Toxic effects of chlorpyrifos on the growth, hemocytes counts, and vital organ’s histopathology of freshwater mussel, Lamellidens marginalis

The Chlorpyrifos 20 EC (emulsifying concentration) is one of the extensively used agro-pesticide in Bangladesh, most of which are residual in nearby natural water reservoirs. The freshwater mussel, Lamellidens marginalis have been exposed to Chlorpyrifos 20 EC at varying concentrations of Tc 0 mgL-1, T1 2.53 mgL-1, T2 5.07 mgL-1 and T3 10.15 mgL-1 for 35 days to investigate its toxic effects on growth biometrics, hemocyte counts and histopathology of gill, muscle, and ovary. The 96-hour Chlorpyrifos 20 EC LC50 for L. marginalis has been computed as 25.37 mgL-1 from PROBIT analysis. Major water regulating parameters were recorded and analyzed for each treatment group. The specific growth rate (%) was reported statistically highest in TC (0.104 ± 0.412) and lowest in T3 (-0.52 ± 0.38). Similarly, the condition index (CI) and Fulton’s condition factor were decent at TC and downed at T3 (P < 0.05). A high mortality rate occurred in T3 and the lowest mortality in TC. The value of total hemocytes count were also reported to be highest for TC and gradually decreased as the dosage increased (P < 0.05). The histopathology of gill, muscle, and ovary also revealed moderate to severe pathological signs in treatment groups in comparison to control. Administration of Chlorpyrifos 20 EC results in detrimental growth, cytological and hematological alternation in L. marginalis.