Title : Heavy metal phytoremediation potential of Helianthus annuus (Mammoth sunflower) in a hydroponic system Notes:
Abstract:
Heavy metal contamination poses a significant threat to agricultural productivity, ecosystem stability, and human health due to the persistence and bioaccumulative nature of contaminants such as lead (Pb) and arsenic (As). Conventional remediation strategies are often expensive, labor-intensive, and environmentally disruptive, creating a need for sustainable alternatives. Phytoremediation, the use of plants to remove, stabilize, or accumulate environmental contaminants, has emerged as a promising green technology for addressing heavy metal pollution. This study evaluates the phytoremediation potential of Helianthus annuus L. (Mammoth sunflower) grown in a deep-water culture hydroponic system under controlled exposure to lead and arsenic. A hydroponic approach was selected to eliminate soil variability and precisely control nutrient availability, pH, and contaminant exposure. Sunflower plants were exposed to lead nitrate at concentrations of 5, 10, and 20 mg/L and sodium arsenate at concentrations of 1, 5, and 10 mg/L, alongside untreated controls over a 28-day exposure period. Throughout the experiment, plant morphological and physiological responses were monitored, including plant height, root length, leaf number, chlorophyll content, and visual stress symptoms such as chlorosis and necrosis. Preliminary results indicate that arsenic exposure produced a concentration-dependent reduction in plant growth, leaf production, root development, and chlorophyll content, suggesting a stronger phytotoxic effect than lead. Lead treatments elicited more variable responses, with lower concentrations maintaining growth patterns closer to control plants. Plant tissues (roots, stems, and leaves) were harvested for heavy metal quantification using Inductively Coupled Plasma–Mass Spectrometry (ICP-MS). Metal accumulation, translocation, and remediation efficiency will be evaluated through bioconcentration and translocation factors to determine the plant's capacity for contaminant uptake and redistribution. Subsequently, this research provides grounding data for developing sustainable phytoremediation strategies applicable to contaminated environments contributing to scalable, plant-based remediation approaches that support environmental restoration and community health.
