• A K Tyagi

      Articles written in Proceedings – Animal Sciences

    • Pollutional studies of few rivers of Western Uttar Pradesh with reference to biological indices

      S R Verma A K Tyagi R C Dalela

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      The pollution studies of four rivers of Western Uttar Pradesh with reference to biological indices are reported. Physico-chemical and biological characteristics of the river water at 16 sampling points have been studied and the correlation between them have been made. It is observed that the species number (n) and the total number of organisms (N) of the phytoplankton and zooplankton, though exhibit a relationship at certain stretch with the increase or decrease of pollution intensity yet it is not found very specific and so no definite conclusions could be made. However, the quantitative and qualitative changes in the distribution of benthic macroinvertebrates are clear and specific. Benthic production is observed lower at the points having BOD below 20 mg/l, perhaps because of low availability of food, while at 110 mg/l BOD the highest benthic production (547 per Ekman grab) was observed and this may be due to the presence of good amount of food. Further, the species number (n) and organism number (N) of benthic fauna decline very much and finally disappear completely with the increase of BOD i.e. more than 310 mg/l or with the disappearance of DO (dissolved oxygen).

    • Acute toxicity of five synthetic detergents toChanna punctatus andSaccobranchus fossilis

      S R Verma N Pal A K Gupta S K Bansal A K Tyagi M C Bhatnagar R C Dalela

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      The acute toxicity of five synthetic detergents to two freshwater teleostsChanna punctatus andSaccobranchus fossilis has been worked out. The LC50 values and slope function (S) for one nonionic and four anionic detergents were determined at 24, 48, 72 and 96 hr intervals by graphical interpolation and probit analysis. Side by side regression equations for all exposure time intervals and fiducial limits for LC50 at the 96 hr exposure were calculated. The relative potency of synthetic detergents was in the decreasing order from nonionic to anionic for both the fishes respectively. The relative susceptibility was highest for nonionic than anionic respectively forChanna punctatus in comparison toSaccobranchus fossilis.


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