Testing and optimizing methodologies for microplastic extraction from owl pellets

Microplastic pollution is a pressing global environmental concern, potentially threatening ecosystems and entering the food chain. Owls, as nocturnal carnivorous birds, are at significant risk of ingesting microplastics due to their diverse foraging habits. This study aimed to identify the most suitable procedure for extracting microplastics from owl pellets, focusing on efficiency, functionality, and cost and ensuring the extraction of both prey and microplastics without damage. Experiments were conducted on pellets from long-eared owl (Asio otus) collected from three different habitats in Ankara, Türkiye. The extraction of microplastics was then tested using various treatments (n = 25), involving different durations, temperatures, and chemicals. A total of 100 pellet samples were utilized with three replicates for each treatment. The study identified three different methods particularly effective for microplastic extraction: using 10% sodium hydroxide (NaOH) solution at 55 °C for 75 min, using 10% potassium hydroxide (KOH) at 55 °C for 75 min, or using Fenton reagent (30% H2 O2 + FeSO4) at 50 °C. Additionally, immersing the pellets in a 60 °C water bath for 10 min improved the sorting of prey items. Overall, the most effective approach for extracting microplastics considering the balance of time, cost, and effort was using 10% KOH solution at 55 °C for 75 min.