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Toksyczność osadów ściekowych z oczyszczalni ścieków

Raclawska H., Doskarova S., Skrobankova H.

Inżynieria Mineralna

2011

R. 12, nr 1

39-50

Tematem artykułu jest określenie przyczyn toksyczności ścieków. Toksyczność badano na rozwielitkach Daphnia magna oraz algach Desmodesmus subspicatus. Dla zmniejszenia toksyczności, do wartości określonej przez ustawę nr 294/2005 Coll., do ekstraktu wodnego dodano różne sorbenty (aktywny węgiel i amberlit - XAD - niejonowy absorbent polimerowy). Ustalono, że mętność wody spowodowana dodaniem aktywnego węgla wpływa na zachowanie Desmodesmus subspicatus. Koncentracja składników odżywczych uwolnionych ze ścieków oraz przez obecność zanieczyszczeń (PAH, AOX i metale ciężkie) także wpływa na zachowanie alg. Dodatek aktywnego węgla zmniejszył koncentrację PAH poniżej limitu, co jest niebezpieczne dla Daphnia magna, ale zmniejszenie zawartości składników szkodliwych w wodzie nie było wystarczające. Nie osiągnięto granicznych wartości EC50 dla Pb, Zn i Cu określonych w literaturze.

Article is oriented on the cause of sludge ecotoxicity. The ecotoxicity was studied on Daphnia magna and algae Desmodesmus subspicatus. For decreasing of water extract exotoxicity to the limit value required by Decree No.294/2005 Coll. the addition of different sorbent (active carbon and Amberlite – XAD nonionic polymeric absorbent) were observed. The behaviour of Desmodesmus subspicatus is influenced by turbidity of water extract after adding of aktive carbon, concentration of nutrients releasing from sludge and also by presence of pollutants (PAHs, AOXs and heavy metals). The addion of activated carbon decrease the concentration of PAHs below the limit which is hazardous for Daphnia magna, but the decreasing of hazardous elements in water extract was not sufficient. The limit value EC50 published in literature for Pb, Zn and Cu was not reached.

Daphnia: model herbivore, predator and prey

Lampert Winfried

Polish Journal of Ecology

2006

Vol. 54, nr 4

607-620

In the past 30 years, Daphnia has become a model organism in aquatic ecology. I review the changing concepts and paradigms in plankton ecology as reflected in the work on Daphnia. The availability of radiotracers favoured a new physiological approach that resulted in better energetic models and more reliable estimates of filtering rates. This led to deeper insights into the role of herbivore grazing on phytoplankton and microbial communities, and nutrient recycling. It provided a conceptual basis for general hypotheses on predictable seasonal successions (e.g. the PEG model). On the other hand, increasing knowledge about selective predation on zooplankton triggered population dynamic models and gave explanations for changing community structures. The Size-Efficiency-Hypothesis generated a framework for studies on trade-offs between competitive ability and susceptibility to predation. Daphnia was now in the centre of interaction-based concepts, being predator and prey at the same time. It was the backbone of practical applications of the theory in food-web manipulations. When ultimate factors came into the focus, Daphnia played an important role in explaining striking phenomena like diel vertical migration and cyclomorphosis. Its central position in food-webs, the unique propagation mode, easy cultivation and accessibility by molecular genetic methods made it a favourite object for studies in evolutionary ecology, concerning local adaptation, evolution of defences and life histories, induced phenotypic change, and genetic diversity. The large advantage of Daphnia over other biological model organisms is that its importance in pelagic freshwater systems is undoubtedly known. Hence there is a direct way of applying the results to ecological systems.