author(s)
Madhu Sharma, Pooja Chadha and Manoj Kumar Borah

abstract
The present study was designed to evaluate histopathological effects of 4-nonylphenol (NP), in fish, Channa punctatus. ½ of LC₅₀ value was selected as a sublethal concentration for acute exposure (96 hours), while for sub chronic exposure safe application rate was calculated and 1/10^th of it was used for the sub chronic exposure (30, 60 and 90 days). Liver, gill and kidney tissues were analyzed for estimating histological studies. Different histopathological changes after acute exposure like necrosis, vacuolar degeneration, fatty changes and congestion were observed in the liver, while hyperplasia, congestion, degeneration was found in the gill. In the kidney focal area of necrosis, vacuolar degeneration and congestion were seen mainly. On the other hand, during sub chronic exposure gill showed fused secondary lamellae, atrophy in gill filament and telangectasia, while fatty cyst formation and 99% of vacuolar degeneration were seen in hepatocytes. Kidney after sub chronic exposure resulted in pyknosis, atrophy, hypertrophy, hyperplasia, hyperchromic haemopoietic cells, fibrosis and glomular nephritis.