Contamination by Microplastics in Free-Living White-Eared Opossums (Didelphis Albiventris) Resident in Campo Grande, Mato Grosso Do Sul – Brazil

Abstract This study aimed to investigate the presence of microplastics in the gastrointestinal tract and lungs of white-eared opossums ( Didelphis albiventris ), as well as their effects on these organs and body condition of sampled animals. We captured 22 opossums from April to December 2023 in six forest fragments of Campo Grande, capital of Mato Grosso do Sul state. The estimate of body condition was performed using measurements of weight and head-body length for males and females. Stomach, ileum, and lung fragments were collected during necropsies for histopathological study and detection of microplastics by alkaline digestion with KOH. Digested samples were vacuum filtered using filter paper and dried in an oven. The dried filters were examined under an optical microscope. A total of 270 microplastics were detected in the 22 animals examined. The ileum presented the highest number of microplastics (n = 141), fibers were the most common type (n = 185), and blue was the predominant color (n = 140). Regarding chemical composition, the most frequently detected microplastics were polyvinyl chloride, polyethylene terephthalate, and acrylonitrile butadiene styrene. Although all D. albiventris presented microplastics in their evaluable tissues, no effects on body condition or tissue damage were observed. Since D. albiventris are common animals in Campo Grande and are contaminated by microplastics, these animals can act as sentinels of environmental condition.