The destructive effects of heavy metals on plant health, soil quality, and agricultural productivity

Heavy metal contamination poses a significant threat to plant health, soil quality, and agricultural productivity. This review explores the sources, physiological impacts, and biochemical mechanisms underlying heavy metals toxicity in plants. Common heavy metals of concern include cadmium (Cd), lead (Pb), mercury (Hg), nickel (Ni), chromium (Cr), copper (Cu), and zinc (Zn), which originate from both natural processes and anthropogenic activities and anthropogenic activities including industrial emissions, fertilizers, pesticides, and wastewater irrigation. Excessive accumulation of these elements disrupts plant metabolism by generating reactive oxygen species (ROS), leading to oxidative stress, enzyme inhibition, membrane damage, and impaired photosynthesis. Experimental studies show that cadmium and nickel stress significantly alter antioxidant enzyme activities—such as catalase, peroxidase, and superoxide dismutase—indicating a defensive response to oxidative imbalance. Morphological symptoms of metal toxicity include chlorosis, stunted growth, reduced yield, and reproductive failure. In addition to direct plant effects, heavy metals disturb soil microbial communities, alter pH, and inhibit processes like nitrogen fixation and decomposition. Effective mitigation requires regular soil monitoring, use of biochar and organic amendments, phytoremediation with hyperaccumulator plants, and balanced nutrient management. Understanding these interactions provides a foundation for sustainable soil management and the development of resilient crop systems in metal-polluted environments. This review synthesizes current understanding of heavy metal ecotoxicology in agricultural systems and emphasizes the need for integrated management approaches to ensure food safety and environmental sustainability.

کلیدواژه ها:

heavy metals ، oxidative stress ، Antioxidant enzymes ، Phytotoxicity ، Soil contamination ، Phytoremediation