Investigating the Potential of Native Plants in Phytoremediation of Heavy Metals and Nutrients in the Latian and Lar Dam Reservoirs

Investigation and control of bioaccumulation of heavy metals is very important due to pollution load, ecological risk and very high consequences to human health as well as the uncertainty of the type, amount and manner of pollutants entering water sources. In this regard, determining the level of pollution of heavy metals, nitrate and phosphate in the Latian and Lar dam reservoirs, as well as the potential of Lemna minor, Typha Latifolica and Nasturtium microphyll in phytoremediation of heavy metals and nutrients of these sources were considered in this study. For this purpose, 40 water samples were collected from different depths of Latian and Lar dam lakes as well as 3 samples from the leaves of plant species at random intervals in summer and autumn. After preparing and processing the samples in the laboratory, the average residual concentration of elements was read by ICP. Results showed the mean concentrations of copper, lead, iron and nitrate in Latian dam lake as 0.009, 0.27, 0.10 and 0.07 mg/l, respectively. In Lar dam lake the concentrations were respectively 0.004, 0.26, 0.06 and 1.27 mg/l. In all cases except lead, the values were less than the standard allowable limits. Also, the average phosphate concentrations in Latian and Lar dam reservoirs were 0.07 and 1.27 mg/l, respectively, which was over the standard allowable limit in Lar dam reservoir. Also, in Latian dam, Lemna minor plant has high efficiency in removing lead and phosphate elements, Typha Latifolica has high efficiency in removing iron, and leek juice has high efficiency in removing copper and nitrate. In Lar dam, Typha Latifolica was more efficient in removing iron, copper, lead and nitrate, and leek juice in removing Phosphate. The low average concentration of heavy elements in the reservoir of Lar Dam compared to Latian Dam is related to the considerable area of ​​good pastures and heavy rainfall in the Lar catchment; i.e. the type of land use, vegetation pattern and air humidity in Jajroud and Lar Dam catchments affect this issue.