Avaliação comparativa dos efeitos ecotoxicológicos de glitter convencional e biodegradável sobre o microcrustáceo de água doce Ceriodaphnia dubia Richard, 1894.

Abstract

Plastic pollution is a significant global threat to the health of ecosystems, given the ubiquity and high persistence of these materials in the environment. Among primary microplastics, glitter stands out as an emerging contaminant, composed of a polyethylene terephthalate (PET) core and metallic layers, which enters water bodies primarily through domestic and industrial effluents. In addition to being resistant to degradation, it can obstruct the digestive and filtering systems of many organisms and act as a vector for leachable chemicals. As an alternative, “bioglitters” (based on mica, cellulose, or modified starch) have emerged, though their environmental risks, associated with pigments and minerals, still require further investigation. Considering this and considering the role of zooplankton as a trophic link and bioindicator of environmental quality, this study compared the acute ecotoxicological effects of conventional glitter and bioglitter on the microcrustacean Ceriodaphnia dubia Richard, 1894. Acute toxicity tests (24 h and 48 h) were conducted to determine the LC50 of each material, supplemented by micro-Fourier transform infrared spectroscopy (micro-FTIR) analysis to characterize the chemical composition of conventional glitter and bioglitter. Conventional glitter (PET) had LC50 values of 1.97 g/L (24 h) and 0.607 g/L (48 h), while bioglitter (mica/agar) exhibited higher values of 2.48 g/L (24 h) and 2.153 g/L (48 h), indicating lower relative acute toxicity. Micro-FTIR analysis confirmed the polymeric nature of conventional glitter and the mineral/organic basis of bioglitter, physicochemical properties that directly influenced interaction with the organisms. The primary mechanism of toxicity identified was physical in nature: conventional glitter caused intense particle adhesion, obstructing structures and drastically reducing the organisms’ mobility, while bioglitter formed fewer adhesive aggregates, preserving their locomotion. The results indicate that, although bioglitter represents a less harmful alternative to conventional glitter, it is not risk-free at high concentrations, since both materials exhibited significant ecotoxicological effects on C. dubia. These findings reinforce the need to expand specific ecotoxicological studies on these emerging contaminants. Furthermore, it is important to note that chronic exposure studies are essential for a more comprehensive understanding of the impacts of these materials on essential biological functions, such as reproduction and growth