Organ-Specific Distribution and Morphological Characterization of Microplastics in Tor putitora (Golden Mahseer) from...

Microplastics (MPs) are emerging pollutants posing ecological and physiological threats to aquatic organisms. This study investigates the organ-specific distribution and morphological characteristics of MPs in Tor putitora (Golden Mahseer) collected from Bhimtal Lake, Ladhiya River (Chalthi), and Pancheshwar (confluence of the Kali and Saryu rivers) in Uttarakhand, India, from November 2024 to April 2025. Thirty specimens from each site were analyzed for MP contamination in the gill, gastrointestinal tract (GIT), and muscle tissues using digestion with KOH and microscopic identification. Particle identification was based on visual and morphological criteria, and polymer confirmation by FTIR or Raman spectroscopy was not performed. Functional groups were categorized by morphology, color, and size. The gastrointestinal tract (GIT) exhibited the highest MP abundance (mean ± SD = 5.53 ± 4.26 items/individual), followed by gills (3.50 ± 2.58) and muscle (0.08 ± 0.02). Fibers were the dominant morphology (49.6%), followed by fragments (27.9%) and pellets (22.5%). Black and blue particles accounted for over 74.4% of all MPs, while most particles (71.3%) were ≤ 500 µm. Significant variation ([Formula: see text]) among organs suggests that both respiratory and dietary exposure routes are involved. The predominance of fibers and small-sized MPs suggests possible influence from textile, domestic, and fishing-related activities. These findings highlight the need for organ-level assessments in comprehending the bioaccumulation of MPs in Himalayan freshwater fish.