Chemical risk assessment of fish fed with aquatic plants from wastewater phytoremediation using monte carlo simulation

Valorizing macrophyte biomass as animal feed represents a promising circular economy strategy, yet its safety remains uncertain. To address this, the present study explicitly evaluates the human health risks associated with consuming Nile Tilapia (Oreochromis niloticus) fed with Azolla spp. biomass cultivated during a 10-day phytoremediation period in swine wastewater rich in copper (Cu) and zinc (Zn). This study addresses this issue through a Quantitative Chemical Risk Assessment (QCRA) supported by Monte Carlo Simulation. Results indicate that Zn poses no significant risk to adults or children, whereas Cu presents a considerable concern, particularly for children and under 16 h light conditions. Sensitivity analysis identifies plant metal concentration and fish developmental weight as the main risk drivers. The model demonstrates that the risk is manageable rather than prohibitive: a controlled 15-day supplementation period effectively reduces Cu hazards up to sixfold in adults and 12-fold in children. Safety is therefore dependent on biomass supplementation duration, offering a practical route to safely incorporate phytoremediation biomass into aquaculture. This study establishes the first quantitative framework for assessing and managing metal transfer risks, transforming a theoretical circular economy concept into a viable and evidence-based practice for sustainable aquaculture systems.