Fate and health implications of polycyclic aromatic hydrocarbons in a sustainable food waste recycling system using housefly maggots and Nile tilapia

This study aimed to investigate the transformation, bioaccumulation, and human and ecological health risks of polycyclic aromatic hydrocarbons (PAHs) in a food waste culture system that included housefly maggots (Musca domestica) and Nile tilapia (Oreochromis niloticus). Feeding trials were carried out in 25 groups of maggots under different breeding densities (2.50, 5.00, 7.50, 10.0, and 12.5 g/kg), using a well-mixed culture medium with measured proportions of rice waste (RW) and meat and vegetable waste after pretreatment (A-MVW) (rinsing and draining). The ratio of RW to A-MVW was 100:0, 75:25, 50:50, 25:75, and 0:100 %. The results showed that the ∑PAHs contents in housefly maggots fed with food waste ranged 22.5–232 μg/kg ww, with the percentage of high molecular weight PAHs being 86.2 ± 12.4 %, with carcinogenic PAHs accounting for 24.3–93.5 %. Based on the PAHs content and growth indexes of the maggots, the optimal conditions were a breeding density of 10.0–12.5 g/kg and food waste substrate of 75 %–100 % A-MVW. The lowest PAHs content was 22.5–28.4 μg/kg, the highest yield 136–172 g/kg, the highest content of crude protein 49.2 %–56.6 %, and the highest content of crude lipid 19.8 %–20.7 %. Concentrations of ∑PAHs (20.3 ± 5.30 μg/kg ww) in residues from waste converted by housefly maggots were not significantly different among different treatment groups (p > 0.05). It was determined that there is no potential ecological risk from PAHs if the residues are utilized as organic fertilizers in agricultural production. There was no significant difference between the concentration of PAHs (12.3 ± 1.78 μg/kg ww) in the tilapia fed with the three maggot feeds and the control diet (p > 0.05). The human health risk assessment showed that the PAHs of tilapia fed housefly maggots did not pose a health risk to consumers. Therefore, housefly maggots cultured from food waste can be used as high-quality and safe protein feed sources for tilapia cultivation. Copyright © 2025 Elsevier.