Heavy Metals in Food Crops: Ideal Sources and Roles of Urban Agriculture in Facilitating Their Consumption- A Review

Abstract

The qualities of agricultural soil and water are diminishing continuously due to the rigorous anthropogenic activities currently stocking the soil with a lot of toxic chemicals including heavy metals. Heavy metals are highly persistent and non-biodegradable, control of their contamination is very tricky to handle. Their presence in soil and water is detrimental to food crops and humans. Various sources of heavy metals contaminants and the role of urban food production on human heavy metal contamination were discussed.Heavy metals have their way into the soil and food crops through wastewater irrigation and production in contaminated soil. The habitual heavy metals contamination sources for food crops are wastewater irrigation, abuse of agrochemicals, production in the contaminated field, atmospheric deposit when foods are exposed to contaminated air, and unethical mining activities. Agricultural soil in urban and peri-urban areas are heavily contaminated with heavy metal due to various anthropogenic activities. Wastewater irrigation intensify the contamination by supplying the soil with more heavy metals. The heavy metals are passed to food during production and subsequently to humans after consumption.

Toxic Metals Levels in Agrochemicals Sold in Sabon Gari Market, Kano, Northwestern Nigeria

“…Pb is known to be among the major toxic metals that has been classified due to its toxicity profile (Uzu et al, 2009;Chauhan et al, 2020). Even at low concentration, it could result in devastating effects to plant growth, crop yield, and general productivity (Ashraf et al, 2017;Abdullahi et al, 2021). These is due to the fact that Pb reduce nutrient uptake, induce DNA damage, destroys shoot and root, deactivate the membrane permeability and degenerate the activities of enzymes (Reddy et al, 2005;Gichner et al, 2008;Ashraf et al, 2015).…”

Small‐scale silvopasture: Addressing urban and peri‐urban livestock challenges in the United States with agroforestry practices

“…Both the phytoavailablility and bioaccumulation in food products are dependent on several different factors including soil pH, redox potential, soil clay content and soil cation exchange capacity, organic matter, aging of added elements, nature and quantity of elements, and details of the soil–plant interface such as the impact of the rhizosphere microflora and levels of root exudates (Antoniadis et al., 2017). Several papers and reviews have focused on the issue of bioaccumulation of metals in vegetables and other products (Abdullahi et al., 2021; Romanova & Lovell, 2021). Some show little plant uptake and bioaccumulation in several vegetable and agroforestry tree species.…”