Human health risks from heavy metals via consumption of contaminated food
Mining and processing metal ore can be a significant source of heavy metal contamination of the environment. The environmental concern in mining areas is primarily related to physical disturbance of the surrounding landscape, spilled mine tailings, emitted dust and acid mine drainage transported into rivers. Excessive accumulation of heavy metals in agricultural soils around mining areas, resulting in elevated heavy metal uptake by plant food, is of great concern because of potential health risk to the local population. The consumption of plants produced in contaminated areas, as well as ingestion or inhalation of contaminated particles is two principal factors contributing to human exposure to metals. Cultivation of crops for human or livestock consumption on contaminated soil can potentially lead to the uptake and accumulation of trace metals in the edible plant parts with a resulting risk to human health. Increasing evidence shows that heavy metal pollution of mined areas caused health damage to the local inhabitants. Serious systemic health problems can develop as a result of excessive dietary accumulation of heavy metals such as Cd, and Pb in the human body. Although Zn and Cu are essential elements, their excessive concentration in food and feed plants are of great concern because of their toxicity to humans and animals. Lead and Cd are considered potential carcinogens and are associated with etiology of a number of diseases, especially cardiovascular, kidney, nervous system, blood as well as bone diseases. Dietary intake is the main route of exposure for most people, although inhalation can play an important role in very contaminated sites. Thus information about heavy metal concentrations in food products and their dietary intake is very important for assessing their risk to human health.