Heavy Metal Contamination in Agricultural Soil: Environmental Pollutants Affecting Crop Health

Abstract

Heavy metals and metalloids (HMs) are environmental pollutants, most notably cadmium, lead, arsenic, mercury, and chromium. When HMs accumulate to toxic levels in agricultural soils, these non-biodegradable elements adversely affect crop health and productivity. The toxicity of HMs on crops depends upon factors including crop type, growth condition, and developmental stage; nature of toxicity of the specific elements involved; soil physical and chemical properties; occurrence and bioavailability of HM ions in the soil solution; and soil rhizosphere chemistry. HMs can disrupt the normal structure and function of cellular components and impede various metabolic and developmental processes. This review evaluates: (1) HM contamination in arable lands through agricultural practices, particularly due to chemical fertilizers, pesticides, livestock manures and compost, sewage-sludge-based biosolids, and irrigation; (2) factors affecting the bioavailability of HM elements in the soil solution, and their absorption, translocation, and bioaccumulation in crop plants; (3) mechanisms by which HM elements directly interfere with the physiological, biochemical, and molecular processes in plants, with particular emphasis on the generation of oxidative stress, the inhibition of photosynthetic phosphorylation, enzyme/protein inactivation, genetic modifications, and hormonal deregulation, and indirectly through the inhibition of soil microbial growth, proliferation, and diversity; and (4) visual symptoms of highly toxic non-essential HM elements in plants, with an emphasis on crop plants. Finally, suggestions and recommendations are made to minimize crop losses from suspected HM contamination in agricultural soils.

Nanotechnology Approaches for the Remediation of Agricultural Polluted Soils

“…Large volumes of garbage are produced during mining activities and are gathered at waste accumulation sites . These expanding trash heaps have a negative effect on some places and may turn some agricultural regions into wastelands . When exposed to concentrations exceeding the recommended limits, heavy metals cause harmful toxicity to aquatic organisms, plants, and humans.…”

“…Soil pollution by heavy metals poses significant risks to human health and ecology . Heavy metal contamination poses a significant risk to the environment and food security owing to the rapid expansion of the agricultural sector and related industries . In addition, the massive expansion of the global population has led to a disturbance in the natural habitat, which has raised the level of heavy metal contamination on Earth.…”

“…In addition, the massive expansion of the global population has led to a disturbance in the natural habitat, which has raised the level of heavy metal contamination on Earth. One of the more important fields of environmental research is the management and prevention of heavy-metal contamination . Chemical, physical, and biological methods have been used to extract heavy metals from the environment.…”

Influence of soil characteristics on the concentrations of Cr, Pb, and Zn in tobacco leaves from Longyan, China, and the associated predictive models

“…The rigorous assessment and strategic mitigation of heavy metal threats within agroecosystems have perennially occupied a central position in environmental and agricultural research [55,56]. This heightened interest emanates from the intricate interplay of variables within agricultural terrains, encompassing fluctuations in soil heavy metal concentrations, physicochemical properties, climatic variables, topographical nuances, soil taxonomies, and agronomic practices [57,58].…”

Quantitative analysis of potentially toxic elements in soil by XRF based on efficient reinforcement learning and sparse partial least squares

“…However, potentially toxic element contamination of these soils is a growing concern due to its potential hazards to human health and the environment. 1 When the concentrations of potentially toxic elements accumulate to toxic levels in agricultural soils, these non-biodegradable elements adversely affect crop health and productivity and even directly threaten human health when ingested. For non-essential potentially toxic elements like cadmium (Cd), barium (Ba), and lead (Pb), 2 direct ingestion may cause a range of health hazards, including kidney damage, cancer, and neurological disorders.…”