Heavy metals in contaminated soil: source, accumulation, health risk and remediation process

Abstract

Heavy metals contamination of soil is an issue of global concern that ultimately results in toxicity and diseases in humans and animals through consumption of food crops from contaminated soil. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. Heavy metals in the soil refers to some significant heavy metals of biological toxicity, including Cobalt (Co), Cadmium (Cd), Lead (Pb), Chromium (Cr), and Arsenic (As) etc. With the development of the global economy, both type and content of heavy metals in the soil caused by indiscriminate use for human purposes has altered their geochemical cycles and biochemical balance. There are many known sources of harmful metals, including the earth, which releases them into food, air, and water, and anthropogenic activities, such as the application of fertilizer in agriculture, the use of pesticides and herbicides, and irrigation. Other sources are automobile emissions, paints, cigarette smoking, industries, and sewage and waste disposal. This review gives details about some heavy metals their toxicity, bioaccumulation, biodegradation, mobility and solubility in contaminated soil along with their health effects. Remediation of heavy metal in contaminated soils is necessary to reduce the associated risks, make the available soil safe for agricultural production, enhance food security and scale down land tenure problems arising from changes in the land use pattern the review recommends regular monitoring of heavy metals in soil, vegetables and foodstuffs to prevent excessive accrual in food chain.