investigation of heavy metals (cadmium, lead) in chironomidae and gammarus pulex namrood river – tehran province

marine ecosystem pollution is one of the important problems of today environment. in this study the existence of heavy metal in the namrood river, situated in firoozkooh in tehran province, iran has been investigated. the namrood river is located near firoozkooh route, and is affected by pollutant from tourist centers, entertainment, gas stations, nearby villages’ sewage systems, farming effluent, and hatchery farms. in some areas, its water is heavily polluted possibly by heavy metals. after selecting two stations in upstream and downstream of the river, they were sampled three times in both cold and hot seasons of year (mid-march, and june) for chironomidae, and gammarus plux sediments. the measured heavy metals were cadmium and lead. the results showed that the concentration of cadmium in measured samples varied from 0.010-0.2033 ppm. the concentration of lead in samples varied from 0.11-2.16 ppm. the results also indicated that sediments of samples taken from the upper station in the cold season had a higher proportion of cadmium and a higher concentration of lead  than  sediments in the lower station during the hot season.