Purification of some industrial waste water contaminants entering the Caspian Sea basin using vetiver plant

Today, with the increase in world population and the subsequent development of industries and factories, the amount of effluents entering the environment, which often contain heavy metals and various other pollutants, is increasing. Heavy metals have devastating effects on plant and animal health in various ecosystems. In the process of environmental purification, plants are able to absorb heavy metals and can absorb these pollutants from soil and water and store them in their roots and shoots.

In this regard, in order to investigate the uptake and accumulation of heavy metals by plants, an experiment was conducted in a completely randomized design with three replications using vetiver plant. Plants treated with industrial effluent and control plants were irrigated with municipal water. Also, pots containing soil without plants were considered to measure the amount of elements in the soil during the six-month experiment period, they were regularly irrigated with other pots with industrial effluent. In order to investigate the effect of irrigation with effluent on the yield of vetiver plant, after a six-month period of experiment, heavy element analysis and anatomical and physiological studies were performed on plants treated with industrial effluent and control plants. Transfer and accumulation factors, which are two important factors in measuring plant ability for phytoremediation, were also examined.

The results of this study showed that among the most heavy metals in industrial effluents, which included zinc and chromium, most of the mentioned elements were stored in the roots of vetiver and less were collected in the aerial parts. Also, the results of physiological traits experiments showed that the factors of soluble sugars and proline in the treated plants increased compared to the control and the concentration of malondialdehyde in the treated plants decreased compared to the control. The results of root studies in control and treated plants showed that root diameter, central cylinder diameter and number of vascular clusters in treated plants increased compared to control.

Overall, the results of this study showed that in the process of absorption of heavy metals, changes were made in some anatomical and physiological traits of treated plants. Examination of transfer and bioaccumulation factors also showed that vetiver has the ability to absorb zinc and chromium through plant stabilization.