Quality of Lighvan Chai River Based on Biological Factors

Document Type : Research Paper


1 Tabriz Branch, Islamic Azad University, Department of Environment, Tabriz, Iran

2 Assistant of Professor, Department of Environment, Faculty of Natural Resources, University of Tehran, Karaj, Iran


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<0.05) changes from dite 1 to site 7, during sampling period. Family biological index (Hilsenholf Indicator) changed from 3.30 in site 1 to 7.61 in site7 in June. The index showed the water quality of site 1 belongs to pure class (II) and water quality decrease toward downstream, so that the water quality of site 7 belong to polluted class (VI). Although water of sites 1, 2 and 3 were showed to be non-polluted, intensive development of tourism, ranching and dairy industry and the entrance of domestic, agricultural and industrial wastewater might result in pollution of water body.