**4. Conclusions**

Heavy metal pollution is global treat and increasing day by day, due to many natural and anthropogenic activities, which disturb natural composition of soil, water and air, but also of living organisms [3, 23].

*Toxicity of Heavy Metals DOI: http://dx.doi.org/10.5772/intechopen.102441*

These metals can enter the body from sources of contamination by ingestion, inhalation or dermal contact, where they are absorbed, then bioaccumulated in various organs or target tissues, for different periods of time [5, 22]. The most important is the occupational exposure for those working in industries where these metals are produced or used, which can be reduced by various engineering solutions [1].

Heavy metals can affect organs and their functions, causing adverse effects in humans like, cardiovascular, neurologic, gastrointestinal, immunologic, endocrine, reproductively disorders, but also various types of cancer, including lungs, bladder, skin. But, the severity of those side effects depends on chemical state, time and dose of exposure, solubility [22].

In order to prevent exposure to these metals, as well as the occurrence of health problems, it is important to establish safety limits for different matrices [19].
