Introduction
Heavy metal pollution is one of the most important environmental hazards found in all human societies. One of the most important of these pollutions is pollution by cadmium, which because of to its effects on the environment, it is necessary to purify it from soil and water. Among these risks, we can mention the increase in the concentration of heavy metals in the environment, the contamination of the human food chain, and the increase in cancer cases. There are various methods for purifying polluted water, among them using the ability of plants, i.e. phytoremediation is a suitable solution for purifying heavy metals from the environment due to its greater compatibility with the environment. Pollution by heavy metals such as lead, nickel, and especially cadmium has been reported in the industrial areas and towns of Golestan province, and even the use of these wastewaters is widespread without performing pollution reduction processes.
Method
in this research, in order to evaluate, prevent and correct the damages of using cadmium-contaminated water, an experiment with 6 treatments and 3 repetitions was conducted in the form of a randomized block design with and without phytoremediation process with the aim of providing irrigation water to rapeseed plants. Reed and vetiver plants were used for herbal treatment. The drip irrigation system was selected. A retention time of 10 days was chosen for the treatment of water contaminated with cadmium, and the irrigation cycle was considered accordingly. During the experiment and after harvesting the rapeseed crop, the amount of changes in the concentration of cadmium in water samples, plant components and soil were measured and analyzed using SAS software.
Result
The results showed that the amount of cadmium accumulated in the seeds of the rapeseed plant and in its aerial parts, in the treatments irrigated with contaminated water after the phytoremediation process by reed and vetiver grass, had a significant decrease of 1% compared to the treatments without phytoremediation. At the end of the growing season, the concentration of cadmium in the soil that was irrigated with water treated with reed and vetivergrass was 1% lower than the concentration of cadmium in the soil irrigated without treatment. Of course, the investigation of the mutual effects of plant treatment on the yield parameters characteristics of rapeseed including height, pod number, stalk diameter, root depth and weight of 1000 seeds indicated that water pollution with cadmium had no significant effect on the mentioned yield parameters.