Teresa Serra and Jordi Colomer, in collaboration with members of the Lequia research group of the Institute of the Environment of the University of Girona, publish the paper entitled “Daphnia magna filtration, swimming and mortality under ammonium, nitrite, nitrate and phosphate” in the Science of the Total Environment (STOTEN) journal.

STOTEN is an international multi-disciplinary journal for publication of original research on the total environment, which includes the atmosphere, hydrosphere, biosphere, lithosphere, and anthroposphere.

In this study, the authors point out that biological methods are a promising approach to treating wastewater in order to produce water of an appropriate quality for sub-potable water purposes, thus reducing pressure on potable water sources. Daphnia magna are organisms that filter on small suspended particles and bacteria and so may be able to clarify and disinfect wastewater. However, Daphnia magna are sensitive to common chemicals and might be vulnerable to the quality of the wastewater. This study analyses the filtration, mobility and mortality rates of Daphnia magna exposed to seven days of changing concentrations of ammonium, nitrite, nitrate and phosphate. Inactivation increased with the time of exposure for both nitrite and ammonium, with a 50% inactivation in Daphnia magna filtrations after 7 days of exposure at nitrite concentrations above 6 ppm and ammonium concentrations above 40 ppm. The Daphnia filtration remained unaltered in the nitrate and phosphate concentrations. Mortality increased with nitrite and ammonium concentrations, but not with phosphate or nitrate. The swimming velocity of Daphnia magna individuals decreased when both nitrite and ammonium concentrations increased and also with phosphate concentrations above 30 ppm. However, Daphnia magna swimming velocities remained unaltered in the presence of nitrate concentrations below 100 ppm.

This work was conducted within the framework of the Wastewater Treatment and Reuse research line, and supported by the University of Girona funding MPCUdG2016 and by the INNOQUA project from the European Union's Horizon 2020 research and innovation program (Ares(2016)1770486).