Heavy metals contamination in vegetable crops irrigated with wastewater: A review

Abstract

The demand for quality fresh water for agriculture has made waste water application popular for use and heavy metals contamination issues becoming increasingly globally with many documented cases of metal toxicity in mining industries, foundries, smelters, transportation, coal-burning power plants and agriculture. This paper attempted to collate and compile the research literature pertaining to the heavy metal contamination in vegetables irrigation with wastewater. It also reviews deeply about effect, uptake and accumulation of heavy metal in vegetables. Uptake and translocation factor of heavy metal from soil to edible parts of vegetables were quite distinguished for almost all elements examined. However, because of heavy metals bioaccumulation, non-degradability, and its presence in wastewater, contaminates vegetables and cause toxicity to human beings and the functioning of the entire ecology. This is a major issue of concern within the study of environmental science and geochemistry. Although, the issue is a menace, as such requires immediate attention for the developing countries, where the pressure of the teaming population escalates the exigency for human sustainability, food security, and total eradication of hunger. Globally, studies have examined some of these important issues, but most of these studies are fragmented and limited within the purview of mostly individual states and localities within the countries. On a wider geographical scale, the discussion and perspectives of vegetables irrigated with contaminated wastewater offer insufficient insight and expose merely a snapshot of the actual situation in which developing countries are lacking. Thus, the present study synthesizes existing literature and their findings to create a knowledge base on the vulnerability of the vegetables in developing countries. Thus, it is evident from the several research findings that heavy metals contaminate vegetables and has toxic effects humans and animals after certain limits.