Medicinal Plant Growth in Heavy Metals Contaminated Soils: Responses to Metal Stress and Induced Risks to Human Health

Abstract

Accelerating heavy metal pollution is a hot issue due to a continuous growth in consumerism and increased activities in various global industries. Soil contamination with heavy metals has resulted in their incorporation into the human food web via plant components. Accumulation and amplification of heavy metals in human tissues through the consumption of medicinal plants can have hazardous health outcomes. Therefore, in this critical review we aim to bring together published information on this subject, with a special highlight on the knowledge gaps related to heavy metal stress in medicinal plants, their responses, and human health related risks. In this respect, this review outlines the key contamination sources of heavy metals in plants, as well as the absorption, mobilization and translocation of metal ions in plant compartments, while considering their respective mechanisms of detoxification. In addition, this literature review attempts to highlight how stress and defensive strategies operate in plants, pointing out the main stressors, either biotic or abiotic (e.g., heavy metals), and the role of reactive oxygen species (ROS) in stress answers. Finally, in our research, we further aim to capture the risks caused by heavy metals in medicinal plants to human health through the assessment of both a hazard quotient (HQ) and hazard index (HI).

Phytotoxicity of metal–organic framework MOF-74(Co) nanoparticles to pea seedlings

“…Second, the released metal ions from MOF materials were easily migrated into stems and leaves, and accumulated in seedlings to directly cause toxicity. 47…”

“…Second, the released metal ions from MOF materials were easily migrated into stems and leaves, and accumulated in seedlings to directly cause toxicity. 47 The toxicity of metal ions depends on the metal species. Co is an essential microelement, but the overdosage of Co leads to phytotoxicity.…”

Current Trends for Lavender (Lavandula angustifolia Mill.) Crops and Products with Emphasis on Essential Oil Quality

“…As for their accumulation, this can vary by species. While some lavenders contained higher levels of heavy metals accumulated in their leaves, L. angustifolia accumulated them in roots and stems [ 124 ]. Lavender could be employed for the use of contaminated soil of otherwise unproductive, polluted land.…”

Heavy Metal Contaminants in Popularly-consumed Vegetables of Freetown, Sierra Leone

“…Human health may also be endangered by the intake of heavy metalcontaminated plants. Because of their extended biological half-life, non-biodegradability, and ability to accumulate in various body areas, heavy metals are harmful [8]. The use of metal-based herbicides and fertilizers, irrigation with contaminated water, industrial pollutants, and the harvesting process are all elements that contribute to heavy metal pollution [9].…”