate of eutrophication, with particular consideration of the catchment areas. Catchments of the studied lakes were classified as III class – catchment with moderate possibility of matter supply to lakes. Lakes Swobnica and Dłużec are characterised by low resistance to degradation. Lake Strzeszowskie is categorised as having moderate resistance and Lake Dołgie is non-resistant to degradation and highly susceptible to external pressure. The rate of eutrophication of lakes Strzeszowskie and Dłużec was found to be moderate, whereas lakes Dołgie and Swobnica show a high rate of eutrophication. The analysis of nutrient loading reaching the waters of the aforementioned lakes shows that the main area source is arable land, and the fundamental point source is the inflow of river waters to each of the analysed reservoirs. Nutrient loading supplied by the river is several times higher than area load. Such conditions require protective action to be taken within the catchment area and particularly, intensive implementation of good agricultural practice. In the studied lakes, there is a significant predominance of incoming nutrient loadings over dangerous and admissible loads

ECOLOGICAL STATE OF THE STEPNICA RIVER (WESTERN POMERANIA)

The article describes the research results of the hydro-morphological and hydro-chemical elements of the Stepnica river (Western Pomerania). The research has been carried out on four positions situated in its upper course, where the river is highly transformed and susceptible to anthropogenic factors. It has been indicated that in most places the Stepnica river has got low quality of waters in terms of hydromorphology as well as hydrochemistry

BOTTOM SEDIMENTS AS AN ELEMENT OF THE KRĄPIEL RIVER ECOSYSTEM

Research on the structure of sediments was carried out in 2015 in the river Krąpiel and its tributaries. The main objectives of this study were to classify the types of sediments with grain size analyzing according three different criteria, as well as influence of the substrate on the abundance and diversity of macrobenthic organisms, and to determine the quality of the ground for natural breeding of salmonids. It was found that according to Polish standards, bottom sediments of the Krąpiel river and its tributaries belong to the coarse – gravel type or sandy – gravel type, whereas according to the method used in Anglo-Saxon countries – these are sandy sediments. It was also shown that the grain size of bottom sediments of the Krąpiel river and its tributaries determine friendly living environment for macroinvertebrates and for breeding salmonids

THE INFLUENCE OF THE CONTENT OF ALUMINIUM ON THE BIOCENOSIS OF THE WATERS OF LAKES WITH POORLY URBANIZED RECEPTION BASINS

The article presents the research results of the content of aluminium in the waters of the largest lakes situated in the reception basin of the Tywa river. The general content of aluminium and its form: dissolved and non-dissolved was examined. The general content of aluminium in those waters varied from 5.3 to 98.9 μg/l, while the content of dissolved aluminium varied from 3.0 to 57.0 and its non-dissolved form from 1.0 to 54.0 μg/l. The average concentration of the content of aluminium in the waters of examined lakes was similar; Dłużec lake – 42.9, Strzeszowskie lake – 39.2, Dołgie lake 45.7, Swobnickie lake 41.4 μg/l. The prevailing form of aluminium in the examined bodies of water was the dissolved form. The greatest amounts of that metal in waters of the examined lakes were present in autumn and spring, and the smallest amounts in summer and winter, the tendency concerned the entire content of aluminium and its non-dissolved form. The dissolved form of aluminium in the waters of examined lakes was present in the largest amounts in winter (on average – 17.4 μg/l), in the smallest amounts in spring (14.0 μg/l), this seasonal diversity – was weakly marked. The existing concentration of aluminium is typical of non-polluted surface waters, and with the stated reaction and the content of sulfurs, carbonates and chlorides in the examined waters, they were not toxic to the biocenosis

Abiotic factors as a long-term stressor for the vendace fisheries in Lake Ińsko (European Central Plains Ecoregion, Poland)

The population of vendace (Coregonus albula L., 1758) in many European lakes, especially in Central Europe, have declined recently as a result of lake eutrophication. The aim of the study was to (i) determine many years’ changes in the volume of vendace catches and specific physicochemical parameters of water, (ii) determine correlations between particular physicochemical parameters, and (iii) indicate hydrochemical parameters which show the greatest impact on the volume of vendace catches on the example of Lake Ińsko located in the European Central Plains Ecoregion. Principal Component Analysis (PCA) was applied to indicate the most important hydrochemical variables impact on vendace fisheries. Among them, after redundancy analysis, 6 were taken into account (total nitrogen, N-NO3, N-NO2, total phosphorus, oxygen concentration, temperature). Time series analysis revealed an increasing trend in nutrients concentration in lake. Analyses showed that fish catches were mostly negatively connected to nitrogen and phosphorus concentration. Trend analysis, based on the above-mentioned parameters, can provide prediction of vendace catches for further years with the predictability at the level of around 60% accuracy. The results of this study are very crucial to the vendace fisheries and for formulating fisheries management policies in the future in the changing hydrochemical condition of lakes

Long term changes in the quality and water trophy of Lake Ińsko - the effect of the re-oligotrophication?

In 1970-2010, during the period of spring circulation and summer stagnation, hydrochemical studies were conducted in Lake Ińsko (Western Pomeranian Lake Region, Poland) with determination of the lake susceptibility to degradation and trophic changes. Also, the effect of the catchment area on the water quality in this waterbody was assessed. The waters of the study lake were characterised by low static index, which is an additional indicator of low dynamics of water masses, and low susceptibility to degradation. In spite of this, significant changes in the lake quality and trophy were observed. The hydrochemical parameters defining water quality of the study lake continued to improve. In the 70’s, the water quality was at the border of class II and III, while in 2006 and 2010 it reached the level characteristic for class I waters. Moreover, in the 70’s and 80’s of the previous century, Lake Ińsko Duże was a mesotrophic lake. Then, an increase in the lake trophy was observed, resulting in signs of eutrophy. At the end of the 90’s and in the first decade of the 21st century, the study lake returned to the state of mesotrophy. No restoration works were undertaken in Lake Ińsko in the study period. The improvement in water quality, called oligotrophication, resulted most probably from the lake reaction to changes in the soil use in the catchment area, since fewer phosphorus and nitrogen compounds flow into the lake, and also from the regulation of the wastewater management in the town of Ińsko