Di-Ammonium Phosphate-Triggered Toxicity and its Effect on the Morphology and Behavior of Catla catla Fingerlings Under Controlled Laboratory Settings

Abstract

Contamination of freshwater bodies by fertilisers is a significant issue due to their toxicity, persistence, and potential for bioaccumulation. This study focuses on the acute toxicity of diammonium phosphate (DAP) to the freshwater fish species Catla catla. This research aimed to understand the connection between mortality rates and the abnormal behavioural and morphological changes observed in Catla catla when exposed to cadmium chloride. Static bioassay tests were conducted to determine the LC50 value of diammonium phosphate (DAP) for Catla catla, as well as to observe behavioural responses and morphological alterations. After treating the fish with various concentrations of diammonium phosphate (DAP) over different exposure periods, the percentage of mortality was recorded. The lowest concentration of DAP that resulted in mortality was found to be 2 mg/l. The first death among the experimental fish was noted at a concentration of 4 mg/l after 24 hours of exposure. Following 96 hours, the LC50 value for diammonium phosphate (DAP) was determined to be 4.48 mg/l. Key behavioural changes observed during the experiment included restlessness, jumping, erratic swimming, air gulping at the surface, loss of balance, lethargy, increased opercular movements, and instances where the fish lay motionless on the water surface before death, along with morphological changes such as skin discoloration, pigmented patches on the body, scale shedding, chemical sedimentation on the body, increased mucous secretion, and ballooning in the exposed fish. The data collected indicate that Catla catla is a suitable bio-indicator for identifying heavy metal contamination in freshwater environments.