Investigating the Impact of Industrial Wastewater from Khuzestan Steel Industries on Heavy Metal Accumulation and Morphological Characteristics of the Medicinal Plant Dracocephalum moldavica L.

Introduction: This study examines the effects of different concentrations of industrial wastewater on the growth, yield, and heavy metal accumulation (lead, nickel, and cadmium) in Dracocephalum moldavica L. (badrashb). It aims to evaluate how wastewater irrigation affects the plant's morphological traits and the potential environmental risks of toxic metal uptake. The findings provide insights into the safe use of industrial effluent for growing medicinal plants in arid regions. Methods: A greenhouse experiment was conducted using a completely randomized design with five treatments (0%, 25%, 50%, 75%, and 100% wastewater) and three replications. At the end of the cultivation period, heavy metal accumulation was determined after sample digestion using an AA-67OG Shimadzu apparatus. Morphological characteristics were analyzed using SPSS software version 22. Results: The results indicated that the highest increase in morphological parameters was observed in the 75% wastewater treatment. Accumulation of lead and cadmium in the roots and aerial parts showed significant differences between the various treatments (P<0.05). The highest concentrations of lead and cadmium in the shoots were 4.16 and 1.6 mg/kg, respectively, in the 100% wastewater treatment, while the lowest concentrations were found in the control treatment. Additionally, the transfer factor of cadmium from the roots to the shoots was higher than that of lead. Conclusion: Irrigation with industrial effluent resulted in the accumulation of lead and cadmium in Dracocephalum moldavica, with cadmium levels surpassing the WHO standard for medicinal plants. This highlights the environmental risks associated with wastewater irrigation. If wastewater is to be used, it must be properly treated to meet irrigation standards in order to reduce potential health hazards.