资源环境科技发展态势分析平台

Dioxins have been a focus for the Arctic Contaminants Action Program (ACAP) Working Group of the Arctic Council since 2001. ACAP works together with the Arctic States to learn from each other how to limit emissions of dioxins. ACAP’s projects to reduce or eliminate emissions of dioxins take into account special consideration of communities and the environment in the Arctic.

It is estimated that more than 90 percent of exposure to dioxins occurs via food. High-risk foods include meat and dairy products, fish and shellfish. In the Arctic, many Indigenous peoples depend on traditional foods with a high content of fish. High dioxins levels are often measured in such populations.

Most emissions of dioxins stem from industrial processes. Industries and companies should apply Best Available Techniques (BAT) and Best Environmental Practice (BEP) to avoid dioxin emissions, this is especially important for waste incineration plants.

Here are five key facts to know about dioxins, their impacts on health and how to cut emissions and limit exposure.

1) Dioxins are primarily man-made through industrial processes, but can also be emitted naturally

Dioxins are a by-product of many industrial processes. Large- and small-scale combustion, particularly of waste, is one potential major source of dioxin emissions into the atmosphere.

Another important dioxin source is in the chemical industry, which does not directly contaminate the environment via atmospheric pollution, but rather through the release of the products themselves. Dioxins are also formed in the bleaching of pulp and paper products.

While the majority of dioxins are formed from human activity, they can also form naturally in the environment at high temperatures, such as in forest fires and volcanoes.

Dioxins can be emitted into air, water and subsequently into sediments, land, waste and other products.

2) High exposure to dioxins interferes with hormones and can cause cancer, reproductive and developmental problems and damage to the immune system

While all humans are at risk for health issues related to dioxin exposure, the developing fetus is the most sensitive to negative effects. Newborns, with rapidly developing organ systems, may also be more vulnerable.

In mammals, long-term exposure is linked to impairment of the immune system, nervous system, endocrine system and reproductive functions. Chronic exposure of animals to dioxins has also been shown to result in several types of cancer. TCDD, the most toxic of all dioxins, was evaluated by the World Health Organization’s International Agency for Research on Cancer (IARC) and classified as a “known human carcinogen.”

3) All humans are exposed to dioxins, and they can stay in the body for a long time

Dioxins are found in the environment throughout the world, and they accumulate in the food chain, mainly in the fatty tissue of animals. Their ability to be absorbed by fat tissue also means that dioxins stay in human bodies for a long time. The half-life of dioxins in the body is estimated to be around ten years.

In the environment, dioxins accumulate in food chains. This means that predators show higher concentrations of dioxins than their prey.

4) Some people are exposed to higher levels of dioxins because of their diet or occupation, putting Arctic Indigenous Peoples at higher risk

Some people may be exposed to higher levels of dioxins because of their diet or their occupation – for example, workers in incineration plants and at hazardous waste sites. Because dioxins accumulate in food chains, foods such as meat, dairy, fish and shellfish are considered high-risk. This puts Arctic Indigenous Peoples who depend on traditional foods with a high content of fish at a higher risk of exposure.

Protecting the food supply is critical. This is underlined by the fact that in many parts of the industrialized world, the tolerable daily intake for dioxins as set by food safety authorities is exceeded by significant segments of the population.

5) Industries and companies should apply Best Available Techniques (BAT) and Best Environmental Practice (BEP) to avoid dioxin emissions

Reduction of formation of dioxins can be achieved by modifying and tuning industrial processes. The selection of raw materials can also, in many cases, be of profound importance for avoiding dioxin formation.

Emissions into the environment can be reduced by decreasing the amount of dioxins in exhausts, effluents, products and wastes. Such cleaning measures are specific to different industrial processes.

Reduction of human exposure can be achieved with improved control of food, especially whole foods and foods of animal origin with high fat content. In the EU, there are limits set on dioxin content in a number of food categories. Foods exceeding these limits are not allowed on the market. Educating consumers through dietary advice issued by authorities can also help reduce human exposure.

Industries and companies should apply Best Available Techniques (BAT) and Best Environmental Practice (BEP) to avoid dioxin emissions. BAT refers to the latest state-of-the-art processes, facilities or methods of operation that limit discharges, emissions and waste. BEP refers to the application of the most appropriate combination of environmental control measures and strategies. It is especially important for waste incineration plants to apply BAT to avoid dioxin emissions from waste incineration.

For more facts about dioxins and for related ACAP projects, click here to see all related ACAP publications.