<div>Background: Benthic macro invertebrates have a sedentary and long life span, sensitive community response to organic loading, thermal impacts, substrate alteration and toxic pollution. They are regarded as the most informative bio indicators of water pollution. Macro invertebrates and water quality are interrelated to each other, as macro invertebrates are a potential indicator of water quality and therefore have been most frequently used in biomonitoring studies. 
 
Methods: The study area is the tailrace of Dikhow River, a 65 km. a southern tributary of the mighty river Brahmaputra. The stretch was demarcated into five sectors longitudinally. The study was done for a period of two years during which sampling collection was done using sampling methods. Appropriate sized net was used to sample macroinvertebrates. Identification was done using standard identification keys. Pollution tolerance of the species was measured using standard protocols. Using tolerance values, family biotic Indices were measured by Hilsenhoff standard protocols. 
 
Result: Number of pollution sensitive macroinvertebrates were found to be minimum in almost all stations indicating the level of pollution in the stations. Macroinvertebrates with higher tolerance levels were recorded in maximum numbercompared with the standard values to assess the water quality. A total of thirteen (13) species (Rhynchobdellasp, Physellasp, Soletelinasp, Gammarussp, Fenneropeneussp, Isotomussp, Caeniussp, Gomphussp, Lethocerussp, Hydrophylussp, Chaobarussp, Chironomussp) have been recorded during the study period. Among them the species with high pollution tolerance values were recorded in higher number during the study. While compared the family biotic indices as recorded from the stations with the standard data, then station I and station III have been found to&nbsp; be significant organic pollution and other three stations were found to be Fairly significant organic pollution.</div>

A Study of River Water Quality using Macroinvertebrates as Bio Indicator: A Case Study

<div>Background: Water quality monitoring is vital for the sustainable conservation of water resources. Benthic macro invertebrates have been documented as the best indicators of water quality serving as a vital link in the aquatic food web. The present work was carried out at Dikhu River, Mokokchung, Nagaland. 
 
Methods: The analysis of water samples was done by adopting standard methods and compared against the W.H.O. 1995 drinking quality standards of water. The macroinvertebrates were collected with the help of the Surber and preserved in 5% formalin and examined using inverted microscope. Pearson&rsquo;s correlation analysis were performed by IBM SPSS package 16.0. 
 
Result: All water parameters were within the permissible limit of drinking quality standards except for alkalinity. A total of 646 individual benthic macro invertebrates belonging to three taxa (Annelida, Arthropoda and Mollusca) were recorded during the study. The study depicts the present status of macrobenthic structure of Dikhu River of Nagaland and aims to lay the foundation for further effective work as future prospect.</div>

A Study of River Water Quality using Macroinvertebrates as Bio Indicator: A Case Study

Effect of Water Quality on Benthic Macro Invertebrates in Dikhu River, Nagaland, India