Morphochemical characterization and interactions of secondary microplastics with paracetamol and microalgae

The morphochemical properties of microplastics influence their interactions with pollutants, biota, and toxicity. This study focused on the effects of microalgae exposure to secondary microplastics (SMP) derived from different plastic materials, often associated with pharmaceutical residues. Tetraselmis sp. were exposed to SMP alone and in combination with paracetamol. The SMP exhibited irregular morphology and sizes ranging from 8 to 1749 µm. morphochemical properties were analyzed using FTIR, SEM-EDS, and zeta potential. FTIR analysis identified three types of SMP (linear low-density polyethylene, polypropylene, and polystyrene), all showing a negative surface charge. Carbon, oxygen, calcium, chlorine, aluminum, bromine, and titanium were detected in all samples. Microalgae growth remained unaffected by SMP exposure, except at paracetamol concentrations of 400 and 500 mg.L-1. The study suggests that the surface charge of SMPs significantly influences their toxicological effects. Furthermore, the resilience of microalgae to paracetamol and microplastics underscores their potential as bioindicators in microplastic-contaminated environments. Keywords: morphochemical properties, paracetamol, secondary microplastic, Tetraselmis sp., toxicity interactions.