Histopathological and Haematological Changes Induced on Exposure to Bisphenol A in Etroplus Suratensis

Abstract- Pollution in the aquatic environment has become a major threat in freshwater and marine water systems. Additives such as Bisphenol A (BPA) is an industrial chemical used to manufacture plastics to improve performance. They are not covalently bound to plastics and thus leaching from a product into the environment occurs. BPA is a structural analogue of estrogen that binds to the estrogen receptors. It is a known endocrine-disrupting chemical (EDC) ubiquitous in the aquatic environment and is an Eco toxicological risk for the health of aquatic organisms. As they behave like estrogen mimics, they interfere with the body’s ability to regulate growth, development, metabolism, particularly reproduction. Although BPA has been banned in many countries including the US, Europe and China because of its harmful effects, it has not yet been banned in India. BPA that leached from the discarded plastics directly affect the natural population of fishes in our coastal waters as India has a vast costal line and the experimental organism that was used are Etroplus suratensis, endemic to the southern coast. The experiment comprised of 6 groups of fishes each carrying 6 fishes including control. The fishes are then exposed to Bisphenol A at concentrations of 2 ppm, 4 ppm, 6 ppm, 8 ppm and 10 ppm respectively for 96 hrs and the lethal concentration value was found to be 6 ppm. The exposed fishes showed erratic movement, excess secretion of mucous, changes in opercular movement. Also, the fishes coming up to the surface of the water and then lying near the corner of the tank were observed. In all treatment tanks after exposure to sub lethal concentrations of chemical for 2 weeks, the blood was collected for haematological studies. The haemoglobin content showed a decrease in concentration when compared to the control fish. As the concentration of the chemical increased there was a decrease in the Hb content. Upon post-mortem examination, the exposed fishes did not show any difference in the external appearance or in the internal organs from the control group. After histological analysis, it is found that the hyperplasia of the secondary lamellae, lifting of the epithelial membrane in gills, changes in gonads such as deformation of matured ooplasm, vacuolation of mature oocyte and thickening of the vitelline membrane occurred. Vacuolation of hepatocytes, melanomacrophages in liver tissues and an increase in the number of melanomacrophages cells and white pulp area in spleen occurred. The pathology in each concentration was similar but the extent of changes increased with exposure concentration.