Where is iodine found in the world?


Iodine is a chemical element that is essential for the human body, primarily for the production of thyroid hormones. It is also used in various industrial applications, such as pharmaceuticals, photography, and agriculture. In this article, we will explore the different sources and locations of iodine around the world.

1. Natural Occurrence

Iodine can be found naturally in various forms, including iodide, iodate, and organic iodine compounds. It is primarily found in seawater, rocks, and soil. However, the concentration of iodine in these sources can vary significantly depending on the geographical location.

1.1 Seawater

Seawater is the largest reservoir of iodine on Earth. The average concentration of iodine in seawater is about 0.06 parts per million (ppm). However, certain regions have higher iodine concentrations due to geological factors or proximity to iodine-rich areas.

For example, the waters surrounding Japan, Chile, and northern Europe are known to have relatively higher iodine concentrations. These regions are often associated with volcanic activity and have a higher influx of iodine from the Earth’s crust.

1.2 Rocks and Soil

Iodine is also present in rocks and soil, although its concentration is generally lower compared to seawater. The iodine content in rocks and soil depends on factors such as the composition of the parent material, weathering processes, and the presence of iodine-rich minerals.

Coastal areas and regions with volcanic activity are more likely to have higher levels of iodine in their rocks and soil. Inland areas, particularly those far from the coast or volcanic regions, tend to have lower iodine concentrations.

2. Iodine-Rich Regions

While iodine can be found worldwide, certain regions are known for their higher iodine content. These regions often have unique geological or environmental characteristics that contribute to the accumulation of iodine.

2.1 Coastal Areas

Coastal areas, especially those with rocky shorelines, are often associated with higher iodine concentrations. This is because seawater, which contains iodine, interacts with the rocks and soil along the coast, leading to the release and accumulation of iodine in these areas.

Notable iodine-rich coastal regions include the coasts of Japan, Chile, and parts of northern Europe. In these areas, the combination of geological factors, such as volcanic activity and tectonic processes, contributes to the higher iodine content.

2.2 Volcanic Regions

Volcanic regions are known to be rich in iodine due to the release of volcanic gases and fluids that contain iodine compounds. Volcanic activity can lead to the enrichment of iodine in the surrounding rocks, soil, and water.

Examples of iodine-rich volcanic regions include parts of Japan, Indonesia, and the Andes Mountains in South America. These regions often have hot springs or geothermal areas where the concentrations of iodine can be particularly high.

2.3 Iodine-Deficient Regions

On the other hand, some regions are considered iodine-deficient, meaning they have low iodine levels in their natural sources. These regions are often far from the coast or lack geological conditions that promote iodine accumulation.

Iodine-deficient regions can be found in many parts of the world, including landlocked countries, inland areas, and certain mountainous regions. Some examples include parts of Central Asia, Africa, and the Himalayas.

3. Industrial Sources

In addition to natural sources, iodine is also produced and extracted for industrial purposes. These sources play a vital role in meeting the global demand for iodine in various sectors.

3.1 Seaweed and Kelp

Seaweed and kelp are important natural sources of iodine, particularly in regions where iodine deficiency is prevalent. These marine plants accumulate iodine from seawater and can contain high concentrations of this essential element.

Some countries, such as Japan and China, have a long history of using seaweed and kelp as dietary sources of iodine. These plants are also harvested for industrial extraction and production of iodine compounds.

3.2 Saltwater Brines

Saltwater brines, which are underground reservoirs of concentrated saltwater, can contain significant amounts of iodine. These brines are often found in areas with ancient or evaporated seas, such as the Great Salt Lake in the United States.

Iodine is extracted from saltwater brines through a process called brine solution mining. This involves pumping the brine to the surface and evaporating the water, leaving behind the iodine-rich salts.

3.3 Underground Deposits

Iodine can also be found in underground deposits, particularly in the form of iodate minerals. These deposits are typically located in regions with geological conditions that favor the formation of such minerals.

Chile is one of the largest producers of iodine, primarily due to the presence of extensive underground deposits of iodine-rich minerals. These deposits are mined and processed to extract iodine for industrial use.

4. FAQs

FAQ 1: What are the health benefits of iodine?

Iodine plays a crucial role in maintaining thyroid function and regulating metabolism. It is also essential for proper growth and development, particularly during pregnancy and early childhood. Adequate iodine intake can prevent iodine deficiency disorders, such as goiter and intellectual impairment.

FAQ 2: How can iodine deficiency be prevented?

Iodine deficiency can be prevented through various measures, including iodized salt, the consumption of iodine-rich foods (e.g., seafood, dairy products), and the use of iodine supplements. Public health programs, such as salt iodization initiatives, have been successful in reducing iodine deficiency in many countries.

FAQ 3: Can excessive iodine intake be harmful?

While iodine is essential for health, excessive intake can have adverse effects. High levels of iodine can disrupt thyroid function, leading to hyperthyroidism or hypothyroidism. It is important to maintain a balanced iodine intake within the recommended daily limits.

FAQ 4: Are there any environmental concerns related to iodine extraction?

Iodine extraction, particularly from underground deposits and saltwater brines, can have environmental impacts. The extraction process may involve the use of chemicals and energy-intensive methods. It is crucial to implement sustainable practices and minimize the release of harmful byproducts into the environment.

FAQ 5: Can iodine be obtained from non-natural sources?

Yes, iodine can be produced synthetically for various industrial applications. However, natural sources, such as seawater and underground deposits, remain significant contributors to the global iodine supply.

FAQ 6: Are there any alternative sources of iodine?

While seaweed, kelp, and underground deposits are the primary sources of iodine, researchers are exploring alternative sources, such as algae and wastewater treatment plants. These sources have the potential to provide a sustainable and cost-effective supply of iodine.

FAQ 7: Are there any regulations on iodine use?

Iodine use is regulated by national and international authorities to ensure its safe and responsible use. Regulations may cover aspects such as iodine content in food products, maximum allowable levels in drinking water, and occupational exposure limits in industrial settings.


Iodine is a vital element that is found in various sources around the world. From the depths of the ocean to underground deposits, iodine can be obtained naturally or produced industrially to meet global demands. Understanding the distribution and availability of iodine is crucial for ensuring adequate intake, preventing deficiencies, and promoting sustainable practices in its extraction and use.

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