Microplastics in fish meal: Contamination level analyzed by polymer type, including polyester (PET), polyolefins, and...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Marine Biology

Background:

• Fish meal (FM) is a key protein source in aquaculture and animal farming.
• Microplastics (MPs) are pervasive in marine environments and can enter the food chain.
• Existing analytical methods are insufficient for quantifying synthetic polymers in FM.

Purpose of the Study:

• To develop and validate a procedure for quantifying microplastic contamination in fish meal.
• To determine the levels of specific polymers (polyolefins, polystyrene, PET) in fish meal.

Main Methods:

• A multi-step procedure involving solvent extractions and hydrolytic treatments.
• Selective depolymerization was used for poly(ethylene terephthalate) (PET) quantification.
• Gravimetric and SEC-UV techniques were employed for polyolefins and polystyrene (PS).

Main Results:

• Accurate quantification of PET microplastics in FM at 12.9 mg/kg (dry mass).
• Polyolefin and PS concentrations were estimated below 100 mg/kg, limited by matrix interference and sensitivity.
• Pyrolysis-GC/MS suggested as a method to improve sensitivity for PS and polyolefins.

Conclusions:

• The developed method enables accurate quantification of PET microplastics in fish meal.
• Further advancements are needed to improve sensitivity for other polymer types in FM.
• Understanding microplastic contamination in FM is crucial for food safety and environmental monitoring.