Abatement of water nutrient load in a fish culture system using the aquatic trophic levels.

Integrated aquatic systems are used to decrease the nutrient loads of effluents negating the negative environmental impacts of aquacultural systems. Some of these systems have a separate algae compartment requiring high maintenance. An integrated culture system was set up with different trophic levels: algae, zooplankton, and fish. The algal tank was in-line with the fish and zooplankton components to minimize the maintenance required for the algae. A control flow-through system was also set up without the algae and zooplankton compartments. The systems were run for 6 weeks, and water temperature, pH, dissolved oxygen, NO3 , NO2 , NH4 , and PO4 concentrations were measured. A removal rate was determined for each water parameter and the densities of the algae and zooplankton species were measured in each compartment of the integrated system. The concentrations of most nutrients in the integrated system were similar to those of the control system. The density of algae increased during the first 3 weeks and remained almost stable until the end of the experiment. There was an inverse relationship between the densities of two zooplankton suggesting compensatory effects on the control of the algal bloom. The integrated system improved water quality with minimal algal culture maintenance, water exchange, and no fish mortality. PRACTITIONER POINTS: An integrated system could effectively reduce the nutrient load of water. Water replacement in the integrated system was significantly lower than that of a flow through system. The inline plankton culture tanks decreased greatly the maintenance of the system.

Copper Bioaccumulation Kinetics in Swan Mussel, Anodonta cygnea (Linnaeus, 1758) During Waterborne Exposure to CuO Nanoparticles.

This study was conducted to investigate bioaccumulation of copper in two internal organs (mantle and foot) of swan mussel, Anodonta cygnea (Linnaeus, 1758) in exposure to copper oxide nanoparticles (CuO NPs). Basal concentration of Cu in the mantle (3.15 ± 1.09 µg g-1 DW) was significantly (p < 0.05) lower than the foot (5.43 ± 1.54 µg g-1 DW). At the end of the exposure period, the highest concentration of Cu in both organs belonged to the highest exposure concentration. Calculated bioconcentration factor (BCF) values showed significant (p < 0.05) higher values for the mantle in each day and each exposure concentration (except the lowest exposure concentration) than the foot. For both organs, the highest and lowest BCFs occurred at the lowest and highest exposure concentrations, respectively. Cu concentration in both organs was significantly (p < 0.05) decreased after day 4. Based on the results, it was obvious that exposure to sub-lethal concentrations of CuO NPs would lead to the significant accumulation of copper in mantle and foot that may have adverse effects on this organism.