Effects on Human health
Heavy metal toxicity can result in damaged or reduced mental and central nervous function, lower energy levels, and damage to blood composition, lungs, kidneys, liver and other vital organs(Zevenhoven and Kilpinen 2001; Nies, 2003).Effects of heavy metals on human health are most extensively studied and regularly reviewed by international bodies such as the WHO. Long-term exposure may result in slowly progressing physical, muscular and neurological degenerative processes that mimic Alzheimer’s disease, Parkinson’s disease, muscular dystrophy and multiple sclerosis.  Health concern related to heavy metals might be mainly divided into two types, i.e. heavy metal poisoning caused by excessive extrinsic exposure and genetic disorders such as Wilson disease. Acute and chronic arsenic toxicity, as well as arsine gas toxicity involves adverse impacts on the nervous, cardiovascular, respiratory, gastrointestinal, hepatic, renal, hematopoietic, immunological and dermatologic systems. It is generally accepted that food crops grown on cadmium containing soils or soils naturally rich in this metal are the major source of exposure to humans (Shukla and Singhal, 1984).Some metals are toxic at low concentrations also e.g. Arsenic, mercury, lead and thallium (Kimberlie et al., 1998; Järup, 2003).