Heavy Metals in Agricultural Soils; Origins, Distribution and Effects

Heavy metals are natural components of the earth’s crust and their concentration and distribution may differ from one region to another. Due to their high solubility, when discharged to the air, soil and water, they can turn into highly toxic pollutants and adversely affect living organisms. While some heavy metals are very important in trace amounts for living organisms regarding their metabolic activities, some of them cause toxic effects even at low concentrations. Although the effects of heavy metals on the environment and living things vary according to their type and concentrations, they pose a great threat for the people’s health and other living organisms, especially when they enter the food chain through agricultural soils and plants. Nowadays, there are some studies on identifying soils exposed to heavy metal pollution and developing appropriate remediation measures. However, the important point is not to clean the polluted areas, but to prevent pollution or reduce the rate of pollution to a minimum level. In addition, the effects of heavy metals on the environment and living organisms should be well understood. Therefore, in addition to their interactions with agricultural soils and irrigation waters, it is necessary to understand the effects of heavy metals on plant and human health properly. In this study, information about the sources of heavy metals, the way they contaminate agricultural lands and irrigation waters, their effects on soil, water and plants are given by using the latest literature.