Toxicity of polystyrene nanoplastic and copper oxide nanoparticle in Artemia salina: Single and combined effects on stress responses

Nanoparticles, such as copper oxide nanoparticle (CuO NP) and polystyrene nanoplastic (PSNP), are increasingly released into aquatic environments, and pose potential risks to aquatic animals such as brine shrimps. Understanding the toxicity of these nanoparticles, especially when combined, is very important to assess their environmental effects. Therefore, this work describes the toxicity of polystyrene nanoplastic (PSNP) and CuO nanoparticles (CuO NPs) for brine shrimp (Artemia salina). The body length and stress biomarkers, including the activity of SOD, CAT, GST, Acid phosphatase, AChE, level of MDA and GSH, and expression of the hsp70 gene were quantified. The 48h-EC50 values for PSNP, CuO NPs, and their combination were determined as 1.024 and 5.089, and 0.512 mg L⁻¹, respectively. The combined exposure groups showed the highest growth inhibition. This was associated with increased activity of SOD and GST, decreased activity of CAT, a significant decrease in the level of GSH, a significant increase in the MDA level, and expression of the hsp70 gene (P < 0.05). Moreover, an increased ACP and reduced AChE activity were observed in exposure groups. This study indicated that PSNP and CuO NPs have synergistic toxicity for A. salina, underscoring the importance of further investigation into their combined effect on aquatic animals.