Heavy metals in vegetables and their impact on the nutrient quality of vegetables: A review

ABSTRACT

Vegetables are vital to the human diet, and in particular provide the well-known nutrients to maintain normal physiological functions. The prolonged application of large amount of fertilizers and pesticides has resulted in heavy metal accumulation in vegetable gardens. Exposure to heavy metals by the consumption of contaminated vegetables and its toxicity is a serious concern. This article reviews the presence of heavy metals in different vegetables, their mechanism of absorption, impact of heavy metals on physiology, and nutrient reduction and associated impact on humans with emphasis on pregnant women based on the existing scientific literature. However, a limited number of studies was found in the data base that examined the reduction of nutrients in the vegetables due to heavy metal contamination. The heavy metals were found in 36 vegetables in 61 regions of the world and were above permissible limits in most of the vegetables. Specific study to human toxicity due to the contamination of heavy metals may be conducted with emphasis on pregnant women, children, and elderly people. Furthermore, strategy and policy should be devised to control the heavy metals in vegetables and those vegetables that are hyper-accumulators of heavy metals should be identified for awareness purposes.

KEYWORDS:

• contamination
• heavy metals
• nutrients
• physiology
• risk
• vegetables

Acknowledgments

The authors are highly thankful to the Head of the Department of Environmental Science, Jiwaji University, Gwalior for providing technical and moral support for the present study. We are also grateful to the Head of School of Studies in Pharmaceutical Science, Jiwaji University, Gwalior (India) and management ITM University, Gwalior (India) for all the support.