**Abstract**

Fast consumption, increasing energy needs, unplanned urbanization, and unconscious discharge of industrial wastes cause pollution of air, soil, food and water resources. Among these pollutants, heavy metals and metalloids are not biodegradable and accumulate in compartments such as water, soil and plants, threatening human and environmental health. Monitoring studies show that heavy metals such as arsenic, lead, mercury, cadmium, nickel, zinc, copper, chromium and trace elements are in first place according to their availability in the environment. Preventive and remedial measures should be taken to reduce the effects of heavy metals. Legal regulations, monitoring studies, the use of soluble and nontoxic compounds in environmental compartments (air, water, soil and plants) in industrial processes, heavy metal-free pesticides, appropriate wastewater treatment plants and use of renewable energy sources instead of fossil fuels are among the priority measures to reduce concentrations of heavy metals in the environment. As a bioremediation approach, removing toxic wastes from the environment by using bioaccumulatory organisms such as plants or mussels maintains its importance among studies aimed at recovery. Studies have shown that integrated methods especially the combination of suitable plants and microorganisms - are very effective in mitigating the effect of heavy metals in the environment.

**Keywords:** heavy metal, environmental matrix, mitigation, human health, ecosystem health, bioremediation

## **1. Introduction**

While the 21st century offers many technological possibilities to the service of humanity, humans try to dominate nature by using science and technological facilities and change the existing balance. The deteriorating natural balance and environmental problems that occur as a result are the most important hazards that threaten health in our age. The effects of climate change increase in parallel with increasing environmental problems. With industrialization, mining, pesticide use and increasing energy needs, heavy metals come to the forefront primarily in relation to occupational diseases, and they are also among the pollutants that disrupt the ecological balance as a result of water, soil and air pollution. Under normal conditions, the proportion of heavy metals in nature is low. When the concentration ratio in the natural environment increases, heavy metals such as arsenic, mercury, cadmium, chromium and lead have toxic effects, especially on organisms, and inhibit enzymes. They create environmentally toxic effects with their non-degradable and accumulatory properties in environmental compartments [1–3]. While some

metals are important as trace elements for living organisms, they may accumulate in living organisms above a certain concentration and cause toxic effects or they can convert to other compounds in the environment; during this transformation, toxic and water-soluble compounds of a metal may sometimes occur. For this reason, heavy metals and trace elements are classified as vital and non-vital according to their degree of participation in biological processes. Those defined as vital must be present at a certain concentration in the structure of the organism. Because these metals participate in biological reactions, they must be consumed regularly in foods. For example, copper is an indispensable element in red blood cells and in many oxidation and reduction processes in animals and humans. On the other hand, nonvital heavy metals can cause health problems by affecting the physiological structure even at very small concentrations. The best example of this group is mercury, which binds to sulfurous enzymes. Whether a heavy metal is necessary for living organisms depends on the organism being considered. For example, while nickel is toxic to plants, it must be present as a trace element in animals [4–6].
