Abstract The article presents a novel, practical, sustainable and multi-purpose conceptual method for urban lakes water treatment. It is based on the separation of the inflowing water from the lake's main body with an impermeable barrier and a construction of enhanced littoral zone. The impermeable barrier alongside the shoreline creates a new littoral zone between the land and the lake water. Inflowing water as well as nutrient-rich seepage water from a direct catchment will be pretreated in a specially constructed biotic and abiotic zones. The naturally formed community of macrophytes in the littoral zone ensures biological pretreatment. The remaining phosphorus load will be eliminated in the abiotic part of the system composed of natural, cost-efficient and easily accessible sorption material. Based on nutrients budget calculated for a few urban lakes, we estimate that the diversion of the main nutrient-rich river inflow and the cutoff of the littoral zone will reduce a load of nitrogen and phosphorus by more than 80% and 90% respectively.

Abstract We explored the shell shape and growth performance of the soft-shell clam Mya arenaria L. in two shallow brackish water estuaries of the southern Baltic Sea – Darss-Zingst and Ruegen lagoons. Observed clams ranged from 2 to 50.1 mm in length with detected age up to 6 years old. The growth patterns of the clams were analyzed using the von Bertalanffy growth function (VBGF). An isometric relationship was found between shell length and shell height or shell thickness. Asymptotic length and weight were predicted according to von Bertalanffy equation as L∞ = 82.75 mm and W∞ = 10.9 g. The relationship of wet weight to length was allometric, with exponent b = 3.09. Observed shell lengths were close to values predicted by the model. Our study distinguished patterns of the molluscan growth in estuarine transitional environment of the southern Baltic Sea in comparison with other coastal habitats with pronounced spatial environmental heterogeneity.

Abstract One of the most important phenomena, from the point of view of sustainable development of the countryside, is the worsening quality and diminishing quantity of water resources. The agriculture-induced pressure on ecosystems tends to increase while hunger and malnutrition of global population grows, expected to reach 2 billion persons by 2050. Moreover, there is no more land that could be utilized for this purpose. Widespread appearance of erosion, pollution of ground and surface waters and shortages of water resources is therefore expected. This seeks for an urgent need for a new approach to environmental management. For this purpose, not only technical measures, but also natural mechanisms, involving physical and biological processes must be used. This paper presents the results of investigations carried out in Wielkopolska (Poland) and in the Gumera (Gumara) catchment (Ethiopia) on climate and land use changes, and their impacts on water quantity and quality. Possibilities to counteract the worsening of water conditions are presented. Long-term investigations show that proper shaping of landscape structures, mainly by creation of shelterbelts, strips of meadows, land-water ecotones and small water bodies, and improving soil structure by increasing organic matter content, is one of the best tools for achieving this goal.

Abstract The dynamics of nutrients in water passing through the forest floors of two plantation forests (Cupressus lusitanica and Eucalyptus globulus) and an adjacent natural forest were monitored over a one year period at Munesa, Ethiopia. The results showed that, in all forest types, after K, Ca and Cl were the most abundant nutrients leached from the forest floor to the mineral soil. The concentration of N03−N in the natural forest was about 10 times higher than that of NH4−N, but 8 and 3 times higher than that of NH4−N under Eucalyptus and Cupressus, respectively. No significant differences in concentrations of most of the nutrients were observed among forest types, but magnesium and N03−N were significantly higher under the natural forest and Eucalyptus than under Cupressus. Except for NH4−N, which was depleted in relation to throughfall in the natural forest, the concentrations of all other nutrients were enriched in litter leachate in relation to both rainfall and throughfall. However, with the exceptions of NO3−N in all forest types, Ca under Cupressus and PO4−P under Cupressus and Eucalyptus, all measured nutrient fluxes from the forest floor to the mineral soil decreased in relation to throughfall fluxes. Generally, the results show that despite the differences in tree species composition among the forest types the organic layer acted as a sink for most of the nutrients coming via throughfall.

Abstract This study introduced the spatial pattern of PCDD, PCDF and dl-PCB concentration in the sediments of Ethiopian small river-lake system. Among the analyzed samples the highest contamination was observed in the lake littoral (222.11 ng kg−1 d.w.). The lowest concentration was noted at the outflow from the lake (26.65 ng kg−1 d.w.). The WHO-TEQ concentrations showed decreasing trend along the river-lake system with highest value in the inflow (2.32 ng TEQkg−1 d.w.) and the lowest at the outflow (0.55 ng TEQ kg−1 d.w.). The concentration of PCDD, PCDF and dl-PCB in the lake causes diseases among local population and prevents of use of water resources except from the outflow. Moreover the lake persistence and its ecosystem services provided for the local community were endangered by erosion of land and nutrient load from pastoral landscape, which could generate toxic algal blooms. For reversing the lake pollution the ecohydrological systemic solutions which integrated methodology to prevent all those threats to sustainable water and ecosystems was designed and implemented.

Abstract Lake Starodworskie is a reservoir restored since the 1960s, first through artificial aeration and in the 1990s by the method of phosphorus inactivation. Studies of zooplankton were conducted in 2007–2008. The aim of the present research was to analyze and evaluate the taxonomic structure and overall abundance of the crustacean plankton of the lake. The eudominant species found were: Bosmina longirostris and Daphnia cucullata , while the dominant species included: Eudiaptomus graciloides, Diaphanosoma brachyurum and Mesocyclops leuckarti . The average annual density of Crustacea in the reservoir amounted to 329 indiv. dm −3 , while the average biomass reached 5.1 mg dm −3 . The abundance of indicatory species typical for eutrophic waters was smaller than recorded during previous zooplankton studies of Lake Starodworskie (average densities were: M. leuckarti – 12 indiv dm −3 , T. oithonoides – 4 indiv dm −3 , D. brachyurum – 14 indiv dm −3 , B. longirostris – 92 indiv dm −3 ). The overall abundance of the zooplank ton and its structure suggest moderate eutrophy of the reservoir.

Abstract The main purpose of the study was to assess a new sewage sludge composting validation method based on the survival of indicator microorganisms ( Escherichia coli, Salmonella senftenberg W775, streptococci group D) introduced into composting piles. The experiment was carried out during summer and winter seasons. The piles were aerated mechanically by turning. The results obtained in the summer cycle showed that the time needed for the total inactivation of the indicatory bacteria in samples from three layers of the pile (top, middle, bottom) did not exceed 9 days. In winter the elimination of the indicatory microorganisms was longer and lasted from 29 days in the center of the pile to 60 days at the bottom layer. The implemented method for the estimation of sludge composting hygienization effectiveness is very useful and contributes to minimizing soil and ground water contamination.

Abstract For decades an area of 4 500 ha of Ner River valley was used as a part of Łodź municipality wastewater treatment system. Sandy alluvial soils were irrigated with nutrient rich river water for high hay crop production. Nowadays wastewater treatment plant in Łodź discharges 2 m3s−1 of wastewater and produces daily 30–35 t of dry matter of sludge which can be utilized in the valley for energy biomass production. Of a great importance for sustainable development is the recirculation of nutrients between urban and rural areas. Reuse nutrient rich wastewater and sludge results in saving natural resources (mining rocks, forest wood) and protection of receiving water bodies.