*3.4. Interactions of BDE-47 and Nickel in P. tricornutum*

The toxicity mechanisms of nickel and BDE-47 on *P. tricornutum* cells are not yet fully understood. Consequently, the potential interactions of nickel and BDE-47 were evaluated using concentration addition (CA) and independent addition (IA) models with the MIXTOX tool [33]. The two pollutants' EC50-72h values for nickel, BDE-47, and mixtures were used to evaluate the interaction patterns. The *a* value was identified as −4.5, indicating that the interaction between nickel and BDE-47 was synergistic rather than antagonistic concerning *P. tricornutum* toxicity.
