pollution of a river by nitrogen and phosphorus

the problem of environmental pollution is of everybody's concern. pollution of zarjoub river in northern iran is most often cause by the uncontrolled disposal of sewage and other wastes resulting from domestic uses of water, industrial wastes containing a variety of pollutants, agricultural affluent from animal husbandry, drainage of irrigation water and urban run-off. a study was carried out to determine the concentration of industrial wastes irrigation water nitrogen and phosphorous in six station of zarjoub river. the analysis was performed according to american standard method. the results of three months water analysis showed that the concentration of nitrogen and phosphorous which annually discharged into the pahlavi lagoon were 931 and 184 tons respectively. for a better analysis a programmed monitoring is required in different seasons.