Investigation of Qualitative Condition of Nekarud River and Tajan River by NSFWQI Index

Rivers are exposed to large amounts of impurities. The first step for keeping river water quality and purification of polluted parts is obtaining information on the qualitative changes of river water in dimensions of time and place and also, determination of major sources and various water pollutants. Analysis of measured parameters alone or in combination, give in complete information on water quality because of variety of parameters, samples and stations. WQI is a mathematical and statistical tool for conversion of quantitative values of large quantity of water quality data into single number which presents a simple and understandable tool for qualitative assessment. Samples were collected seasonally from stations at upstream, middle stream and downstream of two rivers in east of Mazandaran province (Nekarud River, Tajan River) in a 2 years interval of 2011-2012 years, and analyzed in laboratory of Environmental Protection agency of Mazandaran according to standard methods. The values of NSFWQI (water quality index ofAmerica’s national health organization) were calculated for all stations and all of the stations were located on the level of unsuitable conditions. The condition of Tajan River was relatively better than Nekarud River due to lower residential villages and towns around the river