The environment and its compartments have been severely polluted by transition metals. This has compromised the ability of the environment to foster life and render its intrinsic values. Heavy metals are known to be naturally occurring compounds, but anthropogenic activities, especially combustion of fossil fuels, introduce them in large quantities in different environmental compartments (Prüss-Üstün, 2016; Odunlami et al., 2018; Olukanni. and Adeoye, 2012). Transition metals can have deleterious, toxic and carcinogenic to humans when ingestion or inhaled in higher concentrations (Panne et al., 2001). More than 20 different transition metals toxins have negative impacts on human health and each toxin will produce different behavioural, physiological and cognitive changes in exposed individuals (Extreme health USA, 2005). The degree to which a system, an organ, a tissue or a cell is affected by a transition metal toxin depends on the toxin itself and the individuals’ degree of exposure to the toxin (Soleimani et al., 2018). Combustion of fuels contaminated with metals has been found to contribute toxic transition metals to the environment – air, water bodies and soil (Wong, 2013).

The largest sources of airborne cadmium (Cd) in the environment are the burning of fossil fuels such as coal or oil, and incineration of municipal waste materials. Cadmium may also be emitted into the air from zinc, lead, or copper smelters (U.S. Department of Labor, 2004). Cadmium emitted into the environment pollutes water bodies and land and is eventually ingested by plants and animals which are then ingested by human beings (WHO, 2010; Molognoni et al., 2017). Humans are commonly exposed to cadmium by inhalation and ingestion. Cadmium enters in air from both natural and anthropogenic sources and bind to small particles where it can combine with water or soil causing contamination, in nano-form, of fish, plants and animals (Honey et al., 2015). Spills at hazardous waste sites and improper waste disposal can cause cadmium leakages in nearby habitats. Foodstuffs like liver, mushrooms, shellfish, mussel, cocoa powder and dried seaweed are cadmium rich increasing the concentration in human bodies (Honey et al., 2015). While it is necessary in small amounts for biological processes in human beings, larger amounts of the substance are toxic and can have devastating effects ranging from stomach irritation to kidney failure (Akhilesh et al., 2009). The Joint FAO/WHO has recommended the provisional tolerable daily intake (PTDI) as 0.007 mg/kg body weight for cadmium (JEFCA, 2004). The EPA maximum contaminant level for cadmium in drinking water is 0.005 mg/L whereas the WHO adopted the provisional guideline of 0.003 mg/L (WHO, 2004)…(by F.B. Elehinafe, A.O. Mamudu, O.B. Okedere, A. Ibitoye)