Synergetic Effect of Polynuclear Hydroxyl-aluminium and Coexisting Zinc on the Survival of Aquatic Diatom

Attached algae are one of the main constituents in a river ecosystem since they are the primary producer and serve as food for aquatic insects and fishes. Therefore, their preservation is important for river environment. In this study, the effect of metals on the decay of Nizschia palea, diatom, was investigated by batch experiments. Polynuclear hydroxyl-Al (Al-b) at the concentration of 0.3 mg/l and Zn higher than 0.2 mg/L accelerated the decay of N. palea, while Ca higher than 10 mg/ L meditated the toxicity of Al-b. Zn and Al-b had an additive or synergetic action on the decay of N. palea at the concentrations of higher than 0.1 mg/L and 0.03 mg/L, respectively. This suggests that combined effect of metals should be considered for river environments and establishing water quality standard for aquatic biota.