Impact assessment of some heavy metals on tilapia fish, Oreochromis niloticus, in Burullus Lake, Egypt

Abstract Background Burullus Lake has received a great attention because of its environmental and economic importance for being a significant source of fish production in Egypt. It is subjected to many of environmental changes due to the huge amount of discharges originated from different sources as well as many human activities. The Nile tilapia (Oreochromis niloticus) is an abundant sedentary fish present in the most Egyptian lakes, Nile River, and ponds. The study was designed to evaluate some metal pollution in Burullus Lake. Results The values of heavy metals (Mn, Zn, Fe, Ni, Cu, and Pb) were measured in lake water and muscles of O. niloticus fish during winter and summer 2014. Water samples were collected from six sampling sites, while fish samples were collected from the three sectors (eastern, middle, and western) of the lake. The mean values of heavy metals (Mn, Zn, Fe, Ni, Cu, and Pb) in surface water of Burullus Lake during winter and summer for the year 2014 were 1.09, 10.50, 29.38, 6.87, 2.05, and 5.98 μg/L, respectively, whereas the annual means of heavy metals (Mn, Zn, Fe, Ni, Cu, and Pb) in the muscles of O. niloticus fish were 0.68, 4.70, 10.62, 0.52, 0.39, and 0.46 μg/g wet wt., respectively. Conclusions In lake water, Mn was the lowest concentration of the six sampling sites, while Fe was the highest concentration, whereas in fish muscles, Cu recorded the lowest concentration of the three sectors, while Fe was the highest concentration. The southern part of Burullus Lake had the highest heavy metal values as it influenced by the discharge of massive amounts of domestic sewage as well as agricultural and industrial effluents. The accumulation of heavy metals in fish muscles of the three sectors showed different patterns. Generally, the values of metals in the fish muscles were accepted by the international legislation limits and are safe for human consumption

Removal of cadmium from aqueous solution using marine green algae, Ulva lactuca

The present study aimed to evaluate the efficiency of marine algae for removal of metals from the aqueous solution. The green alga, Ulva lactuca, collected from the intertidal zone of the Suez Bay, northern part of the Red Sea was used to reduce cadmium levels from the aqueous solutions. The biosorption mechanisms of Cd2+ ions onto the algal tissues were examined using various analytical techniques: Fourier-transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM). Results indicated that at the optimum pH value of 5.5; about 0.1 g of U. lactuca was enough to remove 99.2% of 10 mg L−1 Cd2+ at 30 °C in the aqueous solutions. The equilibrium data were well fitted with the Langmuir and Freundlich isotherms. The monolayer adsorption capacity was 29.1 mg g−1. The calculated RL and ‘n’ values have proved the favorability of cadmium adsorption onto U. lactuca. The desorption test revealed that HCl was the best for the elution of metals from the tested alga. In conclusion, the seaweed U. lactuca was the favorable alternative of cadmium removal from water

The Oxygenic Photogranule Process for Aeration-Free Wastewater Treatment

This study presents the oxygenic photogranule (OPG) process, a light-driven process for wastewater treatment, developed based on photogranulation of filamentous cyanobacteria, nonphototrophic bacteria, and microalgae. Unlike other biogranular processes requiring airlift or upflow-based mixing, the OPG process was operated in stirred-tank reactors without aeration. Reactors were seeded with hydrostatically grown photogranules and operated in a sequencing-batch mode for five months to treat wastewater. The new reactor biomass propagated with progression of photogranulation under periodic light/dark cycles. Due to effective biomass separation from water, the system was operated with short settling time (10 min) with effective decoupling of hydraulic and solids retention times (0.75 d vs 21–42 d). During quasi-steady state, the diameter of the OPGs ranged between 0.1 and 4.5 mm. The reactors produced effluents with average total chemical oxygen demand less than 30 mg/L. Nitrogen removal (28–71%) was achieved by bioassimilation and nitrification/denitrification pathways. Oxygen needed for the oxidation of organic matter and nitrification was produced by OPGs at a rate of 12.6 ± 2.4 mg O₂/g biomass-h. The OPG system presents a new biogranule process, which can potentially use simple mixing and natural light to treat wastewater