Evaluation of Weed Plant Species Potential for Phytoremediation in Heavy Metal Contaminated Soil

Abstract

Soil contamination by heavy metals has emerged as a pressing concern in environmental research. The increasing levels of industrialization, emissions from vehicles, excessive use of agrochemicals, and mismanagement of wastes are key contributors to this problem. Heavy metals in soil not only degrade soil fertility but also leach into groundwater, reducing the productivity of arable land and threatening food security. Their entry into the food web further amplifies health hazards for humans and animals. In this context, phytoremediation offers a sustainable and cost-effective solution, as it employs plants to extract, accumulate, and neutralize toxic metals from polluted soils, thereby helping to mitigate environmental risks. With rising concerns over lead, nickel, cadmium, and arsenic contamination in agricultural and urban areas, evaluating weed species for phytoremediation holds promise for ecological restoration and public health. Invasive species like Parthenium hysterophorus and Alternanthera philoxeroides and non-invasive species such as Bidens pilosa have shown potential as hyperaccumulators, leveraging unique root structures, physiological adaptations, and soil microorganism interactions to enhance metal uptake. Parthenium hysterophorus demonstrated up to 2.8-fold higher cadmium accumulation compared to control species, while Alternanthera philoxeroides removed nearly 65% of Pb from contaminated soils within 60 days. Despite its advantages of cost-effectiveness and sustainability, phytoremediation faces challenges, including concerns over ecological impacts, metal toxicity, and its inherently slow process. Addressing these limitations requires optimizing species selection, improving growth conditions, and understanding environmental factors influencing remediation outcomes. Advancing research in this field is essential to maximize the potential of weed-based phytoremediation as a viable solution for mitigating heavy metal pollution.