**7. Chronic health risks linked with the exposure of people to heavy metals through the oral route**

Chronic health effects like diabetes, neurodegenerative diseases, renal damage, bone disorders and tumors of the breast, prostate and lungs have been elicited by Cd in people [64–66].

There are existing reports that indicate that the long-term effects of lead exposure through food and other routes are manifested as anemia, abdominal colic, miscarriages, male infertility, birth defects, renal diseases and behavioral dysfunctions in children [67, 68]. It has also been observed that lead may elicit decreased circulating maternal thyroid hormone thereby influencing growth patterns adversely [67, 68].

It is known that tremendous amounts of arsenic in the soil, food crops (including legumes, cereals, vegetables, etc) and groundwater can stimulate cancer and dermal aberrations, as well as disorders in the heart, stomach, intestines, liver, kidneys and brain, among others [62, 69–73].

Furthermore, excessive copper consumption can activate hepatic damage and other gastric-related problems in people [62, 74, 75]. Wilson's disease, a form of chronic Cu toxicity in human beings, is characterized by alterations in mental states, motor disorders, dysphagia, incoordination, haemolytic anemia, renal and hepatic dysfunctions [72]. It has been shown that human beings become susceptible to chronic copper poisoning when they ingest food items (for instance, legumes, pulses, cereals, etc.) contaminated with copper probably through polluted irrigation sources [76]. Additionally, persistent bronchitis, emphysema, pulmonary disorders and fibrosis were reported in people following long-term exposure to nickel through dietary sources [77].

#### **8. Conclusion**

This review chapter highlighted the mechanisms through which the widespread pollutants, pesticides and HMs, evoke acute and chronic health disorders in human beings. Pesticides are usually applied in agricultural settings for the control of vectors and the enhancement of crop yield, while most HMs are utilized for industrial purposes.

Human beings may be susceptible to various health risks engendered by pesticides and HMs through the consumption of food crops, for example, legumes, contaminated with them. This may eventually pose serious threats to the wellbeing and survival of the populace except if regular monitoring of food items for the residues of these ubiquitous contaminants are conducted globally by the appropriate agencies.

It is envisioned that the information contained in this review chapter will provide a springboard for scientists, researchers and agriculturists, among others, to create innovative techniques for the minimization of human exposures to the residues of pesticides and HMs in order to forestall their pernicious effects in the general population.
