Effect of different shapes of Nano-CuO and humic acid on two-generations of Daphnia Magna.

Nanomaterials (NMs) have significant technological advantages due to their unique properties but their release into the environment also carry potential eco-toxicological risks. CuO NMs have numerous industrial and commercial applications, however less is known about the risks to human health and ecosystems. This study investigated different shapes of nano-CuO (cubic and octahedron) with humic acid (HA: 2 mg/L and 10 mg/L) on the reproduction, growth, survival rate and Cu accumulation in the two-generations of Daphnia Magna species. Nano-CuO cubic and octahedron shapes were analyzed by SEM, demonstrating {111} and {100} facets. The results indicated that octahedron has the more evident toxic effect than cubic shape for both generations. Continuous exposure to nano-CuO exhibited negative effects on body length, cumulative neonates and Cu accumulation in filial generation F (1). Survival rate of CuO octahedron was the least 66%, while CuO cubic was 73% for parental generation F (0). In addition, HA showed a significant reduction in the toxicity of nano-CuO for both generations, leading to an enhanced survival rate, body length and reproduction. This study provides insights of the long-term effect of different shapes of nano-CuO in the existence of humic acid to the multi-generations ecosystem.