The abundance of heavy metals in the environment can be attributed to their natural occurrence as well as their numerous uses in agriculture, domestic and industrial sectors. Industrial untreated wastewater and other untreated water sources often contain high concentrations of heavy metals. When these untreated water and wastewaters are utilized for irrigation, heavy metals may build up in agricultural soil and poison crop plants. Heavy metal pollution of soils presents major risks to the ecosystem and can be harmful to consumers through skin contact and ingestion. The level, mode of exposure, chemical species, and age, gender, and nutritional status of the individual are among the many factors that influence the toxicity of heavy metals, because of their high level of toxicity, As, Cd, Cr, Pb, and Hg are regarded as priority metals with relevance to public health. Since certain metallic elements are known to harm organs even at lower exposure levels, they are classified as systemic intoxicants. The current book chapter discusses heavy metal pollution sources, the toxicological effects of heavy metals on human health, and the assessment of health risks to humans.