Quantification of Microplastics in Plagioscion squamosissimus Sold in the Macapá Metropolitan Area, at the Mouth of the Amazon River, Brazil

The Amazonian Coastal Zone is characterized by high biodiversity and significant socioeconomic importance, particularly in terms of fishing and the fish trade, which may be affected by the presence of anthropogenic solid waste. Despite the importance of this resource to the region, information on the occurrence and quantification of microplastics in Plagioscion squamosissimus (Amazon hake or corvina) a species frequently sold at open-air markets in the region remains limited. In this context, this study aimed to quantify microplastics in specimens of P. squamosissimus sold in the municipalities of Macapá, Santana, and Mazagão. A total of 30 specimens were analyzed, with 10 purchased from open-air markets in each municipality; the stomach, intestine, and gills were examined. The specimens were digested with potassium hydroxide (KOH) solution, filtered through cellulose paper, and examined microscopically. The data were analyzed using descriptive statistics, a normality test, one-way ANOVA, and Welch’s ANOVA. Microplastics were detected in all samples, Particles with characteristics of microplastics were detected in all specimens, with statistically significant differences among municipalities in the number of particles identified in the intestine, gills, and stomach, with higher mean values in Macapá. The results demonstrate the occurrence of microplastic-like particles in fish sold in the region and reinforce the importance of environmental monitoring.