Effect of Industrial Pollution on Fish in the Narayani River, Central Nepal

  • S. K. Sah Department of Zoology, Patan Multiple Campus, Patan Dhoka, Lalitpur
  • P. Acharya Wetlands Nepal, GPO Box 8975, EPC 1444, Kathmandu
  • V. A. Lance Center for Reproduction of Endanged Species, Sun Diego Zoological Society, Sun Diego, California


Industrial effluents, when discharged into rivers, may cause deleterious effects on fish and other aquatic oganisms. In Nepal, the Narayani River has been receiving effluents from several industries including the Bhrikuti Pulp and Paper Mills. Thus, the main objective of this study was to determine impact of industrial pollution on fish fauna and to estimate the level of the heavy metal content in the tissues in fish from the above river Fish samples were collected from three sites, viz. Site-1 near Devghat, Site-2 at Gaindakot in the mixing zone, and Site-3 nearTriveni, in two seasons, rainy and summer. Fish were separated by species and analyzed for heavy metal content using atomic absorption spectrophotometry. The results of fish collections from three sites showed that the number of fish species was less in the polluted area i.e. at Site-2, located near the factory outlet. Chemical analysis of the tissues of fish showed that heavy metals were present in the order of Zn>Cu>Cr>Pb>Hg>Cd. The results showed that neither the seasonal nor the site variation was significant with respect to the content of heavy metals in the tissues of the fish collected from the Narayani river However, their effect on other aquatic organisms should also be studied. Similarly, the Narayani River harbors a sizeable population of crocodiles, thus a detail study on the impact of pollution on them is necessary to be conducted.