Heavy Metal Contamination: Impacts From Plants to the Food Chain and Eco‐Friendly Amelioration Strategies

ABSTRACT Heavy metal (HM) pollution, resulting from human activities such as mining and the excessive use of agricultural chemicals, poses a serious threat to global agriculture and food security. This review examines recent research (2015–2025) on the adverse morpho‐physiological effects of key HMs—including cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), zinc (Zn), copper (Cu), chromium (Cr), and nickel (Ni)—on various plant species. Exposure to these nonbiodegradable and toxic elements disrupts vital plant processes from germination to maturity, manifesting as inhibited seed germination, altered root architecture, reduced biomass, and significant yield loss. The primary mechanism of HM toxicity is oxidative stress, triggered by reactive oxygen species (ROS) that damage cellular components. Heavy metals also disrupt photosynthesis by degrading chlorophyll and inhibiting photosystem II. Furthermore, they interfere with nutrient uptake, leading to deficiencies and morphological symptoms such as chlorosis and stunted growth. The accumulation of HMs in edible plant tissues introduces these toxins into the food chain, posing serious risks to human health—including neurological, renal, and hepatic damage, as well as carcinogenic effects. To mitigate these impacts, this review highlights promising and sustainable strategies such as the application of biofertilizers, biochar, and nanoparticles. These amendments alleviate HM stress by enhancing antioxidant defenses, reducing metal bioavailability and uptake, improving soil health, and promoting plant growth, thereby offering a viable path toward safer food production and environmental remediation.