heavy metals phytoremediation by aquatic plants (hyrocotyle ranocloides, ceratophyllum demersum) of anzali lagoon

wetlands are often considered sinks for contaminants, and aquatic plants have been shown to play important roles in wetland biogeochemistry through their active and passive circulation of elements. in this research, in order to evaluate the concentration level of heavy metals released by the urban, industrial and agricultural activities at the margin of the rivers flowing into anzali lagoon, as well as finding lead and cadmium accumulated in two plant species quoted below, a sampling has been made on two kinds of aquatic plants in the lagoon at three randomized stations based on the density of the plant coverage. in this project two regional aquatic plant species ashyrocotyleranocloides, ceratophyllumdemersumhave been investigated for absorption of lead and cadmium. results show an average concentration of lead in ceratophyllum being 53.11 ppm, for hydrocotyle 77.8 ppm, and of cadmium in ceratophyllum being 4.46 ppm and for hydrocotyle 6.28 ppm. according to results, lead has been the most abundant between these two metals inside plant organs regardless the specie. the statistic test gives the results under the confidence level 95% proving the amount of the absorption being significant in the stem of hydrocotyle plant rather than in the root or the leaf compared with other species.