quality of lighvan chai river based on biological factors

this study was organized to investigate the effects of domestic and industrial effluents on lighvan chai water quality using macroinvertebrates community and the concentration of nitrat and phosphate. based on persampling results, seven sampling site were selected. aamples were collected in april, may and june 2010. seventeen families of macrobentics were found in lighvan chai river and siimolidae and chirnomidae were dominant in all sites. the concentrations of nitrate and phosphate showed some fluctuation from april to june, however in site 1their concentrations were stable from 0.0 to 0.1 ppm, respectively. in site 7, nitrate and phosphate concentrations changed from 6.7 and 5.8 in april to 8.2 and 7.3 in june, respectively. the population of beatidae, leptoceridae, chironomidae and siimoliidae families showed significant (p